The effect of storage on the qualities and ascorbic acid content of Montana grown McIntosh apples
by Mary Baxter Briggs
A THESIS Submitted to the Graduate Committee in partial fulfillment of the requirements for the
degree of Master of Science in Home Economics at Montana State College
Montana State University
© Copyright by Mary Baxter Briggs (1945)
Abstract:
The average ascorbic acid content of the Montana-grown McIntosh apples used in this study was found
to be 2.08 milligrams per 100 grams of raw apple. There was a significant decrease in the ascorbic acid
values of the apples during four months of storage at a temperature ranging from 32 to 40 degrees F.
and a relative humidity ranging from 6o to 86 per cent. The greatest decrease in the ascorbic acid value
of the apples occurred during the first month of storage. This was followed by an increase in ascorbic
acid during the second and third months of storage which suggests the possibility of vitamin C
synthesis in the apple. A reduction in ascorbic acid value was again noted during the fourth month of
storage. Throughout the storage period, data were obtained on the rate of evaporation in the apples and
changes in their moisture content due to respiration, and with these data the percentage losses of
ascorbic acid were computed on a dry basis. Baring four months of storage the average percentage loss
of ascorbic acid in the apples was slightly over 30 per cent while, at the end of one month of storage,
the loss amounted to 37.5 per cent. Consistent results were obtained to show that the concentration of
ascorbic acid is more than 2 or 3 times greater in the outer area than in the inner area of the McIntosh
apple.
Although the individual apples differed somewhat in density and ascorbic acid value, there appeared to
be no correlation between the density and the ascorbic acid value of an apple. The total acidity of the
apples was found to decrease steadily throughout storage. However, the pH values showed a slight
tendency to fluctuate. The pectic acid content was reduced more than 50 per cent during three months
of storage.
The scores recorded by a panel of judges indicated that the most-noticeable changes occurring in the
apples during storage were decreased firmness and juiciness, accompanied by wrinkling of the skin.
In general, cookery of the apples results in large percentage losses of ascorbic acid. THE EFEBCT OF STORAGE OH THE qtJALITIES AHD ASCORBIC AOID COHTEHT
OF MOHTAEA-GEOWH McIHTOSH APPLES
, .
"by
MARY B.
BRIGGS
A THESIS
Subm itted to th e Graduate Committee
■i n
p a r t i a l f u l f i l l m e n t o f th e req uirem ents
f o r th e degree o f
M aster o f S c ie n c e i n Home Economics
at
Montana S ta te C o lle g e
Approved:
iairm an, Graduate C om m ittee'
Bozeman, Montana
May, Ig^S
c^t
^
TABLE OF CONTENTS
ABSTRACT ..................................................................................................................
Page
3
INTBDIfUCTION.........................................................................................................
5
HISTORICAL BACKGROUND
...................................................................................
S
EXPERIMENTAL PROCEDURE...................................................................................
S to rag e c o n d itio n s ...............................................................................
Loss o f w eight o f a p p le s d u rin g s t o r a g e ......................................
M o istu re c o n t e n t ...................................................................................
pH v a l u e .....................................................................................................
T o ta l a c i d i t y ....................................................
P e c tic a c i d ................................................................................................
S tarch
........................................................................................................
D e n s i t y ...............................................................................................................
A sco rb ic a c id d e t e r m i n a t i o n ..............................................................
A sc o rb ic a c id i n a re a s o f th e a p p l e ................................................
J u d g i n g ...............................................................................................
Cookery p r o c e s s e s ...................................................................................
I 1L
14
15
15
15
l£>
I?
I?
17
19
20
20
RESULTS....................................................................................................................
A sco rb ic a c id v a l u e s ...........................................................................
Changes i n a s c o rb ic a c id v a lu e s d u rin g s to ra g e ....................
P e rc e n ta g e lo s s e s o f a s c o rb ic a c id d u rin g s to ra g e . . . .
A sc o rb ic a c id i n a re a s o f th e ap p le ............................................
D e n sity .........................................................................................................
pH v a lu e .....................................................................................................
T o ta l a c i d i t y ............................................................................................
P e c t i c a c i d ................................................................................................
Ju d g in g
..........................
C o o k e r y .............................................................
23
23
23
29
DISCUSSION OF R ESU LTS...................................................................................
4O
SUMMARY....................................................................................................................
%3
CONCLUSIONS . .
44
ACKNOWLEDGMENTS
45
LITERATURE CITED AND CONSULTED .
46
75708
35
35
35
35
ABSTRACT
The a v erag e a s c o rb ic a c id c o n te n t o f th e Montana-grown M cIntosh a p p le s
u s e d in. t h i s stu d y was found to be 2 .0 8 m illig ra m s p e r 100 grams o f raw
a p p le .
There was a s i g n i f i c a n t d e c re a se i n th e a s c o rb ic a c id v a lu e s o f th e
a p p le s d u rin g f o u r months o f s to ra g e a t a te m p e ra tu re ra n g in g from 32 to 40
d e g re e s F. arid a r e l a t i v e h u m id ity ra n g in g from 6o to 86 p e r c e n t.
The
g r e a t e s t d e c re a se i n th e a s c o r b ic a c id v a lu e o f th e a p p le s o c c u rre d d u rin g th e
f i r s t month o f s to ra g e .
T h is was fo llo w e d by an in c re a s e i n a s c o rb ic a c id
d u rin g th e second and t h i r d months o f s to ra g e which su g g e s ts th e p o s s i b i l i t y
o f v ita m in C s y n th e s is i n th e a p p le .
A re d u c tio n i n a s c o rb ic a c id v a lu e was
a g a in n o te d d u rin g th e f o u r th month o f s to r a g e .
Throughout th e s to ra g e
p e r io d , d a ta were o b ta in e d on th e r a t e o f e v a p o ra tio n i n th e a p p le s and
changes i n t h e i r m o is tu re c o n te n t , due to r e s p i r a t i o n , and w ith th e s e d a ta th e
p e rc e n ta g e lo s s e s o f a s c o rb ic a c id were computed on a d ry b a s i s .
B arin g f o u r
months o f s to ra g e th e av erag e p e rc e n ta g e l o s s o f a s c o rb ic a c id i n th e a p p le s
was s l i g h t l y o v e r 30 p e r c e n t w h ile , a t th e end o f one month o f s to ra g e , th e
l o s s amounted to 37.5 p e r c e n t.
C o n sis te n t r e s u lts ,w e r e o b ta in e d to show
t h a t th e c o n c e n tra tio n o f a s c o rb ic a c id i s more th a n 2 o r 3 tim es g r e a t e r
i n th e o u te r a r e a th a n i n th e in n e r a re a o f th e M cIntosh a p p le .
A lthough th e in d iv id u a l a p p le s d i f f e r e d somewhat i n d e n s ity and
a s c o r b ic a c id v a lu e ,
t h e r e ' ap p eared to b e no c o r r e la tio n betw een th e
d e n s ity and th e a s c o rb ic a c id v a lu e o f an a p p le .
The t o t a l a c i d i t y o f
th e a p p le s was found to d e c re a se s t e a d i l y th ro u g h o u t s to r a g e .
th e p H -values showed a s l i g h t ten d en cy to f l u c t u a t e .
" However,
The p e c t i c a c id
c o n te n t was re d u c ed more th a n 50 p e r c e n t d u rin g th r e e months o f
s to r a g e .
The s c o re s re c o rd e d by a p a n e l o f ju d g e s in d ic a te d t h a t th e mostn o tic e a b le changes o c c u rrin g i n th e a p p le s d u rin g s to ra g e were d e crea se d
V
firm n e s s and j u i c i n e s s , acco n p an ied b y w rin k lin g o f th e s k in .
I n g e n e r a l, cookery o f th e a p p le s r e s u l t s i n la r g e p erce n ta g e
l o s s e s o f a s c o r b ic a c id .
THE EH1EHiCI OE STORAGE 017 THE QUALITIES AED ASCORBIC ACID CONTENT
r
OE M0ETAHA-GH01E McIHTOSH APPLES
' IITTRODUCTIOE '
E o r many y e a r s , th e a p p le h a s heen one o f th e most w id e ly -u sed
fru its .
S e v e ra l f a c t o r s have c o n tr ib u te d to i t s p o p u la r ity i n th e
A m erican d i e t .
