THE EFFECT Cf fflSMHERATOKE AW LMGTH CF STCRACffi OS PAUTABILITY
COLCE AMD nmm CHAMGES IB GAMED
CITRUS AMD TOMTO ffiOHJCTS
EOBMT FMMEB CAEH
A DISSERTATIOH
submitted to
CKEGOSJ STATE COLLEGE
in partial fulfillment of
th© requir©ro©nts for the
degree of
DOCTOR OF FHHOSQHir
A.-FBOVEDJ
Rrofessor of Foo€ Technology
In Charg© of Major
Head of Bepartmsnt of Food TechmLog
Chairraan of School Graduate CoraEiitte©
Dean of Gradaat© Cchool
Date dissertation is prosented September 2^
Typed by Siybil Deauquier
IQ^I
The x^riter x-dshes to expres© his sincere appreciation to Br•
Oliver J« ¥orthingfco% Profeesor of Food Technolog^j and to I^ofessor
I. H. VSiegand, Head of the Department of Food Technology at the
Oregon State College,, for their constructive criticisms and sugges*
tions during the Course of this x-jork.
lodgement is due to
OP.
For a sirailar reason aeknow*
H. T. Blackhurst5 Department of Horticulture
at the Agricultural and Mechanical College of Texas for valuable
help in the preparation of the manuscript.
Acknowledgement is also
given to Krs. F, E, Allison and It's. R* E. Odom for technical
assistance.
Aclmowledgement is also made to ftv. Sam Tayloe^ General Manager
of Rio Farms Inc.*) Edcouch^ Texas for supplying all raw products
and for the use of the canning plant where all products •were packed.
ccmaras
TABLE OF
PAGS
Eav.ag of literatur© .....e».B...<,<»9««0«083
Ascorbic Acid Retention .#00e»99»6,o.»..».3
Hiacin R©tcnti©a . . • • . • »•«■ • ■ • ■ . • , ■» » • . • • « 10
TlrlcBdaie Eetentlom
e
. o « »« « » » «. • . . . * . * « « 11
Riboflaxdn Retention <,*<.#»»«■.
=> . . 12
Paatoth^ntic Aeid Eeteatiea ■»...».»» <.»,«..
Color R©terstIoa * . » .. « « *
e
13
. « « » * * . , « «. • «. 13
Loss In (^ganoSLeptic Attributes • • * » ♦ • • • «•.«.♦,. 18
Kat©rials and Methods « • « •.•«• . « . • o o . 6 • •• .21
. -« . « « . • . . » . . • « « « « • .♦
20
^neflysis of Cabined Grapefruit «?uie© ...... o o « •
30
Analysis of Ggumed Opang© Juic© .. ......... .
U3
DiseuasioM of Results
Analysis of Canned Grapefruit-Change Juice Blend . „ . . 55
Analysis of Canned Grapefruit Sections ••••««••• 63
Analysis of GajMied taaat© juie© •••••.•.•...
7U
Analysis of Canned Tomatoes •»..»•».. .. ••«
8?
SUTTiEiary .*•.•*.... ««•«.« »...»««.... 98
Conelnsions ..<.»......
•
6
«
•
«.......» .102
•9O4«O**4«<»««*0«««»« XUil
LIST OP TABLES
P1QE
Table I.
Table II.
Table III,
Table I?,
Table V*
Table VI.
Table VII.
Table VIII*
Table E.
Retention of Ascorbic Acid in Canned Citrus and
Tomato i^roducts as Influenced by Storage Temp*
QTattare and Tims. A Summary of Brevious Mork.
U
Initial Vitamin Content of Canned Citrus and
Tomato Eroducts*
28
U* S. Grade of Canned Grapefruit Juice as
Influenced by Temperature and Length of Storage
36
Organoleptie Evaluation of Canned Grapefruit Juice
as Influenced by Temperature and Length of Storage
I4.O
U. S» Grade of Canned Orange Juice as Influenced
by Temperature and Length of Storage
$0
Organoleptie ©valuation of Canned Orange Juice
as Influenced by Teiaperature and Length of Storage
52
U» S. Grade of Canned ©•apefruitfOrange Juice Blend
as Influenced by Temperature and Length of Storage
60
Organoleptie Evaluation of Canned Grapefruit-Orange
Juice Blend as Influenced by Temperature and Length
of Storage
61
U. S. Grade of Canned Grapefruit Sections as
Influenced by Temperature and Length of Storage
71
Table X.
Ctrganoleptic Evaluation of Canned Grapefruit Sections
as Influenced by Temperature and Length of Storage
72
Table XI.
U, S, Gyade of Canned Tomato Juice as Influenced
by Temperature and Length of Storage
82
Organoleptie Evaluation of Canned Tomato Juice as
Influenced by Temperature and Length of Storage
Bh
U. S* Grade of Canned Tomatoes as Influenced by
Temperature and Length of Storage
93
Organoleptie Evaluation of Canned Tomatoes as
Influenced by Temperature and Length of Storage
95
Table XII*
Table XIIX*
Table XIV*
LIST OF FIGURES
PAGE
Figure 1.
Retention of Ascorbic Acid.in Grapefruit Juice
2$
Figure 2.
Retention of Siacin in Grapefruit Juice
29
Figure 3»
Retention of IfeiaMne in Grapefruit Juice
32
Figure U»
Retention of Riboflavin in Grapefruit Juice
32
Figure 5.
Retention of Pantothenic Acid in Grapefruit Juice
3k
Figure 6.
Change in Color of Grapefruit Juice
3k
Figure 7.
Kbdachromes of Grapefruit Juice Stored 12 and 2k
months at 3k0s 70° and 110° F.
35
Figure 8.
Retention of Ascorbic Acid in Grange Juice
Id
Figure 9.
Retention of Hiacin in Orange Juice
Ijl
Figure 10.
Retention of Thi&iaine in Grange Juice
Uli
Figure 11.
Retention of Riboflavin in Orange Juice
kh
Figure 12.
Retention of Pantothenie Acid in Grange Juice
k5
Figure 13.
Change in Color of Orange Juice
li5
Figure lk»
Kodachroraes of Orange Juice Stored 12 and 2k
months at 3k09 70°' and 1100 F.
US
Retention of Ascorbic Acid in Grapefruit*Qrange
Juice Blend
53
Retention of Hiacin in GrapefVuit-Orang© Juice
Blend
53
Retention of Thiamine in Grapefruit-*Orange Juice
Blend
5U
Figure 15.
Figure 16.
Figure 17♦
Figure 18. Retention of Riboflavin in Grapefruit-'Graage Juice
Blend
$k
LIST OF FIGURES (GOKTOWUED)
PAGE
Figure \9»
Retention of Pantothenic Acid in Grapefruit**
Orange Juice Blend
$6
Figure 20»
Change in Color of Grapefruit-Orange Juice Blend
$6
Figure 21o
Kodachromes of Grapefruit-Orange Jixice Blend
Stored 18 and 2k months at 3U0, 70° and 110° F.
$%
Figure 22.
Retention of Ascorbic Acid in Grapefruit Sections
&k
Figure 23.
Retention of Mac in in Grapefruit Sections
6U
Figure 2lu
Retention of Thiamine in Grapefruit Sections
&$
Figure 2!?.
Retention of Riboflavin in Grapefruit Sections
6$
Figure 26,
Retention of Pantothenic Acid in Grapefruit Sections
68
Figure 27.
Change in Color of Grapefruit Sections
68
Figure 28.
Kodachromes of Grapefruit Sections Stored 12 and 2U
Months at 3k0s 70° and 110° F»
69
Figure 29.
Retention of Ascorbic Acid in Canned Tomato Juice
75
Figure 30.
Retention of Mac in in Canned Tomato Juice
75
Figure 31•
Retention of Thiamine in Canned Tomato Juice
78
Figure 32.
Retention of Riboflavin in Canned Tomato Juice
78
Figure 33.
Retention of Pantothenic Acid in Canned Tomato Juice
79
Figure 3k*
Change in Color of Canned Tomato Juice
79
Figure 35«
Kodachromes of Tomato Juice Stored 12 and 21*
Months at 31°$ 70° and 1100 F*
80
Figure 36.
Retention of Ascorbic Acid in Canned Tomatoes
86
Figure 37.
Retention of Wiacin in Canned Tomatoes
86
Figure 38*
Retention of Thiamine in Canned Tomatoes
89
LIST OF FIGURES (CGHTIHUBD)
PAGE
Figure 39*
Retention of MbofXavin in Canned Tomatoes
89
Figure UO,
Retention of Pantottenic Acid in Canned Tomatoes
91
Figure lil*
Change in Color of Canned Tomatoes
91
Figure kZ*
Kodaehromes of Tomatoes Stored 12 end 2U Months
at 3h0» 70° and llO0 F,
92
mi EFFECT OF TEMPERATURE AND LENGTH OF STORAGE OH PALATABILlTti,
COLOR MB VITAMIH CHAMGES IN GAMED CITRUS AW TOMATO HtGHJCTS
mmcmcTim
A great vaLume of wrk has been done on methods of food preser~
vation aimed toward a more nutritious product.
All work has been
concerned tdth production of a more acceptable product as to appear*
ance and quality for the consumer.
Studies have covered the period
from the raw material through processing to a finished product.
The
methods of processing ar© good but the problem of holding the product
for future sale has introduced serious difficulties.
E*rocessed pro-
ducts are seldom consumed immediately but must be held £QV shorter or
longer periods due either to demand or to price level.
If storage
conditions are not satisfactory^ changes occur in processed foods
'Which affect the nutritive value, change the color^ influence U. S,
grade and reduce general acceptability of the product*
Even t-dth sharp vigilance over preservation procedures, storage
may result in marked changes in the products«
Thus the processor may
suffer financial loss from change in grade $ or from a lowered demand
by the consuming public.
It is a well established fact that the
average consumer is more influenced by appearance of a product and
its flavor than by the vltamn content. •"
Since practically all canned products are stored for a period
of time at various temperatures, it is important to know- the in*
fluence of time and temperature of storage on quality of the product*
Canned tomato and citrus procbicts represent a considerable
volims of processed foods.
They are produced daring a relatively
short season^ the toiaato season being shorter than that of citmas.9
consequently these products are consumed after indefinite arid
variable periods of storage,
nutritionally it is iiRportsnt to
know the imfluene© of tim© and teaiperatur© of storage oa certain
of the trater soluble Yltainlns in these foods.
From the stan<%»oint
of the purchaser^ it is iu^pcrtant to know the influence of storage
conditions of the palatability le^nsl of the product,
l£s then9
it becomes necessaay to hold canned presets for prolonged periods
the influence of storage conditions should be carefully considered
and the products held under those conditions t-teeh till inSLiicnce
in the least adverse K&a2»er8 nutritive valuej colora U. S» grade
and general acceptability.
REHW OF LITSBATURE
Asc^biq Acid Retention
Ascorbic acid is one of the important water soluble vitamins in
citrus and tomato products.
The retention of ascorbic acid has been
taken as an index to the retention of original nutritive and qualitgr
values,
f^resent processing practices are such as to retain from 92 to
96 percent of the ascorbic acid in canned citrus juices (33).
There-
fores lam ascorbic acid values found in canned citrus juices purchased
on the open market are most likely due to improper storage.
There have been a number of papers published on the influence
of temperature and length of storage on the retention of ascorbic
acid in citrus products.
Grapefruit and orange juices have received
major consideration in these studies tihile grapefruit sections and
grapefruit-orange juice blends have not been intensively studied.
The effect of storage'on tomato products has not been studied under
a t-rf.de range of storage temperatures*
A tabular survey of the literature with reference to the effect
of storage time and temperature on the retention of ascorbic acid in
citrus and tomato products is presented in Table I.
The section
immediately follox-Ang the table contains essentially the same data
and may be used as a source of more detailed information,
Roberts (26) reported that canned grapefruit juice retained
7$ percent of the original ascorbic acid content x&aen stored at
uncontrolled room temperature for 9 to 10 months.
TABLE I,
EETEHTIGH CF ASGCEBIC ACID IH CAM3SD CTSmS Aim TOmW mODUCTS' AS UffiMEHCED BY STQRAGE
TE&ffERATURE MB TIME. A SUHMHff OF mEWIOUS IKKK* ■
I^oduct aad
Stcs^age Tei^erature
Degrees P*
Grapefruii
Jui«e
Mojitlis in Storage
Storagi5
Months
3
6
0°
30°
10°
hDQ
140©
ii50
50©
50©
9
It
1$
15
References
18
m.
SU
100
100
(6)
(6)
(18)
(25)
<6)
(195
(19)
(29)
(6)
(6)
(19}
96
95
9$
99
95
95
95
5GO
6oo
65°
'
9h
96
^
9U
92
.
n
65o
tO®
too
82
(29)
(25)
(12)
88
82
TO©
81
(19)
TO©.
80O
800
88
(6)
(18)
(19)
80O
98oR* T.l
R. T.
65»850
1Room Tei^erattsre
-
82
75
57
31
75
75
73
91
'
(29)
(19}
(26)
(28)
(33)
TABLE It
BETEHHCM OP ASCORBIC ACID Dl GAMED CITRUS AMD TOMATO mODOCTS AS niFLUSHCED BY STCHA®;
^SffmSATDEE AND TIME. A SUI#ffiEY OF mE?ICOS WBK. (CCKTIHUED)
Eroduct and
Storage Teiaperatare
Degrees F.
Orange Juice
h0o
hCP
50°
50°
65°
65°
70°
70°
80©
80°
80°
90©
99°
1100
hk~$2?
a*- T*
R. T*
Grapefruit^ S. T*
Orange Blend
Months im Storage
3
6
9
12
15
Beferences
18
a.
2k
93
9h
75
75
(18)
(25}
(19)
(29)
(19)
(29)
(25)
(3)
(18)
(19)
(29)
(3)
(27)
(3)
(27)
(27)
(28)
72
(28)
9$
9?
90
93
80
88
92
81
78
50
65
31
16
US
vn.
TABLE I.