I n th e f i r s t p la c e , th e a p p le can be p ro d u ced w ith r e l a ­
t i v e ease i n alm ost any p a r t o f th e c o u n try , and th e n , th e cro p c an be
s to r e d f o r lo n g p e r io d s o f tim e u n d e r fa v o ra b le c o n d itio n s .
As a r e s u l t ,
th e a p p le i s a r e l a t i v e l y in e x p e n siv e f r u i t t h a t can be p u rc h a se d a t a l l
sea so n s o f th e y e a r .
F u rth erm o re , th e n a tu r a l q u a l i t i e s o f th e ap p le
i t s e l f —a p le a s in g aroma and f l a v o r , a c r is p t e x tu r e , and a v e r s a t i l i t y
f o r cookery p u rp o s e s , have made i t a g e n e r a l f a v o r i t e .
Throughout th e U n ite d S t a t e s , th e r e a r e b e in g p ro d u ced many v a r i e t i e s
o f a p p le s , each e x h ib itin g c h a r a c t e r i s t i c q u a l i t i e s .
The p o p u la r ity o f a
v a r i e t y depends on th e d e s i r a b i l i t y o f th e s e q u a l i t i e s , and may change
d u rin g a. p e r io d o f y e a r s .
E or example, Gould (IS )* h a s r e c e n tly s ta t e d ,
t h a t i n 1928 th e r e were t e n le a d in g v a r i e t i e s o f a p p le s , each coming
w ith in tb e ra n g e .of 4 .1 to 8 .4 p e r c e n t o f th e t o t a l commercial p ro d u c tio n .
However, i n 1943 th e D e lic io u s ;a p p le l e d w ith l 6 p e r c en t o f th e t o t a l
p ro d u c tio n and th e M cIntosh came n e x t w ith 1 0 .5 p e r c e n t.
I n M ontana, e x te n s iv e p la n tin g o f a p p le t r e e s began ab o u t 1906»
Johnson, i n h i s stu d y o f th e M cIntosh a p p le in d u s tr y i n W estern Montana,
1929 (2 3 ), r e p o r te d t h a t n e a r ly a l l o f th e p la n tin g s a f t e r 1920 were o f th e
M cIntosh v a r i e t y .
He found t h a t most o f th e - h ig h g ra d e M cIntosh a p p le s
* numbers i n p a re n th e s e s r e f e r to l i t e r a t u r e c ite d .
- 6 were sh ip p ed to th e New York m arket and were s o ld a t a premium above
o th e r v a r i e t i e s o f w e ste rn a p p le s .
A 1935 f r u i t survey i n Montana (5)
re v e a le d th a t o f 3 5 5 , a ppl e t r e e s , 7 1 .8 5 p e r c e n t were o f th e McIn­
to s h v a r i e t y .
A lso i n a re c e n t comm unication from an a g r i c u l t u r a l
s t a t i s t i c i a n i n Montana (31) th e sta te m e n t i s made t h a t about 90 p e r cent
o f th e a p p le p ro d u c tio n i n th e commercial a p p le c o u n tie s o f Montana i s
o f th e M cIntosh v a r i e t y .
T h is s t e a d i l y grow ing p r e fe re n c e f o r th e
M cIntosh a p p le can d o u b tle s s be a t t r i b u t e d to th e d e s i r a b i l i t y o f i t s
q u a litie s .
I n a d d itio n to a n a t t r a c t i v e b r i g h t re d s k in c o lo r in g , i t
h a s a c r i s p , j u ic y , te n d e r te x t u r e , a t a r t a ro m a tic f l a v o r , and le n d s
i t s e l f to a wide v a r ie ty o f u s e s , w hether raw o r cooked.
W hile th e appearance and f la v o r o f a fo o d la r g e ly in f lu e n c e i t s
market v a lu e , i t i s e q u a lly im port ant to g iv e some c o n s id e r a tio n to i t s
n u t r i t i v e v a lu e .
S in c e the. p r o d u c tio n and u s e o f th e M cIntosh ap p le i n
Montana i s g r a d u a lly in c r e a s in g , th e consumers a r e j u s t i f i e d in .a s k in g
f o r some in fo rm a tio n about th e n u t r i e n t s c o n tr ib u te d b y t h i s p o p u la r
fr u it.
One o f th e more e s s e n t i a l n u t r ie n t s u s u a lly fou n d i n f r u i t s i s
v ita m in 0 o r a s c o r b ic a c id , so i t would seem eap e d ie n t to o b ta in some
in fo r m a tio n about th e co n ten t o f t h i s v ita m in i n th e Montana-grown
M cIntosh a p p le .
I n 193^» F e l l e r s i n M a ssa ch u setts (9) r a te d v a r i e t i e s
o f a p p le s i n th e d e c re a sin g o rd e r o f t h e i r v ita m in C c o n te n t and p la c e d
th e M cIntosh a p p le in group 4 a s a p o o r so u rce o f v ita m in C.
B e c e n tly ,
F is h and co-w orkers (13) d eterm in ed th e a s c o r b ic a c id c o n te n t o f s e v e ra l
v a r i e t i e s o f West V ir g in ia a p p le s and found th a t th e M cIntosh co n ta in ed
7 to 10 m illig r a m s p e r 100 grams o f t i s s u e , which would c l a s s i t among
*
.
-
th e p o o r e r s o u r c e s .
grown
1
-
I t m ight he ex p ecte d th a t th e M cIntosh a p p le a s
i n Montana would b e com parable i n a s c o r b ic a c id co n ten t to th e
M cIntosh a s grown i n o th e r p a r t s o f . th e U n ite d S t a t e s , b u t Maynand and
B eeson ( 36 ) h ave su g g e ste d th a t d if f e r e n c e s i n c lim a t ic c o n d itio n s may
make a s i g n i f i c a n t d if f e r e n c e i n v ita m in C v a lu e s .
Ih e y s t a t e th a t o f
c lim a t ic f a c t o r s , l i g h t seems to have th e p rep o n d era tin g in f lu e n c e on
th e accu m u lation o f a s c o r b ic a c id i n p la n t s .
I n a d d it io n , i t i s r e c o g n iz e d th a t c e r t a in methods o f trea tm en t, such
a s sto r a g e o r cook ery, a f f e c t th e n u tr itio n a l-v a lu e o f p la n t m a t e r ia ls .
Very
l i t t l e h as b een rep o rte d on th e e f f e c t s o f sto r a g e on th e a s c o r b ic a c id
. c o n te n t o f M cIntosh a p p le s , and y e t m ost o f th e a p p le s have b een s u b je c te d
to a p e r io d o f s to r a g e b e fo r e b e in g u se d .
Furtherm ore, no in fo rm a tio n
seems to be a v a ila b le on th e l o s s e s o f a s c o r b ic a c id i n M cIntosh a p p le s '
d u rin g cookery p r o c e s s e s and y e t many o f th e a p p le s a r e cooked b e fo r e b ein g
consumed.
I t i s t h e r e f o r e apparent th a t th e r e i s a need f o r s p e c i f i c in ­
fo rm a tio n con cern in g th e r e t e n t io n o f a s c o r b ic a c id i n th e M cIntosh a p p le s
produced i n Montana.
As 8 means o f se c u r in g such needed n u t r it io n a l in fo r m a tio n , t h i s
stu d y was p la n n ed t o d eterm ine th e q u a l i t i e s and a sc o r b ic a c id co n ten t
o f Montana-grown M cIntosh a p p le s , when p la c e d i n s to r a g e and a t m onthly
i n t e r v a l s d u rin g fo u r months o f s to r a g e , th e a p p les to be t e s t e d b oth
raw and cooked.
-S HISTOH CAL BACKGH3UND
I n t e r e s t was shown, i n th e n u t r i t i v e v a lu e o f a p p le s a s e a r ly a s
1916 w hen' Buhner (43) p r e s e n te d a n a l y t i c a l d a ta g iv in g th e com p o sitio n o f
a p p le s and o th e r w in te r f r u i t s and v e g e ta b le s .
However, a n in d ic a tio n o f
th e p re s e n c e o f v ita m in C i n a p p le s seems to have a p p ea re d f o r t h e . f i r s t
tim e i n th e r e p o r ts o f G ivens, McClugage, and Van Home i n 1921 and
1922 (1 5 ,1 6 ).
They found t h a t a p e r diem dose o f 10 grams o f raw ap p le
would p r o t e c t a g u in e a p i g a g a in s t scurvy f o r th r e e m onths, w h ile
p r o t e c t i o n was n o t sec u re d by an e q u iv a le n t amount o f a p p le cooked a t
100 d e g re es C f o r f i f t e e n m in u te s .
A few y e a r s l a t e r , Kohman, Eddy,
and C a rlss o n (29) conducted s im ila r s tu d ie s and found t h a t 15 grams o f
raw a p p le f e d ev ery o th e r day p ro v e d i n s u f f i c i e n t to p r o t e c t from sc u rv y .
Of th e a p p le s h e ld i n c o ld s to ra g e from -O ctober to M arch, ab o u t tw ice th e
fe e d in g dose was r e q u ir e d to p ro d u ce th e same e f f e c t a s w ith f r e s h a p p le s .
A n o th er e a r ly r e p o r t on th e v ita m in C c o n te n t o f a p p le s a p p ea re d i n 1929
i n which H e s s le r and C raig (21) s t a t e d t h a t when 20 grams o f raw Jo n ath a n .
a p p le s were fe d d a ily to g u in e a p i g s d u rin g th e p e rio d from Septem ber to
December, th e y d id n o t q u ite g iv e p r o t e c t i o n a g a in s t scu rv y ,
'from December
to F e b ru a ry , 30 to 40 grams o f raw a p p le were re q u ire d to a f f o r d th e same
d eg ree o f p r o t e c t i o n .
At about th e same tim e a group o f E n g lis h w orkers
(5 ) r e p o r te d th e v ita m in C c o n te n t o f E n g lis h v a r i e t i e s o f a p p le s .
They
found th a t th e v ita m in C i n th e p e e l o f th e a p p le was th r e e o r fo u r tim es
a s c o n c e n tra te d a s t h a t i n th e o u te r c o r te x and s ix tim e s a s co n cen trated ,
a s t h a t i n th e in n e r c o r te x .
G ivens, McClugage, and Van H om e ( l b ) ,
F e l l e r s ( l l j , Manvil i e , McMinis , and G huinard (3 4 ), T o d h u n ter (4 8 ),
B a tc h e ld e r and O v erh o lzer ( 4 ) , K o lesn ik ( 30 ) , Eheart ( S ) , Keys ( 2 6 ,2 7 ) ,
and Gross (l*9) a l l gave e v id e n c e to s u b s t a n t ia t e th e b e l i e f th a t th e
p e e l i s a much r ic h e r sou rce o f v ita m in O th an th e in n er p o r t io n o f th e
a p p le .
Z ilv a t Kidd, W est, and P er ry ( 5 4 ) , E n g lis h w orkers, went fu r th e r
t o s t a t e th a t i n a d d itio n to b e in g more co n cen tra ted n ea r th e s k in ,v ita m in
C was more c o n c e n tr a te d i n th e red p e e l o f Bram ley a p p le s than i n th e g ree n
p e e l,
A s im ila r c o n c lu s io n was made by K e s s le r ( 25 ) working w ith German
a p p le v a r i e t i e s , t h a t f r u i t which had r ip e n e d u n ev en ly b eca u se o f shading
had 30 to 50-P e r cen t more a s c o r b ic a c id on t h e red s id e .
t h i s in c r e a s e i n v ita m in C to l i g h t i n t e n s i t y .
He a t t r ib u t e d
Maynard and E eeson ( 36)
a ls o con clud ed th a t l i g h t a f f e c t e d v ita m in O c o n te n t, show ing, f o r in s t a n c e ,
th a t th e q u a n tity o f a s c o r b ic a c id in f r u i t grow ing on d if f e r e n t p a r ts o f
one t r e e may be p r o p o r tio n a l to th e amount o f l i g h t r e c e iv e d during r ip e n ­
in g .
Todhunter ( 36 ) con clud ed th a t f r u i t on th e o u ter exposed .branches
had c o n s is t e n t ly h ig h e r a s c o r b ic a c id co n ten t th an f r u i t from th e in n er
b ran ch es.
There h as been c o n s id e r a b le ev id e n c e, i n a d d itio n to t h a t shown
i n e a r ly work ( 2 1 , 2 $) to in d ic a t e th a t s to r a g e , a l s o , h as a marked
in f lu e n c e on th e a s c o r b ic a c id co n ten t o f a p p le s .
F e l l e r s , C lev ela n d ,
and C lague (10) rep o rted a 20 p e r c e n t l o s s o f a s c o r b ic a c id in fo u r to
s i x months o f s to r a g e w h ile B a tch eld e r ( 3 ) rep o rted a l o s s o f IJ per.
cen t a f t e r th r e e months s to r a g e and 25 p e r cen t l o s s a f t e r s i x months..
A
d e c r e a se o f 1 2 .4 to 5 2 .5 p e r cen t o f th e i n i t i a l v a lu e on s t o r a g e was shown
by K o le sn ik ( 30 ) .
S tu d ie s by Marsh ( 35 ) and by M a n v ille et a l (34) b oth
r e v e a le d r e d u c tio n o f v ita m in C co n ten t during sto r a g e o f a p p le s .
~ 10 —
F is h (12) fcnmd t h a t , i n g e n e r a l, th e r e was c o n s id e ra b le l o s s o f a s c o rb ic
a c id d a rin g th e f i r s t two months o f s to ra g e h it d u rin g th e second two
months th e r e was only a sm all a d d itio n a l l o s s .
He f u r t h e r in d ic a te d t h a t
a s c o rb ic a c id was l o s t from th e s k in more r a p id ly th a n from th e f l e s h
d u rin g s to ra g e .
O n-the o th e r hand, Keys (26) re p o rte d t h a t Uew Z ealand-
grown S tu r a e r a p p le s were r e l a t i v e l y r i c h i n v ita m in 0 and m a in ta in e d h ig h
v a lu e s a f t e r many months o f s to r a g e .
lo s s e s o f a s c o r b ic a c id a p p e a r to v a ry w ith s to ra g e te m p e ra tu re .
K e s s le r (25) n o te d th a t th e s to ra g e o f a p p le s a t a te m p e ra tu re below 5
d e g re e s 0 . f o r f i v e months r e s u l t e d i n v e ry l i t t l e l o s s o f v ita m in C.
B racew ell e t a l (5) s t a t e d t h a t th e v ita m in 0 c o n te n t o f Bramley
S e e d lin g a p p le s grown i n E ngland was unchanged a f t e r s to ra g e i n a i r
a t 3 d e g re es 0 . f o r f i v e m onths, bu t T odhunter (49) th o u g h t t h a t a sto ra g e
te m p e ra tu re above 32 d e g re es F. (0 d eg rees 0 .) d id not fa v o r v ita m in C
re te n tio n .
' .
E h e a rt (S) concluded t h a t lo s s e s o f v ita m in C were, g r e a tly
re d u c ed i f th e a p p le s were s to r e d below 4o d e g re es F . ( 4 .5 d e g re es 0 .) '
and B a tc h e ld e r (4) b e lie v e d th e r e was more l o s s a t 40 th a n a t 32 deg rees
E.
West and Z ilv a (52) have r e c e n tly r e p o r te d a d i f f e r e n t e f f e c t o f
s to r a g e , a ten d en cy tow ard a n o tic e a b le in c r e a s e i n th e t o t a l v ita m in 0
c o n te n t o f a p p le s., e s p e c ia ll y w ith e a r ly p ic k e d f r u i t , th u s su g g e stin g th e
p o s s i b i l i t y o f s y n th e s is o f v ita m in C i n s to r e d a p p le s .
I t was n o t s p e c if ie d
w hether th e compound s y n th e s iz e d was a s c o rb ic a c id o r d e h y d ro -a sc o rb ic a c id .
I n a d d itio n to th e p r e s e r v a tio n o f a s c o r b ic a c id c o n te n t, sto ra g e
c o n d itio n s may a ls o a f f e c t th e k eep in g q u a l i t y o f a p p le s .
F o r example,
.
H x v iere and P ic h a r d (42) concluded from a s to ra g e stu d y t h a t f r u i t s s to r e d
- 11 -
i n d a rk n e ss k ep t, lo n g e r th a n th o s e s to r e d i n l i g h t .
P o t t e r (39) and
Hassmussen ( 4 l) found t h a t s to ra g e a t 30 d e g re es F. le n g th e n e d th e k eep in g
l i f e o f th e M cIntosh v a r i e t y , a lth o u g h th e u ltim a te q u a lity was no t equal
to t h a t r e s u l t i n g from s to ra g e a t 32 d e g re e s F .