HETSOTICM OF ASC(BBIC ACID IN CAK1ED CITRUS AID TOMTO ffiOIXfCTS AS II^FLUEMCED BY STCBACS
TEHPMATURE AMD TIHfi. A SUMMEI OF HiEflOUS I^CRK. (CCBTBIUID)
l^oduct and
Stora^ Tender attire
Ite^ees F«
C^apefruit
Sections
Tcmato Jm.ce
3
6
Months; ia Ste^ai:e
12 1$ 18
9
^0°
65°
93
91
80°
73
(19) (29)
(19) (29)
(19) (29)
102
92
(29)
(29)
(7)
(3)
60
Ik
38
no©
no©
So©
6$©
80©
87
77
U6
82
70©
80©
80©
90©
Tojtnatees
21*
92
30°
1<0*?O©
References
a
20
n
90
(7)
(29)
(3)
(7)
(3)
(6)
89
87
70
(29)
(29)
(29)
o\
loore et al* (18) studied the ascorbic acid retention of Florida
grapefruit and orange juice packed in plain cans stored 6 months at
yp to BCPF,
They observed that grapefruit juice retained 96 and
82 percent of the initial content when stored at hO0 and 80° F* Orange
juice retained 93 and 81 percent when stored at the sane temperatures.
Ross (27) reported on the effect of time and temperature of
storage on the vitardn C retention in orange juice*
He stored the
juices 12 months at temperatures of Ui0 to $2° F.s room temperature
and 99° F.
At the end of 6 months the juice stored at 99° F* re*
tained only 31 percent of the initial content.
The greatest loss
in ascorbic acid occurred during the first 6 months^ since at the
end of 12 months there ms still found 16 percent retention.
Juices
stored at the lox* temperature retained 9h percent of the ascorbic
acid after 12 months.
The room temperature storage resulted in a
75 percent retention of vitamin G at the end of 12 months.
Reister et al* (25) stated that storage at IiO® F* retained the
ascorbic acid of unsweetened grapefruit juice and of orange juice
better than at 70^ F* but not as well as was expected*
With orange
juice in plain cans stored at I1O0 F. a retention of 95 percent T«IS
found at the end of 12 months storage.
When the juice was stored at
70° F» only 88 percent of the vitamin G was retained*
For unsweetened
grapefruit juice at ItO0 and 70° p* retention was 95 and 87 percent
respectively.
8
In a short time storage experiment Wagner et al, (33) reported
average retention of 91 percent in grapefruit juice after a period
of hO days at temperatures ranging between 65° and 85° F.
Querrant et al* (?) in a coiaprehensive stu<%- on the effect of
storage temperature vs., tisie found that the ascorbic acid content
of Rutgers tomato SvcLce is seriously affected tr/ storage temperature*
After 36$ days of storage at 3©° F«, 92 percent of the initial as«»
eorbic acid was retained vkxle only 20 percent was recovered from
juice stored the same length of time at 110° F.
He further observed
that at 80° F, the loss of ascorbic acid was only about half as
great as that at 110°
f, for the first 365 days*
Lamb (12) in a stucfy- utilizing California and Arizona grape«»
fruit juice stored at 70° P. for 18 months reported a linear loss of
ascorbic acid at this temperature,
The rate of loss was about one
percent per month thus indicating an 82 percent retention at the end
©f the storage period*
There tsas sosae evidence) that ascorbic acid
of grapefruit juice was more stable in early periods and less stable
in later periods of storage than orange juice*
Sale (28) reported on the retention of ascorbic acid in Texas
packed unS'weetened grapefruit juice^ orang© and grapefruit«orange
blend stored 12 months at room temperature at several geographical
locations*
His results indicate an average retention of 73$ 7$ and
72 percent in these three products.
There was an average of 15
percent loss in the three products after 6 months storage.-
Moschette et al,. (19) reported retention of 95> 95j 92? Big.
1$ and 31 percent in grapefruit juice stored 12 months at temperatures
of k^B 500s 6S09 7O0^ 80° and 98° P,
Grape&uit sections retained
93* 91 and 73 percent of ascorbic acid when stored 12 months at temp*
eratures of 50o? 65° and 80° F* -Hhile orange juice retained 97* 93
and 78 percent under the same conditions*
The products were all fancy
or esctra standard in quality and t-jere examined at intervals of four
months for a period of one year*
Brenner et al« (3) stored orange juice and tomato juice for a
period of 18 months at temperatures of 700s 90° and Ho0 Ft
They
reported 9S| 6£ and hS percent respectively of the original ascorbic
acid content at the end of storage for orange juice*
Tomato juice
retained only 82j 38 and H percent respectively for the same period.
Sheft et al, (29) in a continuation of the work previously reported by Moschette found ascorbic acid retentions above 90 percent
for grapefruit, orange and tomato juices stored at 50° F, for a period
of 2k months*
These workers reported retentions of ascorbic acid of
89$ 87 and 70 percent in tomatoes when stored 2k months at temperatures
of 50°, 65° and 80° F.
Retentions of 102$ 92 and 7i* percent tuere
reported for tomato juice stored for the same time and temperatures
as for tomatoes*
Grange juice retained 95$ 80 and $0 percent! grape*
fruit juice,, 9k9 82^ and 57 and grapefruit sections^ 87, 77 and 1±6
percent of the ascorbic acid tzhen stored at temperatures of 50°? 65°
and 80° P. for 2k months.
10
Feastor et al,. (6) indicated that the temperature at tjhich grape-*
fruit juice was closed had a significant influence on the retention of
ascorbic acid.
Juices cased and stacked at 115° F. required about 17
days to reach room temperatures of 70° F»
four percent of the ascorbic acid tias lost.
In this period approximately
In trials cased at temp-*
eratures of 66° to ?20 F, hi#ier retentions of ascorbic acid were
noted,
Theso workers stored grapefruit juice at temperatures of 00j
30°), h009 50°s 60^5, and 70° F, for one year. Retentions of vitan&n
C of lOOj, 100s 99} 96^ 9k and 88 percent respectively trere reported
at the conclusion of the storage period,
Fcaster et al, (5) reported retentions of vitamin C of 90 per~
cent or better in canned tomato juice,, during a storage period of
9 months at temperatures of ItO0^ 50o5 60° and 70° F,
Juice stored at
kOQ Fp retained only 1,6 mgs, more of the vitamin than juice stored
at 70° F.
Hiacin Retention
Mosehette et al> (19) stated that niacin retention in tomatoes
or tomato juice was never lower than 95 percent Mien these products
were stored at temperatures of 50°^ 65° and 80° F. for a period of
one year.
of storage,
Time was a much more significant factor than temperature
Sheft et al. (29) continued the work of Mosehette for an
additional period of 12 months*
These workers reported retention of
niacin in tomato juice of 923 91 and 90 percent when stored at 50°^
65° and 80° F. for 2k months.
Retention of niacin under the same
conditions was 885; 88 and 85 percent in whole tomatoes.
11
Brenner et al» (3) reported niacin retention of 93> percent in
tomato juice tshen stored 18 months at 70Q5 90° and 110°?..
Thiamine Retention
Guerrant et al| (7) stewed Rutgers tomato juice for a period
of' 3^5 days at temperatures of 30o9 h2Q? 85° and 110° F,
Th^r re*,
ported that thiamine retention t-jas little affected by time but
seriously influenced by the temperature of storage.
At 30° F, there
t-jas essentially 100 percent retention after one year storage*
retention of the vitamin was also favorable at h20 F,
The
At 85° and
110° F.j, the retention was 8£ and 31 percent respectively.
Hoschette et al. (19) reported retentions of thiamine between
90 and 100 percent for grapefruit and orange juice stored 12 months
at temperatures of $00s 6^°, and 80° p..
obtained x-jith lower storage temperatures.
The higher retentions t-jere
Tomatoes and tomato juice
%jere more seriously influenced by the temperature of storage than
were the citrus juices.
After 12 months storage at the two lower
temperatures retentions of 92 to 95 percent were obtained while at
80° F.j 82 and 85 percent retention was obtained fi'om tomatoes and
tomato juice respectively«
It was reported by Brenner et al. (3) that at 70° F.? at least
80 percent or more of the initial thiaxaine content was retained in
orange and tomato juice after a storage period of 18 months*
Thiamine
loss increased with length of storage and xri-th an increase in storage
temperature*
At the end of the storage period retentions in orange and
12
tomato juice stored at lOO^ F, were 3I4 and $$ percent respectively*
Tomato juice showed a better retention of thiajtiine at the elevated
teiaperatures than did the orange juice.
Sheft et al. (29) reported that tomatoes retained 91$ 8? and 70
percent of the initial thiaiaine content wiion stored 2k months at
temperatures of 50o5 $5° and 80° pf
Tomato juice retained 103^, 3h.
and 77 percent8 orange juice^ 101, 5>Ii and 83 percentj t^iile'^rape*
fruit juice retained 99, 9h and 8U percent of thiamine after 2ii mon'tos,
Riboflavin Retention
Guerrant et al9 (7) reported riboflavin retention in tomato juice
at 63 percent after storage for one year at 110° F.
At 30° F. a re*
tenticn of 90 percent t-jas found for the same period*
Moschette et al, (19) report greater retention of riboflavin
in tomatoes than in tomato juice after two months storage at 500s
6$° and 80° F,
Tomatoes retained 91^ 95 and 92 percent, and tomato
juice 89s 85 and 81* percent.
storage temperatures*
The higher retentions tiere tclth lower
Retention of riboflavin increased three percent
in tomato juice and approximately ten percent in tomatoes when stored
for an additional 12 months (29)*
Thus riboflavin retentions of 96
to 98 percent were found in tomatoes and 92 to 3h percent in tomato
juice at the conclusion of the storage period.
Brenner et al* (3) reported an increase to 125 percent of the
initial riboflavin content in tomato juice stored at temperatures of
70°, 90° and 100° F. for 18 months.
13
Pmtother&c Acid Retention
The influence of storage conditions on the retention of pantothenic
acid in tomato juice %ms studied by Guerrant et al. (7).
They
foimd that tenperature of storage eacerted a definite effect upon the
retention of the -yitamin but that time of storage did not appear to
influence seriously the retention of pantothenie acid,!
Storage for
36$ days at temperatures of 300s h20s &h0 and 110° F. resulted in
retentions of 85^, 77$ 6h and k5 percent respectively.
Color Retention
Hie retention of color in citrus products has been the subject
of a great deal of research.
Although the degradation of color in
food products is still not fully explained certain factors that may
play a part in loss of color are Icnoxim.
Qsygen appears to be partially
responsible for color deterioration as evidenced by the work of Nolte
et al, (22)5 Blester et al. (25) and Boyd and Peterson (2),
Mien the
experimental conditions were such that more 02§rgen was allowed to
become associated with the juice the color darkened*
Decreasing the
headspace5 partial deaeration,, repeated evacuation and release with
inert gases all tending to reduce the oxygen content resulted in less
color deterioration*
That darkening of the colot of citrus products
was associated with decrease in the ascorbic acid content was noted
by Hairiburfer and Joslyn (8).
These workers stated that darkening of
filtered orange juice did not QCCXVC until the vitainin C was in the
dehydro or some other form and there were no other readily oxidisable
substances present in the juice.
Moore et al., (17) investigated 'the relationships of darkening
td.th headspace, oaygen content^, added ascorbic acid and color bodies
of Valencia orange juice.
She juice was filtered to facilitate color
evaluation by transmitted light*
The filtered juice could not be
considered equivalent to canned juice.
and 120® F* for one x-jeek*
The juice was stored at liG0
In one phase of the experiment whole and
filtered juice were brought to certain volumes by the addition of
color bodies *> pulp^ split seeds5 ground peel, ascorbic acids citric
acidp sucrose$ dextrose and levulose*
These idjctures were then
processed^ scaled in bottles and subsequently stored at bO0 and 120° F«
fheir results indicated that filtered juice darkened at the same rate
as whole juice and that none of the additives3 except ascorbic acid
accelerated the rate of color degradation.
Juices packed with a
headspace of 10 mis. as compared to £0 mis. did not darken as
rapidly.
The addition of ascorbic acid in the presence of a large
headspace (0^ content) definitely increased the rate and degree of
darkening in the filtered juice.
They summarized their work by
stating that oxygen and ascorbic acid xrare the two most important
factors associated with darkening and that the rate of darkening was
accelerated by high temperature*
Color estimation in food products is not a particularly simple
matter*
In the past the estimation of color has been entirely sub*
jeetive and open to the criticisms attendant thereto.
There is a
need for some entirely objective description of color of foods that
is not open to as many critisms as the subjective methods.
On© of
15
the earliest reports relative to a serai^objective method used mth
orange juice was the work of Joslyn et al. (10)*
These investigators
measured the extent of brotming and change in reducing valu.e of arange
juice exposed to air.
Their results t-rith the Lovibond tintometer
indicated that during the process of darkening there ms a gradual.
increase in the red units x&ile the yellow units remained fairly
constant*
Practically the same results have been obtained by
Pederson (23) using the Lovibond tintometer to measure the rate of
darkening in apple juice*
at the higher temperatures*
He also found an increase in red units
The increase in red units while yellow
units remained constant was associated with a decrease in the re«>
ducing value as evidenced by iodine titration*
Ivhile this method
consists of visual color comparisonss the results are expressed
numerically and not with adjectives*
In a later report Moore et al* (18) stored orange and grape«»
fruit juice in plain cans at 1*0° and 80° F. for six months*
The
expression of color change was through the Maerz and Paul "DLctionary
of Color"*
"While the color comparisons are made visuallys, the re~
suits are expressed in letters and numerals*
These workers reported
that there was no change in color of the juices stored at the lower
temperature but that at the end of the storage period at 88° F* the
juices had darkened*
Riester et al* (25) also reported that storage
of citrus juices at Uo0 F* resulted in better color retention than
storage at 70° F*
The results of Moore et al* (16) indicated that
16
the Change in orange juice held at ?66 F. uas from Elate 10*-L*»3 to
10*1*5 x*iile in grapefruit juice the change was from Plate 10«C*1 to
10*D»1»
Kiere was no change in juice held at liO0 F.
IfJhen these data
are transcribed to Munsell notations fey reference to Nickerson (21)
the following relationships esdst?
Grange Juices
Plate 10~L-3 is equivalent to $1 8,0/9.0
Plate 10->l*ii is equivalent to U,5Y 7.7/9*0
Grapefruit Juices
Hate 10-C«.l is equivalent to 10Y 8^/2*2
Plate 10-I>-1 is equivalent to 10Y 8il</2*8
These data indicate an increase in red hue5 a decrease in value
(t&iteness) and the maintenance of constant chroma for orange juice*
The data for grapefruit juice indicate an increase in chroma units
only.
Ross (2?) reported that canned orange juice stored at 90° F#
for four months was "off-^color" due to brcmning and that after six
months at this temperature the juice was dark brown in color.
On
the other hand when the juice was stored at temperatures between.
U50 and 80° p. no apparent color differences were expressed*
L'orthington et al. (.3^) reported on the use of the Fhotovolt
Reflectometer with tristimulus ambers ^een and blue filters as an
objective method of color specification,
Bty the use of appropriate
formulae the values obtained by the reflectometer may be converted
17
to a Hunsell notation*
This method ^-jas used to determine the Munsell
notation of a number of different unclarified juices,. herein absorp-.
tion speotrdphotoBietry could not be applied and lahereitt the visual
color is due not oaly to pigments but to the quantity and state of
division of fine particles*
A search of the literature failed to reveal asny reports on the
influence of storage conditions upon the U. S* grade of canned .
foods*
as
Previously mentioned work on color made mention of such terms
53
off-grade" but the terminology did not iroply the application of
grade requirerasnts to the products*
The importance of temperature in maintenance of quality in
canned tomto juice t-ms studied by Feaster et al* (5)*
Canned
tomato juice I'jas subjected to temperatures of l!.0os 70° and 98° F*
iSvery four months the samples were shifted to a different temperature.
The samples were stored for four months at each temperature but the
sequence of temperatures ms altered.
Their results show conclusively
that a storage temperature of 98° F* very seriously influenced the
quality as measured by the ascorbic acid retention,
The sequence of
placement in the various storage temperatures did not appear to
eaoert any influence*
Monroe et al* (15) reported average warehouse temperatures in
four cities tjhere canned food storage facilities are available*
Their studies showed that in i-jarehouses located in Yuba? Californiaj
Hew Grleansa Louisiana! Rochelle5 Illinois and Tampa^ Florida there
18
isere llt? 2hOs S3 and 200 days respectively yhen the x%arehouse temp*
erature exceeded 80° F,
At Ytiba and Rochelle only Ik and ^0 days
respectively xrere recorded vtith can temperatures in excess of 80° F,
In Metj Orleans and Yubaj, there was an average of five months during
■which time the temperature exceeded 80° F.
joss in Organoleptlc Attributes
Flavor t-as fo\ind to be well preserved in orange juice at refrigerated storage temperatures of hbP to Si0 F* by Ross (27).
flavor v&s judged by two people.
The
Ross stated that juice stored 12
months in the refrigerator had an excellent flavor.
Juice stored
at room temperature possessed a good flavor ■> although it ms slightly
oxidized.
able.
The juice stored at room temperature was not objection-
Mien stored at 98° F.^ the flavor became caramelised and
oxidized at three months and at sis months it was distinctly disagreeable.
He further stated that loss in ascorbic acid and flavor
seemed to follow each other at any one temperature,
Reister et al. (2$) point out that mth canned grapefruit and
orange juice storage at 1*0° F. seemed to maintain the color and
flavor better than storage at 70° F. although the effect was not
great.
There was no mention of the number of judges used in the
flavor panel.
Brenner et al. (3) found that palatability of orange juice
stored at 100° F. deteriorated below acceptability after sis to
eight months storage.
The taste tests were made at the Quartermaster
19
Food and Container Institute for the Armed Forces utilizing a panel
of judges.
Grapefruit juice stored two years TMS unpalatable as reported
by Sheft et al» (29).
The storage temperatures used in this stucfy-
were £0°* 65° and 80° F.
Mo mention of palatability was made of the
other productSj) orange juice^, grapefruit sections^ tomatoes and
tomato juices used in the work and stored for the same interval.
Feaster et al* (6) utilised h to 6 judges to evaluate the flavor
of canned orange juice steered at temperatures of 0oj 30°$ UO0., 50°
and 70° F* for one year.
They stated that after 3 months at 60© to
70° F. a slight flavor change was indicated and was detected by
only a few of the judges.
After 7 months at this temperature a
majority of the judges were able to detect the change in flavor.
At 50° F. or lower no changes x^ere reported throughout the one year
storage period.
An appraisal of the preceding literature reveals a need for
further work on the influence of temperature and duration of storage
on certain of the water soluble vitamins in citrus and tomato products.
Objective methods of color measurement have been developed which may
show more precisely the degradation of color of these products when
stored under adverse conditions.
Apparently there are no data which
show the relationship of the storage conditions to the U. S. grade*
It is the purpose of this paper to show more explicitly the relationships between vitamin content^, color<> U. S. grade and organoleptic
20
evaluation of citrus aad toaato products as influenced by the
storage conditionsi
a
MTERIALS AHD ICTHODS
The citrus and tomato products used in this investigation t-jere
grom and processed in the Rio Grande Yalley of Texas,
All products
xjere hanrested and processed tnth the least possible delay.
The grapefruit juice xms from the Marsh Seedless variety and
t-jas processed as follows.
The fruit x-jas soaked in hot Xirater from
7 to 9 minutes a scrubbed and spray rinsed and elevated to the Faulds
Rotary presses for extraction.
The juice was passed through an
0.020 inch finisher and then to a pasteurizer where it t<ras subjected
to a temperature of 190° F* for 15 seconds*
It was filled in U6 os«
plain cans by use of a bottom filler which materially cut dom on
the amount of foaming.
The cans were closeds inverted and allowed
to air cool for 10 seconds and then rolled under cold water sprays
to reduce internal temperature to 100° F. or lower.
The juice x-ias
not subjected to mechanical deaeration nor x-jas deoiling equipment
used in the process other than the hot xiater soak t^iich aided in
oil removal from the rind.
The grapefruitworange juice blend was processed in the same
manner described for grapefruit juice*
Marsh seedless grapefruit
and Valencia orange juice were blended in stainless steel containers
at a £05 5>Q ratio.
Valencia orange juice xms processed in the manner as outlined
for grapefruit juice but \JSLS placed in plain 307 x U09 cans.
22
Duncan grapefruit \ms used fear sections*
The fruit was washed
in tjater at 1&)0 F. to remove oil from the rind and clean the fruit*
It was then placed in -mber at 190° F» for $ to 7 minutes*
After
peeling, which removed the flavedo and most of the albedo5 the fruit
was passed through a 2 percent lye solution for 3 to 5 minutes for
further removal of albedo.
It was then washed through three changes
of fresh waters spray rinsed and conveyed to the sectioniaers*
Sec-
tioning was done by hand and the sections hand packed in plain 307
x h09 cans,
A 3!?0 BSC±K sugar solution was used as a cover syrup.
The cans were steam-flow closed and processed for 20 minutes at
18^° F.j cooled in water and cased.
Tomatoes and tomato juice were packed in June 191+9 from the
Rutgers variety.
The fruit was harvested in the morning and packed
in the afternoon of the same day with less than a six hour delay.
As in the case of the citrus products^ the normal operation of the
production line was stopped to create a distinct break in the flow
of the product^ after which the fruit used in this stucjy was placed
on the line and packed.
The experimental material was thus sand-
wiched in the normal production operations and the plant personnel
handled the product without regard for the fact that it was experi~
mental work*
Tomatoes were harvested at a full red stage of inaturity9 passed
over a roller inspection table to remove culls and immersed in water
at 200° F. for 2 minutes for scalding.
They were then sprayed with
$3
jets of cold water and hand peeled.
The peeled ioiaatoes wre mechanic
cally filled into plain 30? x k09 cansa steam flow elocedf, processed
38 minutes at 212° F, and tj&ter cooled*
For juiceg the tomatoes were culled5 cored^ hot broken and ex~
tracted through a 0*020 inch screen*
The juice was heated to 210° F*
for S seconds and filled into kS 02s* plain cans.
The closed cans
were further heat treated for 25 minutes at 212° F.
Fourteen cases each of the citrus and tomato products were
brought to College Station,, Texas,, and placed in constant tempera*ture iraults.
The citrus products were packed and placed in storage
in January 191$ while the tomato products were packed in June 191*9 *
From 5 to 6 cans of each product tfere graded after canning by per*
sonnel of the U.S*D.A,S P,M„A.5 Processed Food Inspection Service
stationed in the packing plant.
' The storage temperatures used throughout these experiments were
3h0$ 70° and 110° all £30 p.
^il heating and refrigeration e|uipinent
tiras thermostatically controlled.
The vaults were brought to the
specified temperature several days before the products were stored.
The size of sample for periodic analyses was 6 composited 1^6
oz* cans and 8 composited 307 x k09 cans.
Duplicate chemical analyses
were made at 3 month intervals from the date of initial analysis.
The
ii4terval between packing of the product and the initial analysis nev®r
exceeded 2k hours.
All products were analysed for the following factorst
U., S.
grades objective colors subjective color, flavor and acceptability!
2h
£&& for the.following vitaminst
ascorbic acid^ riboflavin, panto*
thenic acid5 thiamine and niacia*.
The U,.S, grade of the products ims determined according to U. S«
Standards for grade of the product in question (32),
The attributes
of grade are different for the various products and may be determined
by reference to the tables lahich show change in grade as influaneed
by time and temperature of storage*
The objective color »s determined with the aid of a Photovolt
reflectoraetery according to the technique of Dorthington et al. for
juices (3U).
The determnation of color of citrus sections and tom-
atoes required adaptations of the previously mentioned method*
The
search unit is not constructed for vietring a curved object and it
was therefore necessary to comminute the grapefruit sections and
tomatoes by th6 use of a blendor*
The ratio of the solids/liquid
protions of the cans was maintained in samples used for color determi*
nations.
The blendor whipped air into the product causing a drift in
percent reflectance as the bubbles dissipateds necessitating deae*
ration at 21^' for 1$ minutes in a vacuum desiccator*
A large de*
siccator mad© possible the agitation of the sample during deaeration
and reduced the time necessary for the operation«
The deaerated samples were transferred to special bakelite
sample containers made of 3s' black tubing cut into sections and with
a plastic plate glued over one end.
The containers were l-^' high and
were filled to the top with the sample,
A special search unit collar
was placed on the top of the sample cup to exclude stray light and
to allow for perpendicular placement of the search unit on the sample
cup.
The collar was so jr&lled that the bottom interferred with
reflectance of the ptilped
citrus sections*
1% was neeessafy to use
a 307 x 1)09 tin can as the sample container for sections.
was also very satisfactory for 5'uic-©s*
The can
&rber5 blue and green tri*.
stimulus filter's were used x-iith the search unit and data obtained
iVoin percent reflectance of these filters converted into Munsell
notations<
This is a rather laborious mathematical process and the
resultant notation which involves hue4 value/chroma is difficult to
interpret by persons unfamiliar with Kunsell notations*
In addition
Munsell notations are difficult to present graphically*
A stucfy of
tho data revealed that the amber/green filter ratio increased with
time and temperature at 110° Fj,
The readings or ratios of percent
reflectance did not change at 3k0 or 70° Fi
The readings or ratios
of percent reflectance did not change at 34° or 70° F*
These data
•Nhich indicate change in color are therefore the ratio of average
amber/green filter readings*
Subjective color5 flavor and acceptability were obtained accord**
ing to procedures of the Food Technology department^ Oregon State
College (lU)i
Samples of juices,, grapefruit sections and canned
tomatoec were allowed to corns to room temperature before they were
graded by the judgesi
Juices were placed in 100 niU beakers while
the grapefruit sections and tomatoes were served in I4. inch White
26
dishes.
Three samples,, one of ti-iich -was duplicated,, tjere presented
to each judge*
Wnen the 110° P. ssuraples x-jere no longer acceptable^
they were excluded and the judgements isrere limited to teo samples
together with a duplicate,
Thore were never lees than eipjit judges rating the saiaples.
Th© majority graded the samples from the inception to the conclusion
of the experimnt*
They tjere asked to rate the samples on the basis
of color^, flavor and acceptability.
Th© range of score which could
be givfiqSffjas 0 (repulsive) to 10 (ideal).
The data presented are
the averages of the numerical scores of all judges*
Reduced ascorbie acid content
of the products laas determined
according to the Method of Loeffler and Pointing (13).
Sample©
for this analysis consisted of 25 graras of the well ameed juices or
25 grams of a slurry of the citrus sections or tomatoos*
The slurry
was composed of one^tenth the t-reight of the free liquor and of the
solid material.
A Lurastron photoelectric colorimeter was used
throughout the course of the experisoent.
Riboflavin content was detersidned by the isethod of Snell and
Strong (30) using Lactobacillus casei as the test organisms.
The
pure culture of L. casei was obtained f^ora the Jroerican Ity-pe Culture
Collections and x-ma re<=stabbed from stock culture every week.
Pantothenic acid determnations t-jere according to the method of
Neal and Strong (20) using Lactobacillus- casei as the test organism.
Miacin was determined by the method of ICrehl^ Strong and Elvehjem
(11) usinp Lactobacillus arabinosus 17-5 as the test orcanisn.
2?
IMaiKine was detormined "by the thiachromc method as outlined by
the Association of Vitamin Chemists (1),
Kodachrome slides xiere mde at intervals of six months on aH
of the saxaples9
Products, stored at 110° F» x-3ere eliminated from the
slides triien they had become unacceptable,
Tne back^ound used through-
out the course of the experiments xms a light blue cardboard*
The
X-Jeston rating of the light directed onto the samples tjas 1006
1
constant lens opening and exposure time were maintained throughout.
The differences esdiibited in the figure are due to change in develops
ing processes and could not be controlled*
These slides do show the
apparent change between the samples at any one tiine interval but'should not be coMpared as time vs» time because of the change in
developing process,
tiien the products stored at 110° F. began to swollan ©damnation of the sdcrobiological flora was made by using standard
nutrient agar acidified to pH 3*3 with sterile citric acid and trath
toiaato^d^ctrose agar.
The plates were incubated at 110° F, for
? days*
Analysis of the gaseous contents of the headspace of the
swelled cans was made according to the procedures reported by
Clark (U).e
A Fisher•-Gnsat gas analysis apparatus was used for
collection and analysis.
28
DISCUSSIOK OF RESULTS
The results tsrill be ppeBettted in the folXot&ng order? grape*.'
feuit juicej orange Juice? grapefruit-worange •Jwic© ble»da grapefSruit
sections, tomato ^vdjae and tomatoes.