H e lle r , S t. Jo h n , and
Rowell (3 7 ), H a lle r (2 0 ), and K e rte sz (24) r e p o r te d changes i n th e q u a lity
and q u a n tity o f p e c t i c c o n s ti tu e n ts d u rin g s to ra g e .
H a lle r s t a t e d f u r t h e r
t h a t th e r a t e o f c o n v e rsio n a t d i f f e r e n t te m p e ra tu re s was p r o p o r tio n a l to
th e r a t e o f s o f te n in g o f a p p l e s 'i n s to ra g e .
B a tc h e ld e r (3 ) concluded t h a t
th e v a r i e t y o f a p p le and th e te m p e ra tu re and co m p o sitio n o f th e sto ra g e
atm osphere w ere a ls o im p o rta n t f a c t o r s .
f h e e f f e c t o f cookery on th e a s c o r b ic a c id co n ten t o f a p p le s has been
th e s u b je c t o f a number o f s t u d i e s , th e e a r l i e s t b ein g t h a t o f G ivens,
McOlugage, and Van H om e (1 5 ) , p r e v io u s ly c i t e d .
H e s s le r and W illiam s (22)
r e p o r te d t h a t sauce, made from a p p le s , o f w hich 20 grams o f th e uncooked
a p p le p r o te c te d g u in e a p ig s from sc u rv y , was' o f p r a c t i c a l l y no v a lu e .
T odhunter (4s) n o te d a 50 p e r c en t lo s s o f v ita m in G i n p r e p a r in g sauce
from Winesap a p p le s , w h ile O urran and co-w orkers ( 6 ) , making chem ical
a n a ly s e s f o r a s c o rb ic a c id , n o te d lo s s e s when a p p le s were b ak ed o r u sed
f o r sauce o r p i e .
Keys (26) was a ls o aw are t h a t o x id a tio n o f v ita m in 0
was r a p id when a p p le s were h e a te d .
The q u e s tio n o f .r e la tio n s h ip betw een f e r t i l i z e r i n th e s o i l and
th e i n i t i a l v ita m in G c o n te n t o f a p p le s h a s b een a c o n tr o v e r s ia l one.,
B a tc h e ld e r (2) r e p o r te d t h a t a p p le s from t r e e s re c e iv in g com plete
f e r t i l i z e r tre a tm e n t seemed r i c h e r i n v ita m in 0 . Maynard and Beeson (36)
th o u g h , p o in te d o u t t h a t i t was n o t s t a t e d i n th e stu d y by B a tc h e ld e r
- 12 w h e th er c o n s id e r a tio n was g iv e n to th e p o s i t i o n o f th e f r u i t on th e t r e e .
Hor was a n _ a c tu a l s o i l d e f ic ie n c y e s ta b lis h e d .
B racew ell an d co-w orkers (5)
and Io d h iin te r (50)have s t a t e d t h a t no e v id en c e was o b ta in e d to in d ic a te
a r e l a tio n s h ip betw een n itr o g e n and v ita m in C.
-
K e s s le r (2 5 ) , on th e
o th e r hand, b e lie v e d t h a t o v e r - f e r t i l i z i n g o f - t r e e s w ith n itr o g e n d e p re sse d
th e a s c o r b ic a c id c o n te n t o f th e f r u i t . .
R egarding q u a l i t y , Smock and
B oynton (46) p o in te d out t h a t a d isa d v a n ta g e o f in c r e a s in g amounts o f
n itr o g e n f e r t i l i z e r was an a p p a r e n t. d e c re a se i n firm n e ss o f f r u i t a t
h a r v e s t tim e .
However th e r a t e s o f s o fte n in g d u rin g s to ra g e were' no t
in c re a s e d .
N u tr it io n w orkers have c o n sid e re d many o th e r f a c t o r s a s h av in g a
p o s s i b l e in f lu e n c e on th e a s c o rb ic a c id c o n te n t o f a p p le s .
T odhunter (4g)
p r e s e n te d a summary o f th e s e s tu d ie s showing th a t seaso n , a g e o f t r e e ,
im m a tu rity o f f r u i t when p ic k e d b e fo re norm al h a r v e s tin g tim e , chromo­
some number o f th e a p p le s , t o t a l a c i d i t y , su g a r o r ash c o n te n t appeared
to have no r e l a t i o n to th e a s c o rb ic a c id c o n te n t o f a p p le s b u t con­
c lu d e d t h a t v a r i e t y seemed to be th e c h ie f f a c t o r a f f e c t i n g v ita m in C
c o n te n t.
W hether d a ta were o b ta in e d from b io lo g ic a l a ss a y o r from
chem ical a n a ly s e s o f a p p le s , th e r e a p p e a rs to be a wide ra n g e i n a s c o rb ic
a c id c o n te n t o f th e d i f f e r e n t v a r i e t i e s .
H e s s le r and C ra ig (21) s ta t e d
t h a t 20 grams o f raw J o n a th a n d id n o t q u ite g iv e p r o te c tio n from scurvy
to g u in e a p i g s , w hile M a n v ille, McMinis , and C huinard (34) re p o rte d th a t
10 grams o f G ra v e n ste in gave p r o t e c t i o n .
Dove and Murphy (7 ) have shown
t h a t th e V itam in C c o n te n t o f N o rth e rn Spy a p p le s i s f i v e to s i x tim es t h a t
o f th e M cIntosh v a r i e t y ,
f i s h , Dustman, and M arsh (13) have an aly zed
th e a s c o rb ic a c id v a lu e s o f s e v e ra l v a r i e t i e s o f a p p le s and have c l a s s i f i e d
them a c c o rd in g to v itam in ' C c o n te n t.
F o r e z a n p le , Duchess and Eed Duchess
c o n ta in 15 to 20 m illig ra m s o f a s c o rb ic a c id p e r 100 grams o f t i s s u e ;
G olden D e lic io u s , J o n a th a n , Stayman W inesap, and Grimes G olden, 10 to 15
m illig ra m s ; and M cIntosh, M aiden B lu sh , Wagener, W ealthy, York Im p e ria l,
M elba, ■and Borne B eauty, 7 to 10 m illig ra m s .
Maynard and Beeson (36) summarized th e q u e s tio n o f c a u s e s o f
v a r i a t i o n i n th e v ita m in C c o n te n t o f p l a n t s by n o tin g t h a t i t seemed
j u s t i f i a b l e to conclude t h a t th e accum ulation o f a s c o rb ic a c id i n p la n ts ,
i s a c h a r a c t e r i s t i c o f s p e c ie s and v a r i e t y and th a t t h i s g e n e tic in flu e n c e
may overwhelm any d if f e r e n c e s due to en v iro n m en tal c o n d itio n s .
-1 4 Ex p i EEMEH1TAL PEODEDUEE
Ih e M cIntosh a p p le s u s e d i n t h i s s tu d y were o b ta in e d th ro u g h th e
c o o p e ra tio n o f th e H o r tic u ltu r e departm ent from th e Moen O rchard a t
B ig fo rk , M ontana, and w ere e x tr a fan cy g ra d e w ith an av erag e c o lo r con­
s i s t e n t l y o v e r 66 p e r c en t and av erag e s iz e w ith .IjO to 150 a p p le s to a
box.
The a p p les', produced by young t r e e s a p p ro x im a te ly tw e lv e y e a rs o ld ,
were a l l p ic k e d e a r ly i n O ctober and p la c e d i n common s to r a g e a t about 4o
d e g re es E.
As soon as p o s s i b l e , s e v e ra l boxes o f unwrapped a p p le s were
tr a n s p o r te d to th e la b o r a to r y f o r t e s t m a te r ia l and were a t once p la c e d
i n a perm anent s to ra g e .
S to ra g e c o n d itio n s ?
P e rm is s io n w as se c u re d to s to r e th e a p p le s i n a
" w a lk -in r e f r i g e r a t o r " i n th e S tu d en t Union B u ild in g on th e campus, where
f r e s h fo o d s , in c lu d in g - f r u i t s , v e g e ta b le s and m eats, were s to r e d a t a l l
tim e s .
The r e f r i g e r a t o r , equipped w ith an a i r c o o lin g u n i t , m a in ta in e d a
te m p e ra tu re ra n g in g from 32 to 40 d eg rees E. ( O to 4 .5 d e g re es .0. ) a cc o rd ­
in g to re a d in g s ta k e n each week.
The r e l a t i v e h u m id ity was a ls o o bserved
w eekly and was found to range from 60 to SG p e r c e n t, a s d eterm in ed by a
T a y lo r h y g ro m eter.
The boxes o f a p p le s were p la c e d on s h e lv e s i n the
r e f r i g e r a t o r e a r ly i n Hovember and were s to r e d th e r e th ro u g h March.
At
m onthly i n t e r v a l s th e y were s o r te d and th e few b ru is e d o r s p o ile d a p p les
were d is c a rd e d .
L oss o f w eigh t o f a p p les d arin g s t o r a g e :
To ob serve th e l o s s o f w eight
by e v a p o ra tio n d u rin g s to r a g e , fo u r a p p le s were selected " a t random from
each o f th r e e boxes and p u t in to c h e e s e c lo th b a g s, which w ere b u rie d i n th e
c e n te r o f th e r e s p e c tiv e b o x e s.
The w eight o f each bag o f a p p le s was ta k e n
" a t th e b e g in n in g o f th e s to ra g e p e r io d and a t m onthly i n t e r v a l s t h e r e a f t e r ^
- 15 -
&W l o s s o f w eight was assum ed to he a n i n d i c a t i o n o f th e l o s s th a t o c c u rre d ■
i n th e a p p le s th ro u g h o u t th e box.
M o istu re c o n te n t;
The m o is tu re c o n te n t o f th e a p p le s was d eterm in ed a t
th e b e g in n in g o f th e perm anent s to ra g e p e r io d and a t m onthly i n t e r v a l s
t h e r e a f t e r so t h a t th e a s c o rb ic a c id v a lu e s .c o u ld b e computed on b o th
m o ist and d ry b a s e s .
F o r t h i s t e s t , a m o d if ic a tio n o f th e A.O.A.C.*
m ethod ( I ) was u s e d ,
A
r a d i a l s e c tio n o f a p p le , c o n s is tin g o f
b o th p e e l an d f l e s h , was p u lp e d w ith m o rta r and p e s t l e and sp re a d a s
ev en ly a s p o s s ib le o v er th e bottom o f a w eighed m etal d is h p ro v id e d w ith
a t i g h t l y f i t t e d c o v er.
The sample and d is h were weighed and d r ie d i n a
vacuum oven a t a p r e s s u r e o f a b o u t,25 mm. o f m ercury and a t 70 d eg rees C.
f o r e ig h t h o u rs .
A t th e end o f th e d ry in g p e r io d , th e ' d is h was covered,
p la c e d i n a d e s ic c a to r to co o l .and th e n w eighed.
p o s s i b l e to compute m o is tu re l o s s .
From th e s e d a ta i t was
T his t e s t was re p e a te d w ith samples
from f i v e d i f f e r e n t a p p le s a t each o f th e m onthly t e s t i n g p e r io d s .
pH v a lu e :
I t seemed d e s ir a b le to m easure p e r i o d i c a l l y th e pH v a lu e of*
sev e ra l, a p p le s to f i n d w hether a r e l a tio n s h ip e x is te d betw een t h i s f a c t o r
and th e a s c o r b ic a c id c o n te n t.
A 1 0 -gram r a d i a l s e c tio n o f a p p le , b o th
p e e l an d f l e s h , was dropped i n t o 100 m l. o f d i s t i l l e d w a te r and h ien d ed
f o r fo u r m in u te s i n a W aring B len d o r.
A f te r f i l t e r i n g th e m ix tu re , th e
pH v a lu e o f th e f i l t r a t e was d eterm in ed u s in g a g la s s e le c tr o d e and a
Cameron pH m e te r.
The pH v a lu e s f o r f i v e a p p le s were o b ta in e d a t each t e s t ­
in g p e r io d .
T o ta l a c i d i t y :
T o ta l a c i d i t y was a ls o d eterm in ed a t m onthly i n t e r v a l s to
* A s s o c ia tio n o f O f f i c i a l A g r ic u ltu r a l C hem ists
—i6 —
a s c e r t a i n changes o c c u rrin g i n th e a p p le s d u rin g s to ra g e and to n o te any,
r e la tio n s h ip betw een t o t a l a c i d i t y and a s c o r b ic a c id c o n te n t.
The s o lu tio n
u s e d i n d e te rm in in g t o t a l a c i d i t y was p re p a re d a c c o rd in g to th e A.O.A.C.
m ethod ( l ) by ad d in g a 75-gram sample o f raw a p p le to 200 m l. o f d is ­
t i l l e d w a te r and b le n d in g f o r fo u r m in u te s i n a Waring B len d o r.
The
s o lu tio n was b o ile d f o r one h o u r, d u rin g which tim e w a ter was added a t
i n t e r v a l s to- r e p la c e w a te r l o s t by e v a p o ra tio n , and th e n th e s o lu tio n
was t r a n s f e r r e d to a 500 m l. v o lu m e tric f l a s k , co o led , made up to volume,
and f i l t e r e d .
T o ta l a c i d i t y was d eterm in ed by t i t r a t i n g 25 m l. o f t h i s
s o lu tio n w ith 0 .1 H HaOH, u s in g p h e n o lp h th a le in i n d ic a to r .
A t each t e s t ­
in g p e rio d , t h i s d e te rm in a tio n was made on each o f f i v e a p p le s .
P e c tic a c id :
S in c e p e c t i c c o n s ti tu e n ts o f a p p le s have been re p o rte d as
changing d u rin g s to ra g e , t e s t s were made to . d eterm in e th e e x te n t o f th e
change d u rin g th r e e months o f s to r a g e .
The p e c t i c a c id c o n te n t was
d e term in e d u s in g th e A.O.A.C. m ethod ( l ) .
A s o lu tio n o f a p p le was
p re p a re d a s f o r t o t a l a c i d i t y d e te rm in a tio n and 200 m l. were t r a n s f e r r e d
to a b e a k e r to g e th e r w ith two lumps o f cube su g a r.
A d d itio n o f 200 m l.
o f 95 p e r c en t a lc o h o l caused, th e fo rm a tio n o f a p r e c i p i t a t e which was
f i l t e r e d o f f and washed w ith th e a lc o h o l.
The p r e c i p i t a t e was th e n
t r a n s f e r r e d to th e o r i g i n a l b e a k e r w ith h o t w a te r, e v a p o ra te d to ab o u t
40 m l. and c o o le d to 25 d e g re es 0 .
To t h i s were added 5 ml* o f a s o lu tio n
o f HaOH (10 p e r c e n t) and w a te r to make a t o t a l volume o f 50 m l.
s o lu tio n was a llo w ed to s ta n d 15 m in u tes b e fo re
m l. o f d i l u t e HQl were added.
The
m l, o f w a te r and 10
A f te r b o i l i n g f o r 5 m in u te s, a p r e c i p i t a t e
o f p e c t i c a c id was fo ra e d which was f i l t e r e d o f f and washed w ith h d t
-17 w a te r.
The p r e c i p i t a t e was washed h ad e i n t o th e o r ig i n a l b e a k e r, th e :
volume was a g a in a d ju s te d to
d e g re e s C.
m l. and th e s o lu tio n was c o o le d to 25
The s a p o n if ic a tio n w ith d i l u t e HaOH, p r e c i p i t a t i o n w ith d i l u t e
HCl, and h o ila n g were re p e a te d .
The p r e c i p i t a t e o f p e c t i c a c id was washed
th o ro u g h ly w ith h o t w a te r, t r a n s f e r r e d to a p o r c e la in c m c i h le and d rie d
i n an e l e c t r i c oven f o r 24 h o u rs a t 65 d e g re es C.
w eighed, i g n i t e d and weighed a g a i n .
The d r i e d sample was
The l o s s i n w eight re p re s e n te d th e
gmount o f p e c t i c a c id i n th e a p p le sam ple.
S ta r c h ;
A q u a l i t a t i v e t e s t f o r s ta r c h was made by dropping io d in e
s o lu tio n on a p p le s l i c e s .
A b lu e c o lo r a tio n wopld in d i c a t e th e p re se n c e
o f s ta r c h .
D e n sity :
I t seemed d e s ir a b le to m easure th e d e n s ity o f th e M cIntosh
a p p le s u s e d i n t h i s s tu d y so t h a t any p o s s ib le r e la tio n s h ip which m ight
e x i s t betw een t h e i r d e n s i t i e s and t h e i r a s c o rb ic a c id c o n te n t c o u ld b e
n o te d .