The individual analyses for each
product trill be disctiseed as followss
ascorbic acid, r&aci% thia«
sainej riboflavini pantotheaic acid, change in color, tl* S* grade and
orgaaoleptie evalttation*
The initial analyses for color, U, S. grade and orgaaoleptie
©■wairations are presented in ttie appropriate figures and tables*
Th© initial analysee for the Tltarain values of the citrus and
tomato products are presented in Table II*
These values are in
agreement tJiUh those reported by Thompson et aL.* (31)* P^essley et al.
(2k) and lines ©t al, (9),
fstole II*
Initial fitaMn Content of Canned Citrus and Tomato f^oducts
Ascorbic
Acid
Hiaein "EttLaftim Riboflavia Pantothenic
Acid
feo^act
(r/gpi*)
(r/m*)
(r/m*)
t,h3
0,388
0.500
0.102
0.13U
1.1(3
1.69
14*13
1^2
0,387
0,102
l.li3
31,81t
16, ?5
17,140
2,00
6,98
6,36
0,275
0.905
0,833
0*10li
0,396
0.277
1.72
U.53
2.65
(xRgs,A00 gms.) (r/gm,)
Grapefruit
Juice
Grange Juice
Orapefruii*
Qprnge Juice
Blend
OrapeiVuit
sections
Tomato Juice
Tomatoes
31,68
mas
2,67
100
90
-
SO
-
70
60
TORAGE TEMPF.kATURES
50
<
h
Z
40
uit^vd.'-u
no" f
so
20
\
10
9
12
15
MONTHS IN STORAGE
F"IG. I
99
18
RETENTION OF ASCORBIC ACID IN GRAPEFRUIT JUICE
-
93
STORAGE TEMPERATURES
Aim
A 34°F.
37
z
o
94.
z
h
Ul
K
111
O
95
94
89
9
\Z
IS
MONTHS |N STORAGE
FIG. £
RETENTION OF NIACIN IN GRAPEFRUIT JUICE
24-
30
Analysis of Gamed Grapefruit i»?ui<Se
Ascorbic acid.
The reduced ascorbic acid content of the grape*.
fruit juice after canning uas 31»68 tngs* per 100 gm*.
As T&II be
seen from Figure 1, retention was not Seriously influenced by time
in the 3ii0 and ?00 p, storage bttt taas very greatly affected by 110° p.
storage*
Figure 1 shows recoveries of 99 a&d 97 percent ascorbie
acid after 12 and 2h months storage at 3V F» and a reduction to 7
percent after only 12 months at 110° F.
At the end of 12 months the juice stored at 110° F* %BS no
longer palatable and the analyses for ascorbic acid were discontinued.
The very rapid loss of ascorbic acid at 110° F. coincided xdth decrease in U. S* grade, organoleptic values and color«
These relation*
ships will be discussed in later sections.
Miacin.
The loss of niacin by the grapefruit juice ■was negligible,
Neither storage temperatures nor time of storage was sufficiently great
to affect the nutritive value (Figure 2).
After 2h months at temper-
atures of 3k0 and 70° P. the retention was 89 percent as compared to
93 percent after 18 months at 110° F*
It should be noted that the
graph for niacin is somet-tiat deceptive dtae to the scale used and the
actual loss is not great.
"While grapefruit juice is not a good
source of this vitamin it is interesting to note that a retention of
approximately 95 percent could be expected after 12 months storage at
any temperature between 3k0 and 110° p.
Si
Thiaraine*
The curve for retention of thiamine in grapefruit
juice was similar to that for ascorbic acid.
Data in Figure 3 indicate
that at 3h0 and 70° F* the length of storage plagrs a minor role in
the retention of thiamine.
the first three months*
At 110° F* the loss is very rapid during
After 12 months storage at 31?$ 70° and 110° F«
recoveries of 10©e 92 and %h percent were made*
It should be noted
that J4.0 percent of the thiamine was lost in the first 3 months at
110® F. with only 29 percent additional loss at 15 months storage.
Thus it appears that at higher temperatures the first three months
are most critical.
The trend in thiamine during the first 3 months
at 110° F. is similar to that of ascorbic acid.
It appears that with
respect to these two vitamins grapefruit juice should not be stored
under conditions rahich would allow for high temperatures for any appre-*
ciable length of time*
Riboflavin.
The retention of riboflavin gave results (Figure k)
similar to that of thiamine.
A loss of 5 and 8 percent was indicated
after 12 and 2'lj. months respectively at 3^° F.
and 20 percent at 70° F.
This is compared to 12
At 110° F. the jmce lost 1*2 percent of the
riboflavin during the first 3 months and 9 percent additional with
continued storage for 18 months.
is peculiar.
The recovery tsas 58j lU and 16 percent for the 3$ 6 and
9 months periods at 110° F.
percent.
The curve for riboflavin retention
After 12 months there x-jas a rise to 53
The explanation here appears to be that either there x-jas a
condition created from 9 to 12 months within the juice actually
32
100
90
80
z
o
tz
Id
I-
h
z
u
70
STORAGE .TEMPERATURES
60
0«— O Trf F
50
oli IO* F
40
30
20
10
O
9
MONTHS
12
>5
IN STORAGE
FIG.3 RETENTION OF THIAMINE
21
24-
IN GRAPEFRUIT JUICE
too
STORAGE TEMPERATURES
0«"i""0 TO'F
a^MBva no* F
9
12
IS
MONTHS IN STORAGE
FIG 4- RETENTION OF RIBOFLAVIN IN GRAPEFRUIT JUICE
_l_
24-
33
liberating more of the vitasnin cr that certain cheraical eonstituents
se4#up within the container and not excluded from the sanjple provided
additional grotjth factors for the organism employed*
The difference
is too great to be attributed to experimental error*,
Pantothenie acid.
The retention of pantothenic acid (Figure 5)
•was influenced by both temperature and length of storage,
Pantothenic
acid appeared to be more delicate than the other vitamins even at the
Xot-jest storage temperature.
Storage at 3h9 F, gave recoveries of
$0 and 71 percent after 12 and 2h months respectively.
comparison to 79 and 53 percent at 70° F,
This is in
After 3 months storage at
HO^ F, the loss ©f pantothenic acid was 16 percent xAile the juice
appeared to lose about 10 percent during each of the succeeding four
analyses.
Juice stored 18 months at 110° F. contained only 39 percent
of the original pantothenic acid.
Change in color.
An inspection of the data indicated that the
most reliable index of color was the ratio of the amber/green tri~
Stiraulus filter readings.
The Photovolt reflectometer measures
reflectance of amber^ green and blue tristimulus filters from the
sample as contrasted -with the reflectance of these filters from mag*
nesium oadde,
The data obtained from canned grapefruit juice stored
at 3h® F» as compared with that stored at 70° F* did not show any
consistent variation in the filter readings from the initial examl*
nation.
Titiil© the individual filter readings did change in respect
to length of storage there was no consistency in the direction of
3h
100
^•5
90
■\
z
o
80
•
70
•
<b0
-
50
-
40
-
30
•
20
-
10
-
h
z
u
STORAGE
TEMPERATURES
Q n
i Q
0«B^am
3
TO' F
II0°F
l
i.,
1,
IZ
15
MONTHS IN STORAGE
18
21
,
.-
.24-
FIG. 5 RETENTION OF PANTOTHENIC ACID IN GRAPEFRUIT JUICE
a:
ui
u.
e
h
in
GC
STORAGE TEMPERATURES
A MM A 3VF
OMMWD 70° F
E.<v
2.2
-
Z.O
-
OMMBO 110° F
(-
z
Id
LI
Id
a
<
o
1
9
12
MONTHS IN
FIG.fi
IS
STORAGE
CHANGE IN COLOR OF GRAPEFRUIT JUICE
24-
35
340F
ll0oF
GRAPEFRUIT
JUICE
STORED 12 MONTHS
34 WF
GRAPEFRUI
70 F
JUICE
STORED 24 MONTHS
Figure 7.
Kodachromes of grapefruit juice stored 12 and 2h months
at 3li0, 70° and 110° Ft
M
M
E*J
BS
<3
e
©
N
El
O
to
t3
m 0
§3
o
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36
change.
37
With juice stored 110° F. there x'aas a decrease in the mag-
nitude of the reflectance from each of the filters as the storage
period was increased.
The green filter gave decreases of greater
magnitude than that of the amber filter.
It appeared that the ratio
between the amber/green tristimules filters would show "browning"
better than a single filter index.
As will be noted in later sections
the amber/green ratio gave the most reliable measure for color in
other products as well as with grapefruit juice.
The ratio of the
amber/green filter readings on grapefruit juice was 1.00 at the beginning of the experiment.
This ratio (Figure 6) did not change
materially during 2h months storage at 3k0 and 70° F.
The Koda-
chromes of canned grapefruit juice stored for 12 months at 3it0s 70°
and 110° F. was decidedly brown after 3 months storage and became
increasingly darker with continued storage.
There was a gradual
increase in the amber/green ratio up to 6 months when it began to
increase markedly.
At 110° F. storage the correlation coefficient between browting
(Figure 6) and ascorbic acid content was -0.8^2t0.086s
ns 10.
The
amber/green ratio did not change abruptly until 55 percent of the
ascorbic acid had been lost.
The slope of the curve for color
change was more rapid between 6 and 12 months than the ascorbic acid
curve for this period.
U. 3. Grade.
The U. S. grade of canned grapefruit juice is pre-
sented in its component parts in Table III. As shown in the table the
juice was grade A at the beginning of the storage. The juice held at
38
3k0 F. did not^chang© materially in any attribute of grade.
The
points for color varied by 1 and for absence of defects and flavor
by 2 points each.
There was little change and certainly not one of
economical importance during the git month period at 3h0 F.
Mien the
juice me stored at 70° F*s there t-ras a variation of 1 point in color
during the first 8 examinations.
This agrees with the slight change
in aniber/green readings as show* in Figure 6*
'Hie absence of defects
faotor t-ms practically the same as for the 3hP F* storage.
The flavor
score for the 70° juice decreased gradually during the entire period.
At 9 months it was 3h mtfc a total score of 89«
flavor score ms 33 with a total score of 89.
At 12 months the
It should be "noted
that although the total score is the sasa&a the regulations x-jhlch
apply to the scoring system for grapefruit juice (32) limit juice
with a flavor factor of 28<=33 inclusive to U. S. grade G regardless
of total score.
Consequently the grapefruit juice stored 12 months
at 70° F« ms considered to be U. S. grade C.
This is important
since the change in gfade for flavor occurred between the 9 and 12
month interval.
This means that if canned grapefruit juice is stored
at 70° F. for 9 to 12 months or longer the grade will be lowered.
After 9 months storage at 70^ F»., if the juice were to be held for
a longer periodj it would be necessary to subject the product to a
low temperature in order to prevent further deterioration of flavor.
The situation vrlth regard to juice stored at 110° F. "is quite
different.
Color loss was rapid and the juice was D. S» grade D
39
after 3 months.
Increasing the storage period at 110° F* resulted in
steadily decreasing points for color*
did not change materially^
The absence of defects score
The flavor score at 3 naonths was 28 which
would have been a U, S.« grade C product had the color net limited it
to U# S* grade D9
Thus within 3 months storage at 110° F. the U» S,
grade will drop to D or substandard and the -product is no longer
rearbs table.
It appeared that under the conditions of this experimant a change
in a positive direction of 0,14 from the initial color ratio (amber/
green) will result in a reduction of U, S, grade from the standpoint
of color and flavor at 210o F, is in agreement with loss in ascorbic
acid and increase in amber/greGn ratios.
The remarks above in connection with flavor as the limiting
factor in juice stored at 70° F, for 12 months or longer and both
color and flavor in juice stored at 110° F, taay be seen in Table I?
which summarizes the organoleptic evaluation,
Organoleptic evaluation.
The organoleptic attributes which the
judges were asked to score were color9 flavor and acceptability.
The
data in Table IV show very little change in these three factors for
grapefruit juice stored at 34-° F. f;r 24 months„
With regard to
flavor^ the panel rated the juice 6,5 (fairly good to good) at 9
months and assigned decreasing values for subsequent examinations*,
thus accounting for the change in U* S. grade.
Grapefruit juice stored at 110° F. changed rapidly in color
as evidenced by U. S, grade (color., Table III) and panel score
tmm If*
ORSAEKgEFTXC MALUAfIOH OF CfflMD GEAPIFEDIT JUIGE i>S IHFKQEBGBD
BY TSHiSRJTUBB AID ZSBGTR OF SfOE$m
f©mperattare of Storage
Hontfes
In
HD© F.
70° P.
34°
Storage
Color
Fla-r<
Fla-rof
Aeceptability
Color
Fla^os3
Acceptability
Color
Flavor
0
3
6
9
12
8^0
8.1
8,3
8^2
8.1
7*8
8,4
7.9
8.5
8.0
8.2
8.2
8*0
8.0
8.2
8*0
8*0
8.0
6,6
6.6
6.2
4o5
4o5
4o8
7.8
2*4
1*2
B,5
7*8
7.6
7.1
6,5
6*8
6*5
4*5
4.5
4.6
8.0
3.0
0.9
15
18
8o0
7.7
8.5
7*8
8.4
8.2
8.2
7.7
7»2
21
24
8*8
8.1
8*2
7..8
8.1
8.2
8*0
8,0
S.J0
00-2
leeeptabillty
8.0
0.9
s
Ijl
z
o
z
LI
\cc
^-
z
u
u
9
12.
\S
MONTHS IN STORAGE
FIG.S RETENTION OF ASCORBIC ACID IN ORANGE JUICE
100
98
9£>
z
o
94
t2
lu
H
92
Or
90
U'
^-
z
u
u
or
as
St.
0.
STORAGE TEMPERATURES
C mmmC
TO" F
8*
S2
80
9
IZ
IS
MONTHS IN STORAGE
21
FIG. 9 RETENTION OF NIACIN IN ORANGE JUICE
24-
Table I?*
The judges refused to sample the juice after 6 months
storage*
"Epical remarks with regard to the juice Tijeres
good juice, very good" after Zh months at Sii0 F*
70° p, received such remarks ass
'"estcelleni^
Juice stored at
"slight cam flavor^, metallic
(3 months) slight off "-flavor (6 months )$ terpene flavor (9 months )s
terpene and metallic (12 months )$ slight acidity,, tin flavor^ metallic
flavor (18 months}^ decided off-flavor, color slightly off, slightly
flat (21 months) and strong decided off~flavor (21* months)1"*
three months at 110° f, remarks were*
After
"slight can flavor, after
flavcr, sli#t off color and off flavor1", and after sis months
"very poor, terrible, not acceptable under any circumstances".