The d e n s ity o f th e a p p le s was d eterm in ed from a w eight-volum e
r e la tio n s h ip o b ta in e d by w eighing each o f te n a p p le s in a i r and a ls o
submerged i n W ater.
A sc o rb ic a c id d e te r m in a tio n ;
A naly ses were made to d eterm in e th e
a s c o rb ic a c id v a lu e s o f th e M ontana-grown M cIntosh a p p le s when p la c e d
i n s to ra g e and a t m onthly i n t e r v a l s th ro u g h o u t s to ra g e .
The L o e f f le r
and P o n tin g m ethod (32) f o r d e term in in g a s c o r b ic a c id was u se d on each
o f th e t e n a p p le s whose d e n s i t i e s h ad been p re v io u s ly d e term in e d .
The
method, i s b a se d on th e p r i n c i p l e t h a t u n d er -s u ita b le ex p erim en tal con­
d i t i o n s , a s c o r b ic a c id seems to q u a n t i t a t i v e l y reduce c e r t a i n c o lo re d r e - .
a g e n ts (2 8 ).
I n t h i s c a s e , th e b lu e dye, 2, 6 -d ich lo ro b e n z en o n e in d o p h e n o l,
— 18 —
was th e c o lo r e d compound and th e c o l o r . changes were record ed dn th e
galvan om eter o f an E velyn p h o t o e le c t r ic c o lo r im e te r .
a . . S ta n d a rd iz a tio n o f th e dye
The in s tru m e n t was a d ju s te d to re a d llIOOn w ith d i s t i l l e d w a te r i n
th e c o lo rim e te r tu b e .
Then th e dye s o lu tio n was made b y a d d in g approx­
im a te ly 13 mg. o f 2 , 6 - d i c h lo ro b enzenoneindophenol to I l i t e r o f ^ ! s t i l l e d
w a te r.
W ith a r a p id d e liv e r y p i p e t t e 9 m l. o f dye s o lu tio n were added
to I m l. o f m etap h o sp h o ric a c id s o lu tio n . ( I p e r c en t) i n a d ry , p o lis h e d
c o lo rim e te r tu b e .
The tu b e was shalosn s l i g h t l y , p la c e d i n th e c o lo rim e te r
and a g alv an o m eter re a d in g was ta k e n t e n seconds a f t e r th e s t a r t o f th e
dye a d d itio n .
T h is re a d in g was c a l l e d
and from t h i s was d e riv e d a
0
v a lu e c a l l e d Ir|_ u s in g th e c a l i b r a t i o n c h a r t. The L v a lu e which i s g iv e n
i n th e c a l i b r a t i o n ta b le i s o b ta in e d from th e eq u atio n s
L - (2 - lo g G-). ■
The av erag e o f L i v a lu e s f o r th r e e a c id sam ples was u s e d i n c a lc u la tio n .
The L i v a lu e was e s ta b lis h e d each day o r each tim e i t was n e c e s sa ry to
change a c id o r dye s o lu tio n d u rin g th e day.
b . Sam pling and b le n d in g
1
For th e a s c o r b ic a c id t e s t a 50-gram sample was ta k e n from a co red ,
u n p e e le d a p p le by c u ttin g opposing r a d i a l s e c tio n s no t ex ceed in g i inch
i n w idth a t th e s k in edge.
The sample was im m ediately dropped in to 350 m l.
o f m etaphos p h o ric a c id s o lu tio n ( I p e r c e n t) and b le n d e d i n a Waring
B len d o r f o r 4 m in u te s .
The r e s u l t i n g m ix tu re was f i l t e r e d th ro u g h
c o a rs e f i l t e r p a p e r .
c . T e s tin g f o r a s c o r b ic a c id
I n to each o f th r e e c le a n , d ry c o lo rim e te r tu b e s Was p i p e t t e d a
*
■ ■
=
I -m l. p o r ti o n o f th e f i l t r a t e . To th e f i r s t tu b e were added 9 nil. o f
d i s t i l l e d w a ter and w ith t h i s tube in s e r t e d i n the c o lo r im e te r , th e
galvan om eter'w as a d ju ste d to read "100", u s in g F i l t e r 520 and a 10 c c .
a p e r tu r e .
I o th e second tu b e were added 9 m l. o f dye s o lu t io n from a
r a p id d e liv e r y p i p e t t e .
The tu b e was s l i g h t l y a g it a t e d and a read in g tak en
10 secon d s a f t e r th e s t a r t o f th e dye a d d it io n .
The p roced u re f o r th e
secon d tu b e was rep ea te d on th e t h ir d tu b e and th e average o f th e two
rea d in g s was c a l l e d G-g from w hich a corresp on d in g v a lu e c a l l e d L2 was
o b ta in e d from th e c a lib r a t io n t a b le accompanying the E v ely n p h o t o e le c t r ic
c o lo r im e te r .
d. C a lc u la tio n
The amount o f a s c o r b ic a c id i n th e sam ple s o lu t io n was' c a lc u la t e d by
u s e o f th e fo llo w in g eq u a tio n :
mg. o f a s c o r b ic a c id p e r 100 grams o f a p p le
I K (L^-Lg) x m l.(g in .) a c id e x tr a c ta n t
( n e t . l i q u i d i n sample)
gm. sample
(gm .sam ple)
The v a lu e f o r th e K f a c t o r i s e s t a b lis h e d f o r each c o lo r im e te r and in 19%
was found to be 1 0 .8 f o r th e in stru m en t i n t h i s la b o r a to r y .
A sc o rb ic a c id i n a r e a s o f th e a p p le :
I n d eterm in in g th e a s c o r b ic a c id
co n ten t o f v a r io u s a rea s o f an a p p le, s l i g h t m o d ific a tio n s o f th e method
p r e v io u s ly d e s c r ib e d were u s e d .
A 25-gram sam ple o f th e o u te r a rea was
ta k en by rem oving p e e l and f l e s h to a depth n ot ex ceed in g i in c h .
The sample
was b len d ed w ith 175 m l. o f m etaphosp h e r ic a c id s o lu t io n ( l p e r cen t) and
filte r e d .
The a s c o r b ic a c id d eterm in a tio n Was made i n accord an ce w ith th e
above method. . A 25-gram sample o f th e in n e r f l e s h a r e a (rem ain in g a f t e r th e
p e e l and o u te r -g in c h o f f l e s h were removed) was a ls o b len d ed w ith 175 m l.
o f met apho sp h e r ic a c id s o lu t io n (l. p e r c e n t) and th e a s c o r b ic a c id co n ten t
.determ ined.
In c a s e s where t h e a s c o r b ic a c id co n ten t o f th e p e e l a lo n e was.
I
- 20 - •
determ ined, 25 grams o f p e e l were removed from th e a p p les hy th e u s e o f a
p a r in g b la d e on an a p p le c o r e r and th e sam ple was b len d ed w ith 1J5 m l. o f
m etaphosphoric a c id s o lu t io n ( I p e r c e n t) and t e s t e d f o r a s c o r b ic a c id .
Ju d gin g;
At each t e s t p e r io d , a p a n e l o f f i v e ju dges sc o r e d f i v e a p p le s ,
s e l e c t e d a t random from th e b o x e s .
Ehey u s e d a sco rec a rd e s p e c ia l ly p r e ­
p a red b y th e in v e s t ig a t o r , which p r o v id e d .f o r ju d g in g q u a l i t i e s o f appear­
a n ce, f la v o r , t e x t u r e and j u i c i n e s s .
(S e e page 21 f o r copy o f s c o r e c a r d ).
I t seemed o f i n t e r e s t to know how th e q u a l i t i e s o f th e Montanargrown
M cIntosh a p p le would r a te during s t o r a g e ..
Cookery p r o c e s s e s ;
.A pples were s u b je c te d to th r e e d if f e r e n t methods o f
cookery so th a t th e e f f e c t o f cookery on a s c o r b ic a c id co n ten t co u ld b e
n o te d .
a. Baked a p p les
•
'
U npeeled, co red a p p le s , each with" 6 grams o f sugar added, were
"cooked i n co v ered g la s s b a k in g d is h e s f o r 25 to 30 m in u tes a t 350 d egrees
F.