General remarks and observations.
During the course of the
eisperiment the cans stored at 110° p, began to swell*
for all products studied.
Sixth to ninth month*
This was true
Hie -swelling of containers began from the
It appeared that a thermophile might be re**
sponsible for the spoilage and swelling of the cans which subsequently
split open along the boc^r seam*
Accordingly a bacteriological exami*»
nation x-jas made of all the products as swelling began to occur.
organism could be demonstrated and it was concluded that spoilage
was due to chemical reactions*
Examination of the headspace gases disclosed between 65 and
70 percent hydrogen with the remainder being carbon dioxide and
nitrogen.
There was no osygen present which suggested hydrogen
No
h3
swell*
The interior of the plain cans showed excessive corrosion
and there ms no doubt that pinholing had occurred and that the
swell t-jas due to formation of hydrogen gas*
Analysis of Canned ..pp&ijae. Juice
Ascorbic acid*
The retention of ascorbic acid in canned orange
juice stored for 12 months at 3h01> 70° and 110° F tsas 99s 9$ and 31
percent respectively (Figure 8).
Six percent had been retained after
18 months storage at 110° P, -ahen analysis of this group "was disc on*
tinued.
After 2k months at 3It0 and TO0 F. the retention was 9k and
89 percent respectively.
The retention figure at 3k0 F* storage is
lower than for grapofruit juice at this temperature but was higher
at the 70° F. storage*
The loss at 110° F. during the first three
months ^•^as about the same as for grapefruit juice but the rate of
loss was not as great after 3 months storage.
These data indicate
that for orange juice any temperature between 3k0 and 70° F* would
give retention of at least 95 percent for 12 Eionths of storage.
Niacin.
The retention of niacin in canned orange juice (Figaro
9) was almost identical with that reported for grapefruit juice.
The
percent retention after 12 months storage at 3k0s 70° and 110° F*
were 979 97 and 93 percent respectively.
After 2k months storage
at 3k0 and 70° F* the retention was 90 and 88 percent respectively.
As with grapefruit juice9 the retention of niacin does not appear to
be greatly influenced by temperature of storage but does show a
change with time*
As noted previouslyt the score used is deceptive
and the actual loss is not great*
lilt
100
90
ao
STORAGE
70
z
o
p
(oO
TEMPERATURES
^««»A
BA" F .
C«M"»C
TO" F ,
Q^MfcO
MO'F
z
Ul
50
h
z
\
40
30
-
1
to 10
O
9
IZ
IE
MONTHS IN
b
F|G 10
15
STORAGE
18
21
24-
RETENTION OF THIAMINE IN ORANGE JUICE
ISO
so
so
70
40
50
cr -r 0=AG£ TLMPFRA^URES
40
"■4
■ '.
. —».
70° F
^^BL
110° F
30
20
-
10
-
F
1
J
.
I
i
IS
VONTHS
FIGH
X..
21
IN STORAGE
RETENTION OF RIBOFLAVIN
IN ORANGE
JUICE
24-
us
IO0
90
80
2
O
P
Z
hi
TO
faO
tu
a.
SO
h
40
z
u
STORAGE TEMPERATURES
■
30
Q.
0^"i»0
10° F
Qt^mmma
110° r
ZO
10
O
9
MONTHS
FIG. 12
12.
IN
13
STORAGE.
18
RETENTION OF PANTOTHENIC ACID IN ORANGE JUICE
in
u
2.0
|STQRAGE
v>
3
3
-i
2
21
A
TEMPERATURES
A
C-~~"^
L
(U
34° F
TO' F
U0° F
p
in
a
h
Z
ui
ui
K
15
CD
5
<
u.
O
O
b
9
MONTHS
IZ.
IS
IN STORAQE
FIG. 13 CHANGE IN COLOR OF ORANGE JUICE
24-
Thiamlne.
The retention of thiamine by canned orange juice
(figure 10) ^as excellent at 3^° and 70° F,| and the curves fcr
grapefruit juice and orange juice were almost identical*
Howrer$
the average retention was higher at the conclusion of the storage
period in the orange juice*
At 12 jaonthSi, orange juice stored at
5U% 70° and 110° F» retained 98, 95 and 39 percent of the thiamine*
At the lower temperatures^ thianine retention sheared to be in«*
fluenced only by the length of storage Bith 93 a«d 86 percent being
retained at 2h months.
During the first 6 months at XLGQ F» the
loss of thiamine ims very rapid, but became very slow after that
period^ only 10 percent being lost during an additional 12 months
storage as compared to 57 percent during the initial 6 months
period.
liboflavin.
The retention of riboflavin (Figure 11) after 2k
months storage at 3h0 F. was 93 percent as compared to only 79 percent
at 70° F.
Riboflavin appeared to be influenced more by temperature
of storage than by time.
At 110° F. there was a retention of 70
percent after 12 months but aft&r 18 months there was only a 37
percent recovery.
It is interesting to note in this connection
that there was no sudden loss and subsequent increase of riboflavin
in orange juice as reported for grapefruit juice*
Pantothenic acid.
The loss of pantothenie acid (Figure 12)
was more rapid during the first 12 months storage at 3ii0 F* in
canned orange juice than in grapefruit juice.
However^ at the end
hi
of 2k months there was a ?5 percent retention tghich was slightly
higher than comparable grapefruit juice.
Storage of orange ^uice at
70° F* gave retentions of 79 and h9 percent at 12 and 2k months re*
epectively.«
The retention of pantothenic acid stored at 110° F-«
ma 53 and k2 percent at 12 and 18 months respectively.
The loss
of pantothenic acid TOS influenced by both time and temperature.
Change in color*
is given in Figure 13«
The ratio of amber/green tristimulus filters
As with grapefruit juice the individual aaiiber
and green tristimulus filter readings Changed at 3U0J? 70° and 110° F.
There occurred a very slight change in the ratio at 3V3 and 70° F, but
it was never more than 0,10 from the initial reading*
The data in
Table V with respect to U«. S* grade show little variation between
the evaluation of color for 3k0 and 70° F.
At the end of three months storage at 110° F.. the amber filter
reading decreased from the value of the initial reading while the
green filter reading remained constant.
This resulted in a more
narrow ratio between the two filters than in the initial examination*
After storage for six months at this temperature, the green filter
gave increasingly lower readings than the amber filter and the ratio
increased..
Coupled with the increase in ratio of the amber/green
filters were decreasing values assigned for color in U. S. grade.
In this coisioetion it should be noted that the ratio between the
ninth and tt-ielfth month was constant and at the same time loss in
18
340F
70oF
ORANGE
ll0oF
JUICE
STORED 12 MONTHS
JUICE
ORANGE
STORED
Figure lk*
24
MONTHS
Kadachromes of orange juice stored 12 and 21; months
at 31°, 70° and 110° F.
4.9
ascorbic acid was only three percent, A rapid increase in the ratio
between the twelfth and eighteenth month of storage was associated
with a rapid decrease in ascorbic acid.
The correlation coefficient
between loss In natural color * as expressed by the aaiber/green ratio
and loss of ascorbic acid was -0.759*0,122Jn^ 12,
true at ti © 110° F* storage •
This is particularly
£<oss in color was not influenced by
storage temperatures between 34° and 70° F. but storage at temperatures
between 70° and 110° F« would result in increasingly greater loss of
color.
The kodacbrome pictures of the juices after 12 months at 34°^
70° and 110° F, and after 24 months at 34° and 70° F. are presented
in Figure 14.
U. St, grade♦ Storage of orange juice at 34° F, for a period
of 24 months did not lower the U, S, grade as shorn in Table V,
There was a slight change in the points assigned to the individual
grade attributes but these did not influence the final grade. Orange
juice stored at 70° F, remained U, S, grade A until between the
"^
twelfth and fifteenth months when the flavor dropped to 33 points
out of a possible 40,
It is noted that although the total score was
90 points at 12 and at 15 monthss the juice was reduced to U, S.
grade C at 15 months because of the limiting rule for flavor.
The
same was true for'grapefruit except that it was graded C at the end
of 12 months storage.
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Ehe redaction in U», S, grade at 110° F» was not as rapid as in
the grapefruit j-oice.
The orange juice was rated U* S, grade C after
3 months storage because of the rule on flavor*
The color of the
juice at this period was in the lox^sr limit for grade A.
Subsequent
storage at 110° F, resulted in an inoreasingly greater loss of flavor
and a gradual loss in color between the twelfth and fifteenth months
irfhen the juice darkened severely.,
This is in agreement with the
evaluation of color from the amber/green tristinrulus filter ratio*
Although color of the orange juice did not deteriorate as quickly
as that of the grapefruit juice, the orange juice was reduced to
U. S. grade D after 6 months on flavor alone.
Grganoleptic evaluation.
Juice stored 2U months at 3^° F. ms
rated better than the initial sample.
and "very good".
Epical remarks were "eiocellent"
This is not considered significant because the judges
could not be eicpected to make absolutely accurate comparison over such
a period,
A slight but increasing degree of differentiation wts made
in color of the juice stored at 70° F. as time of storage increased.
Flavor received increasingly lower scores and there were comments
such as
M
strong5 tin flavor^ terpene flavor^ off flavor^ old metallic
flavorw with increased length of storage at TO*3 F.
Orange juice stored at 110° F, was severely criticised on color
at 3 and 6 months and flavor of the juice was graded even more severely
at these two periods.
All judges refused to taste the juice after
6 months storage at this temperature.
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52
53
100
30
80
TO
z
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p
z
u
i-
-
GO
STORAGE
SO
TEMPERrtTURES
u
a
^-
z
u
u
SO
-
20
-
\
10
9
IZ
13
MONTHS IN STORAGE
18
21
2.4-
FIG.I5 RETENTION OF ASCORBIC ACID IN GRAPEFRUIT- ORANGE
JUICE BLEND
100
ie
94.
94-
Z
o
p
92
je
90
LI
(k
»z
u
88
TEMPERATURES
A «■■»/_
340F
U^MavD
IIO°F
8fc
UJ
a.
STORAGE
84
82
80
9
MONTHS
IE
15
IN STORAGE
18
21
FIG.IG RETENTION OF NIACIN IN GRAPEFRUIT-ORANGE
JUICE BLEND
IA-
$h
.100
u^
0
pz
^^^
£0
u
1-
lii
50
■
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k
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Id
u
DC
Ul
a.
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"
10
1
18
9
12
IS
MONTHS IN STORAGE
21
z*
RGIT RETENTION OF THIAMINE IN GRAPEFRUIT-ORANGE
JUICE BLEND
too
90
80
STORAGE
TO
z
o
z
u
Yu
2
a
\
<2>0
TEMPERATURES
A
A
3*°F
O
O
70° F
D
□
110° F
SO
40
\
30
QC
EO
IO
_l
____i__!_ ___i.=_
9
li
MONTHS
IN
IS
13
21
STORAGE
FIG. 18 RETENTION OF RIBOFLAVIN IN GRAPEFRUIT-ORANGE
JUICE BLEND
2A
55
Analysis of Canned Grapefruit«>C^an^e Juice Blend
Ascorbic acid.
The retention of ascorbic acid by the citrus
blend stored for 2U months at 3k0 and 70° F. (Figure 15>) was not as
good as that for grapefruit or orange juice *
After 12 and 2h months
at 3h0 F. there was 9h and 88 percent retention as coiripsred with 88
and 68 percent at 70° F,
After 12 months storage at 70° F, the
slope of the retention curve became steeper than during the first
12 months.
At 110° F. retention of ascorbic acid after 3 and 6 months
x-jas h9 and 18 percent respectively.
Analyses for ascorbic acid in
blend stored at 110° F. were dropped after 6 months storage.
Hiacin.
The retention of niacin by the citrus blend (Figure
16) was simlar to that of grapefruit and orange juice*
Temperature
did not appear to influence the retention as did length of storage.
After 12 months the retention of niacin tras $$s 96 and 92 percent at
temper attires of 3^°* 70° and 110° F.
After 2k months 91 and 90 per-
cent were retained in continuous storage at 3^° and 70° F* respec*
tively.
There appears to be no heed for refrigeration for retention
of niacin in either the blend or the pure citrus juices.
Thiamine.
The retention of thiamine in citrus blend was more
favorable after 2h months storage at 3k0 and 70° F. than for either
grapefruit or orange juice.
After 12 months at 3k0* 70° and 110° F.
grapefruit*orange juice blend retained 99f 9h and US percent respect
tively of the initial thiamine content (Figure 17)*
After 2k months
98 and 88 percent of the thiamine was retained at 3U0 and 70° ¥,,
56
h^6:
loo
»<&
so
o.
80
z
o
D
70 t-
STORAGE
TeMPFKATURES
S.m^mA
34° F
^■■■■■c
IIO'F
&0
2
Li
tUl
50 -
\
a;
h
4-0
z
30 UI
a
20
10
.1
6
1
9
MONTHS
J
i
1
ia
IN
is
18
21
24-
STORAGE
FIG.I9 RETENTION OF PANTOTHLNIC ACID IN GRAPEFRUIT-ORANGE
JUICE BU NU
tn
I.S
1-
I.&
!
I.S
>-
/
3
J
5
I-
7
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a
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1.3
{-
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1.0 S-
'<&'
STORAGE-
•d
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ID
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,&,
TEMPERATURES
U"*"»0
U«MML.
2
'fe«
700F
IIO°F
.lb
<
5
9
MONTHS
3
FIG 20
CHANIGT
«
IN
15
STORAGE
ia
IN COLOR OF GRAPEFRUIT- ORANGE
JUICE BLEND
*<&
$1
!Phere was a loss of 3k percent in thiamine during the first 3 months
at 110° F»
Continued storage at this teraperatiire for an additional
15 months resulted in a further 29
percent loss*
It ffiEgr be seen flrora
Figure 1<? that the most critical period for thiamine xms during the
first three months of storage at 110° F*
Riboflavin.
The retention of ribofla-iiln by the citrus blend
stored at 3h0 and 70° F. v&s practically identical at the conclusion
of the storage period (Fig\ire 18) to that reported for grapefruit and
orange juice.
At 3h0 F. retentions of 95 percent or more were found
at all tiiaes during the storage period*
During the first 12 months
at 70° F. the riboflavin gradually declined to 93 percent*
additional 12 months ttor© tms a retention of h9 percent.