W eights were taken b e fo r e and a ft;er co o k in g .
Samples w eigh in g 50
grams were removed from th e c o o le d a p p le s by u s in g a c o r e f to cu t through
th e sk in from one s id e o f th e a p p le to th e o p p o s ite s id e .
The sam ples were
t e s t e d f o r a s c o r b ic a c id by th e method p r e v io u s ly d e s c r ib e d and p erce n ta g e
l o s s e s due to cookery were d eterm ined.
b . A pple p ie
P i e c r u s t was p rep ared a cco rd in g to stand ard method and was p r e s s e d
in t o a p y rex p ie pan.
A pp roxim ately 650 grams o f 3 /8 in c h s l i c e s from
co re d , p e e le d a p p le s were combined w ith su g a r, cinnamon, f lo u r and s a lt
o f known w e ig h t,
t
A top c r u s t was p r e s s e d in t o p la c e and th e p i e was baked
'
»
F o ss ib l e
sc o re ,Q u a lity _______
6
C o lo ro f s k in
dark re d
5
4
a/
6
ro sy re d w ith
dark gt re a k s
4
re d m th yellow
3
s p o ts
2
l i g h t re d
I
g re e n
Shaoe
5
u n ifo rm ly curved
5
4
f l a t t e n e d sid es
3
2
rough d ip s o r
b u lg e s
I
m isshapen
C o n d itio n o f sk in
5
smooth
5
4
s lig h tly
3
w rin k led
2
i
w rinkled
S co recard f o r Ju d g in g A pples
P o sApple Ho. s ib le
Apple Ho.
sco re ,Q u a l i t y _______ ^l £ I 4
I 2 3] 4
Freedomfrom decay
5
and in ju r y
unblem ished
5
4
b ru is e d
3
2
open b r u is e s
I
decayed
Firm ness
5
h a rd
3
4
firm
5
4
2
mealy
mushy
I
J u ic in e s s
5
v e ry ju ic y
3
4
ju ic y
5
2
s l i g h t l y dry
I
dry
P o ss ib le
Apple Ho.
sco re _ Q u a l i t y _____ I l 12 i4 12
C o lo r o f o u lo
5
w hite
5
4
creamy
3
2
I
brown
T e x tu re o f n u ln
5
c lo s e ,e v e n g r a in
5
4
m o d e ra tely d o s e
3
g r a in
2
I
c o a rse g ra in
b
F la v o r
2
so u r
6
m o d e ra tely sweet
aid aro m atic
5
4
sweet aid modera t e ly arom atic
b
la n d
3
I
b itte r
l
47 _ T o ta l Score
I n s t r u c t i o n s to ju d g e s: For each c h a r a c t e r i s t i c , check th e one word o r s e t o f words which b e st
d e s c rib e th e a p p le b e in g judged.
.
a / S cores w ith no accompanying d e s c r ip tio n p ro v id e d means f o r making in te rm e d ia te judgm ents.
- 22 a t 425 d eg rees P. f o r 50 m in u tes.
b a k in g .
W eights were tak en b e fo r e and a f t e r
When c o o l, a 50-gram sample was removed in a w edge-shaped s l i c e
ex ten d in g from th e o u te r edge to th e c e n te r o f the p i e .
A sco rb ic a c id
d eterm in a tio n was made a cco rd in g to th e p r e v io u s ly d e s c r ib e d method and
p e r c e n ta g e l o s s e s due to co o k in g were computed.
c . A pp le sau ce
A pple sau ce was p rep ared by th r e e d if f e r e n t methods and a sc o r b ic acidd eterm in a tio n s were made on 50 -gram sam ples from each l o t by th e method
p r e v io u s ly d e s c r ib e d .
•
!'he m ethods o f p rep a rin g a p p le sau ce were:
1 . P e e l and c o r e .225 grams o f a p p le .
'
Out i n e ig h th s and add
d i r e c t l y to 50 grams o f b o ilin g w ater.
i n a covered u t e n s i l .
Oook f o r 7 m inutes
Put a p p le s through a P o le y fo o d m ill
and add 20 grams o f su gar.
2. Core but do not p e e l 225 grams o f a p p le and p ro cee d a s in
method I .
3. P e e l and c o r e 225 grams o f a p p le .
Cut i n e ig h th s and add
d i r e c t l y to 50 grams o f b o ilin g .w ater.
Cook f o r 7 m inutes
i n a co v ered u t e n s i l and th e n add 20 grams o f su gar,
o m ittin g th e u s e tif a fo o d m i l l .
A sc o rb ic a c id a n a ly s e s were made to d eterm ine not o n ly p e r c e n ta g e lo s s e s
due to cook ery, but a ls o to ju d ge which method o f p r e p a r a tio n r e s u lt e d in
th e h ig h e s t r e t e n t io n o f a s c o r b ic a c id .
_ 23
,
EBSULIS
I n p r e s e n tin g the r e s u l t s o f t h i s s tu d y i t w ill h e n o te d i n ta b le I ,
t h a t th e a v erag e a s c o rb ic a c id c o n te n t o f th e Montana-grown M cIntosh
a p p le when p la c e d i n sto ra g e -w a s 2.08 m illig ra m s p e r 100 grams o f raw
a p p le .
A com parison o f t h i s v a lu e w ith th o s e o f o th e r commonly-used f r u i t s
i n d i c a t e s t h a t t h i s a p p le i s a p p a r e n tly a r a t h e r p o o r so u rce o f a s c o rb ic .
a c id .
F o r exam ple, th e approxim ate a s c o rb ic a c id c o n te n t o f 100 grams o f
s tr a w b e r r ie s i s about 65 m illig ra m s ; o f a b anana about 10 m illig ra m s ; o f
o n e - h a lf o f a m edium -sized g r a p e f r u i t , ab o u t
m illig ra m s ; and o f a sm all .
o ran g e, about 60 m illig ra m s .
I t may a ls o be seen i n t a b l e I t h a t th e average a s c o r b ic a c id v a lu e s
o f th e a p p le s u s e d i n t h i s stu d y a p p a r e n tly d e c lin e d d u rin g s to ra g e .
Ih e
m ost pronounced d e c re a s e i n a s c o rb ic a c id seemed to ta k e p la c e i n th e f i r s t
month o f s to r a g e , a f t e r which th e v a lu e s ap p eared to in c r e a s e f o r a tim e ,
o n ly to d im in is h a g a in d u rin g th e f o u r th month o f s to r a g e .
I t is of in te re s t
to n o te t h a t th e a v erag e a s c o rb ic a c id v a lu e a t th e end o f f o u r months o f
s to ra g e was a p p a r e n tly n o t a s low a s th a t a t th e end o f one month o f s to r a g e .
As a means o f d e te rm in in g th e s ig n if ic a n c e o f th e s e a p p a re n t changes i n
a s c o rb ic a c id v a lu e s shown i n t a b l e I , th e d a ta were s u b je c te d to s t a t i s t i c a l
tr e a tm e n t, u s in g a n a ly s is o f v a ria n c e fo llo w in g th e method o u tlin e d by
Snedecor (4 7 ) .
I h i s a n a ly s is ta k e s in to c o n s id e ra tio n t h e v a r i a t i o n in
a s c o rb ic a c id v a lu e o f th e in d iv id u a l a p p le s u s e d i n each m onthly t e s t and
th e d if f e r e n c e s i n th e a v e ra g e a s c o rb ic a c id v a lu e s d eterm in ed from month
to month d u rin g s to ra g e .
By means o f t h i s m ethod, i t i s p o s s ib le to
d e term in e w hether th e v a r i a t i o n betw een months i s more s i g n i f i can t th a n th e
- 24 -
TatiLe I .
Ascorbic acid values of raw EcIntosh .apples determined at
monthly in tervals during storage.
Ascorbic acid values of McIntosh armies
A pple
Ho.
I
When p la c e d
in
s to ra g e
m g./lOOgm.
2 .3 7 a /
S to re d
one
month
m g./lOOgm.
S to re d
two
months
m g./lOOgm.
S to re d
th r e e
months
mg. /lOOgm.