After an
It x^as
apparent that the loss of riboflavin ms more rapid during the second
year of storage than in the first 12 months at 70° F.
The influence
of 110° F, storage on retention of riboflavin ms striking in tlmt
there occurred a relatively steady decline of 10 to 15 percent during
each three month period up to 12 months*
From 12 to 15 months 20
percent additional was lost and from 15 to 18 months only 8 percent
loss occurred.
These high storage temperatures are accepted as very
detrimental from the standpoint of riboflavin as well as other attri*.
butes*.
Pantothenic acid*
The retention of pantothenie acid in grape~
fruit~arange juice blend (Figure 19) was influenced by both time and
temperature*
After 12 months storage at 3h0 f,t 72 percent ms
£fc
IIOwl
GRAPEFRUIT—ORANGE
JUICE
DLENO
STOR ED
Figure 21.
MONTH
KodachromeB of grapfriait-crange nuice blend stored 18
and 2h months at 31°* 70° and 110° F.
59
retained as compared to $6 percent at ?00 F? sad 37 percent at 110° F*Only kh percent was retained during th© first 9 months fet HO0 P. in
the blend as compared to 62 percent in grapefruit jtjice and 6? percent
Storage for IS months at teraperatures betoeen 3h0 and
In orange jtdce«
70° F* Fill resialt in 90 percent or better retention of pantothenic
seid.
Change in color,. The ratio of the anber/green tristimul^ts filter
did not change materially during the storag© period (Figure 20) at
3^° and 70° F*
1*05*
At the tin© of the initial ©xaraimticn the ratio ms
Storage at 3h0 F» for 12 Months rave a ratio of 1*03*
ratio, 1*03 ^as also found at 3* SI and 21* month© at 70° Tt
The
There
can be no significance attached to this difference^ hot-jever^ because
the instrument used was not accurate to such a degree*
The color
ratio increased during the first 6 Months of storage at 110° F*5 then
tended to level off for 3 rooaths after which it iaereased very rapidly
from 9 to 15 months*
Figure 21 depicts th© color of grspefruit-orange
juice blend after 18 months at the three temperatures and after 2h
months at 3h0 and 70° F*
A correlation coefficient of *0«936- G*0£Q
was obtained between loss in color and loss of ascorbic acidi
XJi S*. grade.
n** 8».
The change in U* S* f?rade is presented .according
to individual components in Table ¥11*
As with grapefruit and oran're
juice^ storage of the citrus blend at 3k0 F* for a period of 2k snonths
did not reduce the juice below an A grade prodiact*
is mth grapefruit
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61
62
juicej the score for color did not change materially during the 2h.
month period of 70° F. but change in flavor reduced the juice from
grade A to G after 12 months storage.
From 12 to 2k months the juice
remained Ut S, grade C on flavor alone and the score for flavor de«
creased progressively to a low of 28 between 18 and 2k months.
Stored at 110^ F, the blend depreciated rapidly.
storage color was at the lower limit for grade C,
was graded D because of flavor*
After 3 months
The juicej however,
In this instance the grade was dropped
from A to D in 3 months at 110° F. because of flavor alone.
At 6
months the color had changed radically and there were no points as*
signed.
The absence of defects attribute of the grade did not change
during this period.
It is interesting to note that judgement of
color in U. S. grade decreased in proportion to the increased filter
ratio as shown in Figure 20.
Organoleptic evaluation*
The data presented in Table VIII show
that the panel of judges did not differentiate between juice stored
at 3k0 F. on any of the periods of examination.
The acceptability
was as good at the end of 21; months as on the initial examination.
I^pical remarks of the judges of the blend stored 2k months at 3k0 F«
were "very^ very good juices e3£cellentl,,.
There was discrimination against the color of the juice stored
at 70° F. bettfeen 18 and 2k months although the range at this time
was "good to very good".
When the judges were asked to evaluate the
juice for flavor;, the scores assigned decreased regularly from the
63
ninth to the twenty^first month but thereafter the points remained
almost constant.
The judges commented on the fact that at 9 months
the juice was "'astringent^, terpene5 bitter, metallic"*
typical comments weres
At 2h months
"strong and terpene"*
Juice stored at 110° F» lost color and flavor very rapidly in
3 months*
At the time of the initial examination the Color judgement
averaged 8,3 (very good) and for flavor 7*9 (very good).
The same
judges rated the color after 3 months at 110° F. as 3»9 (fair) and
flavor 2.£ (poor to poorly fair).
After six months storage the juice
txas rated as repulsive*
Analysis of Canned Grapefruit Sections
Ascorbic acid*
The retention of ascorbic acid in canned grape*
Retention after 2h. months at
£ruit sections is shoxim in Figure 22*
311° F. tjas greater than that for the blend and slightly belotf that of
At 3U0 F. retention was 96 and
straight grapefruit or orange juice*
93 percent after 12 and 2k months storage respectively, compared to
12 and 20 percent for the 70° storage.
The greatest loss at 70° F.
occurred during the first 9 months of storage when 11 percent of the
vitamin had disappeared.
A retention of $9$ 26 and 11 percent was
noted at 3? 6 and 9 months of storage at 110° 5;.
occurred during the first 6 months*
The most rapid loss
The retention of ascorbic acid
in citrus sections stored at temperatures between 3U0 and 70° F,
could be expected to be at least 88 percent after twelve months of
storage.
6k
z
g
i--
z
STORA&F
a)
I-
9
It
MONTHS IM
TEMPERATURES
(^ MMiaB ^
70° F
IS
STORAGE
18
FIG.22 RETENTION OF ASCOfBC ACID -N SRAPLFKUr SLTTIONS
100
'V^
9a 96 -
z
94 -
z
u
92 j-
STORAGE
^
TfcMPnf?ATURE5
'iA -TO' r
MO* F
/,'
0
V-
90 i-
z
u
ti
u
a.
1
88 I
86
.
84-
-
82
-
SO
JL.
I .
9
MOMTHS
IZ
15
IN STORAGE
24
18
FIG. 23 RETENTION OF NIACIN IN GRAPEFRUIT
SECTIONS
65
90
80
z
o
i2
K
\
-
STORAGE TEMPERATURES
A *■»•_'..
34 T
C «■■■».70° F
■^mimmm^ 110* f
TO r
60 ■!■
1u:
a.
l-
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u
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50 j
«
40
H
1
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30 j-
zo
10
■
o
MOWTHS
I
12
'M
18
15
STORAGL
FIG. 2.4 RETI'MTION OF THIAMiNE IN GRAPtFRUIT
21
24-
SFCTI0N5
100
^"^^asw.;
z
o
h
Z
h
2
• Li
<_
a.
90
,-
80
-
70
-
60
-
50
-
40
i-
30
!■
\
STORAGE TFM'PERATU
A^i^B^ 34° F
Cmmmm^ 7o° F
z^immmZ
c
110° F
lu
Q.
20 I-
\
10
o
9
12
MONTHS IN STORAGE
FIG.25 RETENTION OF RIBOFLAVIN
15
18
IN GRAPEFRUIT SECTIONS
t4-
66
Wiacin«
The retention of niacin in grapefruit sections (Figure
23) was 93 percent when stared 12 months at $h0 F*
Siis trjas lower'
than that for other citrus products after 12 months storage.
After
ik months at 3UQ F. the retention was 6 percent lower than that reported for grapefruit juice.
The saKte was true of storage at 70® F.
At 12 and 2h. months the retention of niacin was lo*?er than that re»
ported for other citrus products.
The rate of decline uas more rapid
in sections than in the other products*
The only difference between
the products was the higher degree Brix of the sections*
Attention
is called to the deceptiveness of the scale used for niacin,
Thiamne»> The retention of thiaraine in grapefruit sections was
not seriously influenced by storage at 3h0 or 70° P.
After 2h months
at these two temperatures 96 and 92 percent were retained (Figure 2k)*
After 2k months at 3k0 F. 'the retention tras lot-rer than for the blend
but higher than grapefruit or orange juice.
At 70° F., the retention
at 2k months tjas higher than in any of the other citrus products.
The effect of storage at 110° F. t-jas less striking than for other
citrus products but in any case, bears out the fact that thiardne is
not favorably retained in citrus products at .high temperatures.
Temperatures between 3k0 and 70° F* have negligible effects on the
vitamin.
Riboflavin.
The retention of riboflavin (Figure 25) t-rets
88 percent after 2k months at 3k0 F.
At both 12 and 2k months
67
grapefruit sections contained less riboflavin than the other citrus
products.
At 70° F«3 there ms less riboflavin at 12 and 2^ months
but the difference in retention between the sections and the other
citrus products ms less noticeable than at the ^k0 F* storage.
HO0 F» the loss was more rapid than for other products*
At
¥ith a
retention of 86$, 67<> kh and 19 percent of the initial riboflavin
content at 3a 69 9 and 12 months respectively*
Pantothenic acid*
Hhe retention of pantothenic acid (Figure 26)
was about the same after 2k months storage at SU® and 70® F* as for
other citrus products.
At 110° F.^ the rate of loss during the first
6 months was double that of other citrus products.
After 6 months
the rate of loss "ssas about 10 percent for each 3 month interval,
Pantothenic acid is mfluenced by both tine and temperature sri/th
temperature escorting a more detrimental effect.
Change in color*.
Change in color of grapefruit sections after
2h months at 3^° F* (Figure 27) ws about the same as for other citrus
products at this temperature,
Although the refleetometer readings '
varied xclth time, the ratio between the amber/green tristimulus fil«
ters did not change,
Hie filter ratio at the beginning of the storage
was 1,00 and did not Change materially throughout a 21* month period.
In general, the filter ratio from sections stored at 70° F. increased
t-iith duration of storage.
The change t^as not great but detectable
as may be seen in Figure 28,
At 110^ F. there was only a slight
change in the ratio during the first 3 months.
Subsequently there
68
z
Q
h
z
y
i-
u
K
I2
STORAGE
hi
&
Id
30
20
TEMPtRATURES
—"^■■•i.
3^'F
^.^■"■"-v^
^O'F
rj—"mm,-_
|tO°F
r
I
10 h
O
(
1
—
9
KtONTHS
12
15
IM STORAGE
. ;'i8.
21
24-
FIG.2& RETENTION OF PANTOTHENIC ACID IN GRAPEFRUIT SECTIONS
STORAGE
I.&
TEMPERATURES
1.5
in
-I
1.4
I
h
1.3
I-
a:
<
u
m
<
o
/
1.0
0.9
0.8
0.7
9
MONTHS
12
15
IM STORAGE
IS
FIG.ZT CHANGE IN COLOR OF GRAPEFRUIT SECTI0M5
a*
69
Figure 28.
KodachromGS of grapefruit sections stored 12 and 2k months
at 3k0, 70° and 110° F.
70
tias a yery rapid increase #iieh' agreed mth the visual color evalu-^
ation and deer ©as© ±n U* B». grade*
ifter 3 laonths- at 110'° ?«,, the sections has lost ill percent of
the ascorbie acid and the poisats assigned for color score in L.. So
grade declined U poiats.. Coupled tsith these decreases tras an in*
crease ia the value of the assber/green ratio fross 1*00 to l*0k«
After 6 months there was a loss of ?l& percent of the ascorbic scidj
the color score ms 0 and the filter ratio increased'to !*§$.
The
correlation coefficient betesen change ,111 color and loss of ascorbic
acid in grapefruit sections t-jas «=O»9C0tC*c66s ns* 8»
U» S* grade*
She grade for grapefruit sections includes?
drained neiphtf, t&oXeneecj color9 absence of defects ami character
of fruit*
There are three grades*
Each of the attributes of grade
are assigned 20 point® in the grading systera.
Asgr grade factor .
given a value of befrKeen 15 and 17 points iaelusive limits the pr©~
duetjj regardless of total score to U* 5* grade B*
If the ©cor©
assigned is between 0 and lU inclusi^ire the grade autoBtatieaMy
becomes D or off grade*
During 2k months storage at 3h0 Wb^ there t-;ere practically no
changes in points for various attributes of TJ» S* grade as my be
seen in fable Hi
period;
The sections remained U* 'S* grade l for the entire
It 70° Fis there tjas found a progressive decrease in drained
weighty color and character of fruit up to 2h months*
The fruit
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73
softened and the drained t-jeight decreased tdtfo time.
After 12 months
the sections were U* S. grade B on the basis of color.
After 15 months
they were grade B not only on color but on drained weight and character
of the fruit,
M the end of 2k months at 70° F, sectiona were easily
brokenji an intact section could not be lifted with a spoon.
The
effect of refrigerated storage on the character of fruit -ms particularly noticeable.
After 3 months at HO0 F.^ the fruit ms U, S4 @?ade D on the
basis of character of fruit x-jhich was below the limitations«
At 6
months the character of fruit factor had been seriously degraded but
drained x-reight and color also influenced the off-grading of the pro*duct.
This is in agreement with the rapid increase in amber/green
filter ratios*
At 9 xnonths storage., in addition to colorj drained
weight, and character of fruit., the wholeness factor entered into
the attributes causing the down grading of the product,
The influence
of high temperature storage of citrus sections was very striking in
relation to quality attributes of the U» S. grade*
Qrganoleptic evaluation*
The judges did not note any particular
change in the sections stored at 3ii0 F,9 during the 2k months storage.
Typical remarks weres
"very good,, fine! bright Color."
On the other
hand there was discrimination against color, flavor and acceptability
of sections stored at 70° P..
The judges became more critical of these
factors as the period of storage increased.
Table X shows a serious
devaluation in color between the 18 and 21 months period at which time
Ik
the filter ratios increased to the highest level.
Ther© x-ras discrim*
ination against the flavor beginning at the ninth month examination
and this factor decreased progressively mth duration of storage*
Remarks on sections stored at 70° F. t-ieres
"slight can flavorj metal
flavor, terpene beginning (9 months)% slightly yellow5 terpene devel«»
oping (12 months )j beginning to break dot-m (at 15 months which corses*
ponded to the U, S* grade limitation for character of fruit at this
period)j metallic flavdr (18 months )j poor flavors. strongg, too soft
(21 months) and too darks liquor darks much breakdoi-m (2k months),"
The judges refused to sample the sections after storage for 9
months at 110° F*
Color,, flavor and acceptability were below the
acceptability level at 3 months storage.
the U. S* grade D at this t±rmf.
this period were?
This was in agreement with
The remarks of the judges during
?,
off color and very pronounced can flavor (3 months)
and very poor, repulsive flavor and color3 mushy8' at 6 aaonths storage.
Analysis of Canned Tomato Juicft
Ascorbic acid.
The retention of ascorbic acid (Figure 29) after
12. and 2k months at 3^ F« was 97 and 92 percent respectively*
The
percent reduction at 3k0 F, was about the same as that in citrus
products*
The grapefruit sections, however, retained less after 2k
months than did the tomato juic©»
The retention of ascorbic acid at
70° F. after 2k months storage was higher than that found in all citrus
products with the exception of the orange juice♦
The loss of ascorbic
acid at 110° F. did not take place as rapidly as in the citrus products.
IS
100
N
90
-
80 r
z
o
\z.
Ui
1-
70
feO
hl
u.
50
_
t1
40
„
Ui
30 20
-
\0
-
« L9
12
15
MONTHS IM bTORAGE
IB
FI&.23 RE TEMT ION OF ASCORBIC ACID IN CANNED TOMATO
100
21
24-
JUICE
,
98 ~
9fo r
z
o
yz
u
(-
q4
-
92
"
90
r
ea
-
8<b
-
u
o:
l-
z
1U
u
DC
14
a.
STORAGE.
TtMPCRATURCS
C aMn»(
70 K
.. «MM» : I
II0 ' F
84
U2.
'■ I
80
i
i-
9 .12
15
MONnlS IKJ STORAGE
18
FI&. 30 RETENTION OF NIACIM IN CANNED TOMATO
21
JUICE
~""Z4-
76
Miere the. range in percent retention in citrus products was h9 to 62
after $ months* toinato juice retained 71 percent. At 6^ 9> 12 and 1S>
months storage at 110° F.* tomato juice retained SS9 kZf 31 and 15
percent respectively. Analysis at the 110° F* teraperat-ure tjas dis*
continued after 1^ months*
Hiacin.
The retention of niacih in canned tomato juice stored
at 3h® ■F«--was excellent (Figure 3©)* After 2h months^. 92 percent of
the' initial content t^as retained*
This agrees favorably with the
retentions reported for the citrus products at 3h0 F, with the escception of the grapefruit sections. After 2k months there appeared
to be a very slight influence of the 70° F* storage on the retention
of niacin but the loss was not nutritionally significant*
Kiacin was
not affected by 110° F. storage during the period of shelf*life*
Thus
after 18 months at 3h0i 70° and 110° F. recoveries of 9k^ 9h and 90
percent of the initial niacin content were obtained*
Thiamine*
The retention of thiamine by canned tomato juice
was higher at the completion of 2k months storage at 3k0 F* (Figure
31) than the recoveries obtained from grapefruit or orange juice.
2k monthss 96 percent of the original content was found*
At
After 2k
months at 70° F*, retention w&s equivalent to that of citrus products
being 93 and 87 percent respectively after 12 and 2k months storage*
The loss of thiaraine in tomato juice stored at 110° F* was not as
rapid as the losses experienced in citrus products. At 3* 6* 9*
12, 15 and 18 months at 110° F. the recoveries were 90^, 809 129 58^
77
S>3 and 3h percent respectively.
As a comparison tomato juice re-
tained 80 and 58 percent at 6 and 12 laonths while grapefruit juice
retained III and 3li percent,
Riboflavin.
The retention of riboflavin (Figure'32).was 92
percent after 2h months at 3k0 F.
This compares favorably with that
of citrus products with the essception of the sections which were lower
in the vitamin.*
recovery.
After 12 months at 3h0 F» there x-aas a 97 percent
After 12 and g'ii months at 70° F* the respective recoveries
were 90 and 81 percent,
The retention at 2k months xms about equal
to that reported for all citrus products ezcept the grapefruit sec*>
tions which were lower at this period.
The rate of loss of riboflavin
at 110° F, was of about the same magnitude as that reported for the
retention of thiamine in tomato juice,
Pantothenic acid,
Pantothenic acid in tomato juice appeared
t© be Influenced by both temperature and length of storage.
As
temperature and time increased there was progressive destruction of
pantothenic acid.
The loss at 3k0 and 70° F, xras ©imlar for the
first 6 months but with combined storage there was a greater loss at
70° F. than at 3h0 F. (Figure 33 )<
After 12 and 2h. months at 3U0 F,
th© retention was 89 and 72 percent as compared to 79 and 55 percent
at 70° F,
The rat© of loss of this vitamin in tomato juice stored at
110° F, xms similar to the citrus products except the sections which
gave a lower recovery than did the tomato juice.
78
100
90
80
z
o
p
z
70 i-
so -
Li
t
t-
u
so -
t-
4-0 -
2
u
K
STORAGE TEMPERATURtS
\
.'.mtmmm/. 34- F
y
30 sUmmm^u uo°F
a.
ZO 10
, .1
9
MONTHS
, l
'
\Z
15
|W STORAGE
1
IS
1
■_
Z4-
2)
FIG. 31 RETENTION OF THIAMINE IN CANNED TOMATO
JUICE
100
90 80 2
O
h
70
-
£0 -
(lu
Of
z
UJ
111
a
50 '
40
-
30 f-
STORAGE
TEMPERATURES
AmmmA 34'F
0«w»0 70° r
U«HI^U II0°F
io i10 h
9
12
IS
MONTHS IN STORAGE
24-
IS
FIG.32 RETENTION OF RIBOFLAVIN IN CAMMED TOMATO
JUICE
79.
100
'©J
•A,
90
>Ci
80
z
o
£
•■A,
70
-
Ul
60 i1
or
50 j.
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STORAGE
-TEMPERATURES
&mmm&
30
34-" F
C«M»U 70" F
■
D«Ha»Q
no'
F
20
10
■
O
9
12
•
IS
MONTHS IN STORAGE
B
24-
21
FI6.33'RETENTION OF PANTOTHENIC ACID IN CANNED TOMATO JUICE
14
in
J
3
Iv)
S
(2
y
Li
m
2.
<
<
9
M0WTH5
FIG. 34
CHANGE
2A
12
15
IN STORAGE
IN COLOR
OF CANNED
TOMATO
JUICE
80
Figure 35.
Kodachrones of tomato juice stored 12 and 2h Jnonths
.at 3ii0, 70° and 110° F.
81
Change in color.
The color of canned tomato juice during 2h
months storage at 3h0 and 70° F., did not change as shot-m by the
ratio of the awber/'green tristimulus filters (Figure 3h)<>
The in-
dividual filter readings varied with tirae but there was no consistency
in the direction of change.
The range of differences tras of greater
magnitude with the amber filters than with the green filters,
l-Jhen
stored at 110° F,,. the ratio of the filters increased from 1*8? to
2*17 at 6 months storage. , This was due to an increase in the amber
reading at 3 months with no change in the green filter.
At 6 months
the. amber filter reading x-sas the same as the initial reading but the
green filter readirig decreased-.
This condition was responsible for
the rapid rise in the ratio during the first 6 months of storage.
The data reported in Figure 3h indicate that at 9 months storage
there was an abrupt decrease in the ration to a point lower than the
initial values.
This corresponds to the abrupt* drop in points assigned
for color in the U, S, grade (Table XI),
The decrease in ratio Was
due to a lower araber reading while the green reading remained constant.
The subsequent decrease in the ratio was due to a greater increase in
the aTaber than in the green filter but the ratio was less.
Visual
inspection of juice stored at 110° F. showed a gradual darkening with
red and brown colors predominating (see Figure 33>),
during the first 9 months.
This occurred
Thereafter there appeared to be a great
deal of yellow in the reflectance which gave a yellowish brown cast
to the tomato juice.
The loss in color expressed by the amber/green
St
6
9
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82
83
tristiroulus filter ratio ms more closely associated mth the loss in
thiaraine than irith the other vitamins.
There appeared to be no asso*'
ciation bett-ieen ascorbic acid .content and filter ratio in tomato
products.
U. S. grade.
The attributes of U. S. grade for canned tomato
j-uice are color^ consistency^ absence of defects, and flavor.
The
most izaportant factor in grade is flavor (UO points )S) follot-jed by
color (30 points) and consistency and absence of defects (15 points
each).
The toisato juice was U. S. grade A at the beginning of storage
and at 3^° and 70° $,9 the total points assigned did not change during
2h months storage (Table XI)>
It appears that little would be gained
through storage of tomato juice at teinperatures lower than 70° F, as far
as U. S. grade is concerned.
This is in contrast to the situation t-jith
respect to citrus products where flavor was the prime factor in loss
of g^ade.
During the last 9 months of storage at 70° F. the average
score assigned for flavor of tomato juices was slightly higher than
the score for the 3hQ F* juice.
After three months storage at 110° F,« the juice was U. S. grade
C because of a limiting rule for color.
At this time the ratio had
started to increase and the juice was reduced by 2 points.
At 6
months the color ratio had increased to its highest level and the
juice was reduced by an additional 2 points but was still U,f S. grade
C on the basis of color.
The ratio of the amber/^een filters de-
creased very abruptly at 9 months.
Coupled mth the sudden decrease
1
!
fot'
o
6i
ON
•9
3
•ri
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p^
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cf>r^«>»4'HOv9r*ll-^
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81;
85
was a loss of 9 points in evaluation of color for U* S. ^ade resulting
in tomato juice of U, S. grade D (off*grade).
With respect to flavor^ juice stored at 11O0 F* shcn-jed a rapid
loss in points»
At the end of 3 months the points had decreased fcy
11 while at 6 months there taas a decrease of 27*
It is apparent from
Table XT that the flavor factor undergoes the most rapid change.
At
temperatures between 70Q and 110° p. color changes somex^hat during
the first 6 months but the greatest change is in flavor which alone
produces an unmarketable product.
Continued storage at 110° F, mil
result in deterioration of both color and flavor to grade D*
Organoleptic Evaluation.
Table XII gives the results from
the panel of judges on the general quality level of canned tomato
juice.
The judges discriminated slightly against color of juice
stored at jk® f*
Flavor of the juice ms also graded down after the
first 3 months but there occurred very little change mth subsequent
examinations.
The remarks given on tomato juice stored at 3^° F. were
in general "ra% good but slightly raw flavor".
When the juice was
stored at 70° F. the judges believed the color and flavor tfere
slightly better.
At If? months they remarked that the juice had "a
pleasing salty after taste 'which is not true of the juice stored at
31*° F.".
Continued tasting of tomato juice stored at 70° F* resulted
in the same typical remarks.
The judges did not taste the juice stored at 110° F* after 9
months and at the 9 month interval only one judge would do so$
86
L—**—*■!
■*.
1H
STORAOr TtHPLRATURES
2
hi
t-
: mimmU 34° F
. MOTVv. 70° F
ID
a.
UOHMWD MOV
I
UJ
a
_ _L
_
>
.
I
9
12
15
MONTHS IN STORAGE
IS
Z\
TA-
FIG. 3& REFENTION OF ASCORBIC ACID IN CANNED TOMATOES
100
39
98
2
o
\-
2
96
LI
I-
a.
95
I-
"t
LJ
2
Ul
bi
93
-
9Z
»•
91
t-
90
STORA&C TEMPTERATURES
LmmtmL 34-F
v. ^M»C 70* F
LJaiM*U
HO'F
3
MOMTHS
FIG. 37 RETENTION!
U.
IS
IN STOPAGC
IS
21
OF Nl ACIN IN CAMMED TOMATOES
Z4
87
therefor®, the points assigned at 9 months (Table XII) are not
conclusive*
The judges degraded the color but they did not degrade
it as seriously as the flavor*
The rapid decrease in flavor evalua*.
tion was in agreement with the points assigned to flavor by the U» S*
grade.
At 3* 6 and 9 months the remarks on juice stored at 110° P.
•Here "soapy flavors caramelised flavor developing and poor!'5*
It
was apparent that 3 to 6 months storage at 110° F* would seriously
influence the quality of canned tomato juice as far as a taste panel
is concerned.
Of even greater importance is the decrease in U. S.
grade and the concurrent economical loss.
Analysis of Canned Tomatoes
Ascorbic acid*
The retention of ascorbic acid in canned tomatoes
(Figure 36) tras higher by two percent after 2li months storage at 3li0 F.
than in tomato juice.
After 12 and 2\x months tomatoes retained 99 and
9h percent respectively as compared to 97 and 92 percent in tomato
juice.
At storage temperatures between 3k0 and 70° F.^, the retention
of ascorbic acid in canned tomatoes should be 90 percent or more after
12 months of storage,
At 110° F, the rate of loss of ascorbic acid was not as rapid
during the first 3 months of storage as that in tomato juice but with
continued storage loss was ntuch greater.
Tims there was 83<> iil5 23
and 10 percent recovery in tomatoes after 3j 65 9 and 12 months as
Compared to 71? 55> k2 and 31 percent for these periods of storage in
tomato juice.
88
Hiacin*
The retention of niaein in canned tomatoes (Figure 37)
ms not influenced bsjr temperature "but was affected by the period of
storage«
However^ time ms of minor importance and it is concluded
that refrigerated storage t-jould be of no practical importance for the
retention of niaein in tomatoes<►
After 2h months at 3k0 F« and at
70° F,. there t-as 90 said 91 percent recovery of niacin»
Miacln de*
terminations on tomatoes held at 110° F.. were discontinued after 18
months storage.
Eomvrers at this time there xms 93 percent recovery
as compared to 9h percent from tomatoes held 18 months at 3k0 and 70° F.
Thiamineo
The retention of thiamine in canned tomatoes (Figure
38) t«as not as efficient at the three temperatures of storage as
was true of tomato juicet
Retention tras influenced by both tempera*
ture and duration of storage.
After 12 months storage at 3li0> 70°
and 100° F, recoveries t-jere 90^ 81 and 27 percent*
Thiamine determi-
nations were discontinued at 18 months on tomatoes held at 110° F.
After 2h months recovea?y of thiamine from tomatoes held at 3ii0 F. was
86 percent as compared to 77 percent at 70° F* storage*
It should be
noted that there was 10 percent less retention in tomatoes at 3^
and 70° P* than in tomato juice after Si* months storage*
Riboflavin*
The retention of riboflavin in canned tomatoes txas
essentially the same as that found in tomato juice (Figure 39)*
After
3 months storage at 3hQ F*, the loss of riboflavin was gradual and at
a ■uniform rate amounting to approximately one percent for each period
of analysis.
Thus 93 percent recovery was made after 2k months
89
100
z
o
F
z
u
feO -
y
50 -
I-
t-
zlit
tu
0.
40
STORAGC
-
TEMFEPATURCS
A ■■■■>/.
34° F
C ■■■■(_
70 JF
iO -
zo 10
-
O »-
9 .
14
:
MOMTHS iN STORAGE
FIG. 3S RETEMTION OS THIAMINE IN CANNFD TOMATOES
zg
2
U
I0O
^^_
90
r
90
j-
70
t-
fcO
-
50
,_
K.
(-2
40
^U)
i-
STORASC
U
■,
30
r
»o 70° r
|
0.
20
h
10
h
0
TCMPERATURE5
m- 34°F
■«.,
—=^^:
SiO F
^ _l .
9
li
IS
MONTHS IN STORAGE
IS
Z4
FIG. 39 RETENTION OF RIBOFLAVIN IN CANNCD TOMATOES
90
Storage at 3h0 F*
At 70° p*, a X$ month period was equivalent to
2I4. months at 3U0 F»
Canned tomatoes retained 89 percent riboflavin
after 21* months at 70° F* as corfipared to 93 percent at 3hP F, storage.
The loss of riboflavin in tomatoes held at 110° F* was of the same
magnitude as that reported for tomato juice.
An average of 10 percent
riboflavin t-jas lost at each examination.
Pantothenic acid.
The retention of pantothenic acid (Figure
k0) in canned, tomatoes tjas almost identical t-Tith that reported for
toraato juice.
The retention was influenced by both temperature and
duration of storage.
At 12 months the recoveries were 85^ 80 and
61 percent from tomatoes held at 3h0$ 70° and 110° F. respectively.
An additional 6 months storage at 110° F. reduced the vitamin to 1*6
percent <Nhile an additional 12 months at 3ii0 and 70° F* gave 71 and
5>8 percent recoveries*.
With 12 months or longer at temperatures
between 3k0 and 70° F. not more than 80 percent recovery of pantothenic
acid could be expected from canned tomatoes.
Increasing temperature
above 70° F. mil result in increasingly lower recoveries of this
vitamin*
Change in color.
The initial ratio between the amber/green
tristimulus filter readings on canned tomatoes (Figure I4I) was l»9h»
Storage at 3h0 F; gave only a slight variation from this figure«
During the first 15 months period there was a slight but steady de~
cline in the ratio indicating some "yellowing".
This was a result of
interrelated changed in amber and green reflectancej, the greater
91
90
i&*
>Ai
I A.
z
o
yZ
u
I-
Ll
K
H
z
STORAGE
lu
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or
30
lu
a
-ETMPERATURES
■».'
24 F
■•v.
■»'J
70' F
110 F
?0
10
o
Q
IE
IS
MOMTHS IN STORAGE
FIG. 40
Z4-
IS
RFTENTION OF PANTOTMLNIC ACID IN CANNE D TOMATQFS
?.o
►A.
10
QC
111
>J
k
3j
3
l.<3
1.8
STORAor
1.7
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9
MONTHS
FIG.
41
1
i
li
lb
IN STORAGC
1
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1
El
CHANGE IN COLOR OF CANNED TOMATOf S
ZA
92
Figure lj.2,
Kodachronies of tomatoes stored 12 and 2\x months at
3h0, 70° and 110° F.
CD
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reflectance from the green filter creating a condition -which caused
a shift from the typical tomato color to a greater concentration of
yellow units*
After 1$ months the Change vias in the opposite direc-
tion resulting in a product more typical of the tomato*
Regardless
of these changes in reflectometer readingss the color of the tomatoes
held up well on the basis of visual judgement m points assigned for
color in U« S« grade (T&ble XIII) and the evaluation of the "judges
(Table XIV),
Tomatoes stored at 70° F, showed a general aad steady decline
in the ratio throughout the storage period.
It is believed that the
slight variations in the ratio ^hich occurred during storage at 3h0 F.
and 70° F, xaere primarily due to sampling error and the fact that the
product taas not conffliinuted until the time for the color evaluation.
In tomato juice the product wa& eomfflinuted at the time of conning.
The slow but steady decline in color agrees tjell mth the evaluation
of color for U, S, grade but ms not in agreement with the evaluation
for color by members of the judging panel*
There vaB a very rapid loss in the color as ©ispressed by the
ratio of the araber/green tristimulus filters when the tomatoes were
stored at 110° F.
Coupled with the narrowing of the ratio i^as the
increasing development of a dark yellow-red or brown color*
This
was severely discriminated against by the judges and in the official
grade (Tables XIIIa XIV and Figure ii5).
The ratio dropped very
quickly and associated with this decrease was the loss in ascorbic
g
12
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95
96
acid (Figure 36).
The evaluation of color in canned tomatoes by
means of the amber/green ratio did not follow the same trend as that
for tomato juice in that x&th the latter5 the ratio increased for 6
months and then abruptly narrowed*
U. S, grade.
ares
The attributes of the U* S. grade of canned tomatoes
drained weight (20 points)s wholeness (20 points),, color (30
points) and absence of defects (30 points)*
During the storage period
of 2I4. months at 3h0 F. the product changed only a few points in ai$r
of the factors.
These changes did not affect grade of the product
from the Initial U. S. grade B.
The canned tomatoes were U. S. grade
B because of the limiting rule on color.
Storage at 3U0 F. for 2h
months can be expected to cause no change in grade.
liJhen the tomatoes were stored at 70® F.s they remained U. S.
g^ade B for 12 months.
At 1$ months they were U. S* grade C because
of the limitations of the wholeness factor.
enough for U. S. grade B.
The total score was high
Continued storage beyond 15 months resulted
in reduction of the drained weight and wholeness factors.
At 2k months
the wholeness and drained weight factors resulted in U, S« grade C,
As with the citrus sections tomatoes could not be lifted with a spoon
without excessive tearing and the product was very soft and unappealing.
At 110° F. storage there was a decrease in U. S. grade fl-om B
to D in 3 months because of color limitations.
During the 3 months
Storage,, the wholeness and drained weight factor decreased somewhat $
the latter more severely than the former but the primary grade
97
attributes resulting in grade reduction ms color.
After 6 months the
tomatoes were seriously affected.
Qrganoleptic evaluation*
The judges could not distinguish be*
tt-reen the color of tomatoes stored at 31*° and 70° F. as evidenced by
their scores in Table XI?*
Mien asked to evaluate the tomatoes held
at these two temperatures they coiranented that at 9 months at 70° F*
the product had a metallic flavor and at 3hP F. had a raw flavor.
There were an increasingly greater number of comments after 15 months
storage on the fact that the 70° F, product was more mushy than those
held at 3^° F.
lyplcal comments on tomatoes held at 3h0 F. were?
''goodj but raw flavor., good tomatoes*1! where held at 70° F. the comjnents were Metallic $ flat^ blands slightly dark^ burned flavor"*
The judges severely criticized the colorj flavor and acceptability
rating of tomatoes held at 110° F.
At 3 months storage they criticized
flavor more than color and commented that the tomatoes were "off*
color$ high metallic flavor and bad texture"*
refrained from tasting the tomatoes*
At 6 months the judges
Between 3 and 6 months the
product deteriorated so as to make it unacceptable.
were extremely mushy at this time.
The tomatoes
93
SUMMRY
The influence of storage temperatures of 34°* 70° and 110° F* on
retention of vitamins^ color5 U, S, grade and palatability in citrus and
tomato products was studied over a 24 months period.
With the exception of the grapefruit-orange juice blend all
products retained 92 percent or more of ascorbic acid in 34° F#
Storage*
The blend retained 88 percent after 24 months at 34° F,
After 24 months at 70° F. there was considerable reduction while at
110° F* the loss of ascosfoic acid was very rapid.
Storage at 70° F«
for 12 months gave a retention of 82 percent or more for all products.
Temperatures at or below 70° F* will give satisfactory retention of
ascorbic acid while a temperature of 110° F. will result in more or
less severe deterioration of the Vitamin*
After 24 months at 34° F* niacin retentions ranged from 83 to
92 percent for tomato and citrus productsv
the lower figure*
Grapefruit sections gave
At 70° F» for 24 months retention was 76 to 91 percent
with citrus sections again low*
Storage at 110° F» for 12 months
resulted in retention between 89 and 97 percent.
The favorable
retention of niacin at 110° F» is of no significance5 howevert since
the products were unmarketable«,
Refrigerated "storage for the reten-
tion of niacSii would not be necessary or economically profitable*
Thiamine retention was influenced by both temperature and duration of storage*
Storage for 24 months at 34° F. gave thiamine
99
retentions above 90 percent in all products except canned tomatoes*
Tomatoes retained 10 percent less thiandne than tomato juice at 3U0 F,
At 70° Ffs 8U to 92 percent thi&mine tsas retained and again tomatoes
vere 10 percent lower than tomato juice*
Citrus sections retained
more thiamine after %h. months than other citrus products.
The loss
of thiamine at 110° F. t-ras more rapid in citrus than in tomato pro*,
ducts.
About on© third of the thiaraine was gone after 3 months
storage of citrus products at the high temperature^ ttdle a loss of
more than 10 percent occurred with the tomato products»
The retention of riboflavin ms satisfactory in all products
after 2k months at 3ii0 F.
Citrus sections retained 88 percent while
the other products retained from 92 to 96 percent of the initial
content*
At 70° F,, the loss of riboflavin during 2h months storage
was lowest {11 percent) in canned tomatoes and highest (25 percent)
in citrus sections.
Storage at 110° F. for 12 months gave only 19
percent retention in citrus sections while the balance of the products
retained from 50 to 70 percent*
Little significance can be attached
to the rapid loss of riboflavin at 110° F. since the products were
unmarketable after 3 months at this temperature*
At 3U0 F, for 21* months the pantothenic acid retention ranged
between 71 and 79 percent*
Storage for 12 months at 3U0 F. gave
retentions of 85 to 96 percent*
Storage at 70° F*$ resulted in
decreased pantothenic acid content.
All products with the exception
of citrus blend contained approximately 76 percent after 12 months
100
while the blend retained 90 percent*, After 24 months the retention
fxas only 54 percent, or 20 percent less than at 34° F*
Storage at
HO0 F. resulted in a rapid loss of pantothenic acid.
The rate of
loss iras more rapid in the citrus sections than in the other citrus
products and slavsrer in the tomato products than in citrus products,,
especially during the first 3 months of storage. At least 85 percent
of pantothenic acid could bo retained in all products for a period of
12 months at 34° F»
The amber/green tristimulus filter ratio indicated little change
in products stored at 34° and 70° F.s for 24 months*
The individual
filter readings changed but there vtas no change in the ratio. This
vas in agreement vrith the assignment of points for color in U* S.
grade* At storage of 110° F. the ratio increased in all of the
citrus products^ as a result of increased broraning.
There was a
close correlation between browning as expressed by the ratio of the
amber/green tristimulus filter and retention of ascorbic acid.
The
correlation coefficients for the citrus products were as followst
Grapefruit juice
-0.852 - 0*086
n~ 10
Orange juice
-0.759 ± 0.122
ne 12
Grapefruit-orange blend
-0.936 ± 0.050
n^ 6
Grapefruit sections
-0.900 t 0.066
nc 8
All correlation coefficients •were significant at the 0.01 level.
Tomato juice gave a rapid increase in ratio during 6 months followed
by a rapid narrowing of the ratio and development of a brown color.
101
The ratio became more narrow In canned tomatoes as the time of storage
increased,.
The filter ratio combined x-rith ascorbic acid analyses
should be useful in determining age and probable storage conditions
of citrus products*
Such relationship does not hold as accurately
in tomato products*
From the standpoint of economics* the most important influence
of time and temperature of storage is the effect on U. S. grade and
consumer acceptance or "palatabilityM of the product.
The foregoing
data demonstrate conclusively that low temperature (3l;0 F.) storage
Ts&H preserve the grade and palatability level of the products studied.
liien citrus juices are stored at 70° F.,, the iaitial grade is retained
for 12 monthsj after which the flavor limits the product to the next
lowest grade.
Storage beyond 12 months results in loti-jer total scores
but not lower grades.
fifieen months.
Orange juice maintained the initial grade for
The grade of citrus sections was affected after 12
months due to color xshiie at 15 months character of fruit and drained
weight affected the grade.
These factors became lofcier as the period
of storage increased at 70° F*
Canned tomatoes were U. S. grade
C at 15 months on the basis of wholeness and drained weight.
These
two factors received lot-ier point scores as storage time Increased*
The loss in weight of grapefruit sections and whole tomatoes tias
accompanied by a loss in texture,
This x&s very noticeable and was
discriminated against by the judges.
It was v®rj difficult to
preserve the form of these two products when they were lifted from
a serving dish.
102
CONCLUSIONS
1*
Generally speaking, storage for 9 to 12 months at temperatures
between 34° and 70° F» will result in retention of at least 80 percent
of the vitamin content.
with storage at 34.° F*
Better retention of the vitamins vvss obtained
Storage at 110° F. resulted in the very rapid
loss of all the vitamins except niacin,
;2#
Refrigerated storage is important from th© standpoint of
retention of natural color in citrus and toniato products*
Storage
for a period of 24. months at 34° and 70° P.* resulted in practically
no change in the color*
Storage at 110° F*. for a period of 3 months
caused a severe deterioration in the color which became increasingly
pronounced as the time of storage was prolonged.
3«
The beneficial effects of 1cm temperature storage were
quite pronounced with respect to U. S. grade.
maintailed the initial grade for 24 months.
Storage at 34° F*
Storage at 70° F# was
satisfactory for a period of 9 months but thereafter there was a
loss in grade.
grade,
Storage at 110° F, resulted in a very rapid loss in
With citrus juices the loss was due to color and flavor.
With tomato juice the loss in grade at 3 months was due -bo flavor
and at 6 raonths to flavor and color.
In citrus sections and whole
tomatoes the loss in grade was due to such factors as colors flavorj,
drained weighty wholeness and character of fruit.
Continued high
103
temperature storage resulted in an unappealing and isushy product.
It may be concluded that if citrus and tomato products are held longer
than 9 months at 70° F* it would be necessary to shift to a lower temperature to prevent further reduction in grade*
loh
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