S to red
fo u r
months
mg./lOOgm.
l? 3 3
1 .2 7
I .3 6
1 .6 9
1.69
2
. 2.80
1 ,9 2
1.02
2.20
3
2.37
1 .3 3
1 .7 0
1 .3 6
' 4
2 .0 3
1 .3 3
2 .6 3
1 .7 0
1 .3 5 '
5
1 .6 9
1 .5 5
1 .9 5
1 .7 0
1 .3 5
6
1 .9 5
1 .3 3
1 .6 9
1 .9 5
1 .6 l
7
1 .9 5
l.ll
1.-95
2.20
1.6 9
S
2 .0 3
1 .8 5
1 .9 5
1.8 7
■ 1.9 5
S
1 .7 s
0 .5 2
I .6 9
1 .3 6
1 .4 4
10
1 .7 8
1 .0 3
1 .9 5
2.20
1 .3 5
Av.
2.08
1 .3 3
.1 .7 8
1 .7 9
1.5 5
S .d .
0 .3 4 3
0 .4 0 3 •
0 .4 3 4
0.351
O.209
a/
,
■
,
1 .3 5
In analyzing data a l l values were transformed to angular degrees
following the recommendation of Fisher and Yates (14).
‘
•
*■ 25 —
v a r i a t i o n w ith in th e m onths.
F i r s t , th e in d iv id u a l and group d a ta f o r a l l
th e m onthly t e s t i n g p e r io d s were used, and th e a n a ly s is i s shown i n t a b l e I I
where th e r a t i o between th e two mean sq u a re s in d ic a te s t h a t th e m onthly
group a v e ra g e s d i f f e r s i g n i f i c a n t l y among th e m selv e s.
S ince i n t a b l e I th e r e were a p p a re n t v a r i a t i o n s i n th e av erag e
a s c o rb ic a c id v a lu e s d e term in e d m onthly d u rin g s to ra g e , th e lo w est b ein g
re c o rd e d a t th e end o f th e f i r s t and f o u r months o f s to ra g e , i t seemed
d e s ir a b le to compare f u r t h e r each m onthly group o f a s c o rb ic a c i d v a lu e s
w ith th o s e o b ta in e d a t th e f i r s t t e s t i n g p e r io d .
From t a b l e s I I I
and VI i t i s e v id e n t t h a t th e v a ria n c e o f th e a s c o rb ic a c id v a lu e s
when p la c e d i n s to ra g e and t h e i r v a lu e s a f t e r one and f o u r months o f
s to ra g e i s h ig h ly s i g n i f i c a n t .
L ess s ig n if ic a n c e i s shown i n th e -v a ria n c e
between th e a s c o r b ic a c id v a lu e s o f th e a p p le s when p la c e d i n s to ra g e and
t h e i r v a lu e s a f t e r two o r t h r e e months o f s to r a g e ( t a b l e s IV and V);
- 26 T ab le I I .
A n a ly s is o f v a ria n c e o f a s c o rb ic a c i d v a lu e s o f M cIntosh
a p p le s d eterm in ed a t m onthly i n t e r v a l s d u rin g s to ra g e .
Source o f v a r i a t i o n
Between months
D egrees o f
freedom
Sum o f
sq u ares
M ean.
sq u are
4
1 0 .6 7
2.6 7 a /
W ithin months
45.
30.49
0 .6 7 8 •
T o ta l
49
4 l.l6
-
a / S ig n i f ic a n t v a r i a t i o n a t a 5% le v e l
Table I I I .
A n a ly s is o f v a ria n c e o f a s c o r b ic a c id v a lu e s o f M cIntosh
a p p le s d e teim in ed when p la c e d i n s to ra g e and a f t e r one month
o f s to ra g e .
Source o f v a r i a t i o n
D egrees o f
freedom
Sum o f
sq u a re s
Between months
I
1 4 .0 3
W ith in months
18
1 4,80
T o ta l
19
28.83
a / H ighly s ig n if ic a n t, v a r i a t i o n
Mean
sq u are
1 4 .0 3 a /
0 .8 2
•
- 27 !Table IV.
A n a ly s is o f v a ria n c e o f a s c o rb ic a c id v a lu e s o f M cIntosh a p p le s
d eterm in ed when p la c e d i n s to ra g e and a f t e r two months o f s to r a g e .
Source o f v a r i a t i o n
D egrees o f
freedom
Sum o f
sq u ares
Between months
I
W ithin months
is;
12.31
• I9
1 7.4b
T o ta l
a/
5 .1 5 .
5.1 5 a /
'
O.bS
S ig n if ic a n t v a r i a t i o n a t a 5$ le v e l
T a b le V.
A n a ly s is o f v a ria n c e o f a s c o rb ic a c id v a lu e s o f M cIntosh a p p le s
d e term in e d when p la c e d i n s to ra g e and a f t e r th r e e months o f
s to r a g e .
Source o f
v a ria tio n
D egrees o f
freedom
Between months
W ith in months
..
S ig n if ic a n t
v a ria tio n
Sum o f
sq u ares
Mean .
square
6.69
6; 69 a /
18
9 .1 4
0.51
19
1 5 .8 3
I .
T o ta l
a/
Mean
square
-
t
- 28 T ab le VI.
A n a ly s is o f v a ria n c e o f a s c o rb ic a c id v a lu e s o f M cIntosh a p p le s
d e term in e d when p la c e d i n s to ra g e and a f t e r f o u r months of
s to r a g e .
Source o f v a r i a t i o n
D egrees o f
freedom
Sum o f
sq u ares
Between months
I
11.59
W ith in months
IS
6.12
19
17.71
T o ta l
'
a / H ig h ly s i g n i f i c a n t v a r i a t i o n
Mean
sq u are
'
11.59 a /
0 .3 4
I n a d d itio n to re c o rd in g th e a s c o rb ic a c id v a lu e s o f th e a p p le s a s
d e term in e d a t monthly, i n t e r v a l s d u rin g s to r a g e , th e v a lu e s were compared to
d e term in e th e p e rc e n ta g e lo s s e s o f a s c o rb ic a c id from m onth t o month.
B efo re
making such a com parison i t was n e c e s s a ry to p u t th e v a lu e s on a co m p arativ e
b a s is .
One f a c t o r which a f f e c t e d th e v a lu e s o f th e s to r e d a p p le s was t h e i r
c h a n g e .in W eight due to lo s s o f m o is tu re by e v a p o ra tio n .
An in d ic a tio n o f
th e s e m o is tu re lo s s e s was o b ta in e d from th e w eight l o s s o f th e bags o f
■
a p p le s which h a d been b u r ie d i n th e b oxes o f a p p le s a t th e b e g in n in g o f th e
s to ra g e p e r io d .
By u s e o f th e s e d a ta i t was p o s s ib le to c o r r e c t th e
a s c o rb ic a c id v a lu e s f o r e v a p o ra tio n an d th u s to have com parable v a lu e s , a l l
b a se d on th e i n i t i a l g ro s s w eight o f th e b ag s o f a p p le s , from which to
d eterm in e p e rc e n ta g e lo s s e s o f a s c o r b ic a c id d u rin g s to r a g e .
These lo s s e s '-
may b e n o te d i n ta b l e VII w here th e g r e a t e s t p e rc e n ta g e d e c re a se o f
a s c o r b ic a c id seems to have o c c u rre d d u rin g th e f i r s t month o f s to ra g e w h ile
th e r e a p p ea rs to have been an in c r e a s e o f ^ s e o r b ic a c id d u rin g th e second and
t h i r d m onths.
I t may be o b serv ed , a ls o , t h a t th e p e rc e n ta g e lo s s o f a s c o rb ic
a c id a f t e r f o u r months was s l i g h t l y more th a n 30 p e r c e n t, which i s l e s s
th a n th e p e rc e n ta g e l o s s a t th e end o f th e f i r s t month.
P e rc e n ta g e lo s s e s computed on th e b a s i s o f d ry m a tte r a r e p re s e n te d
i n t a b l e V III.
I t may b e n o te d t h a t th e a v e ra g e p e rc e n ta g e o f d ry m a tte r
a p p ea re d to d e c re a se d u rin g th e t h i r d month o f s to ra g e even though evap­
o r a tio n d u rin g t h i s month was re p o rte d , i n th e p re v io u s t a b l e .
Such a
d e c re a s e i n d ry m a tte r may have been due to r e s p ir a to r y p ro c e s s e s o c c u rrin g
i n th e a p p le s d u rin g s to ra g e , i n which c a rb o h y d ra te s a r e c o n v e rte d to w a te r
and carbon d io x id e . (1 7 ).
-JPTaM e V II.
v
A verage p e r c e n ta g e l o s s e s o f a s c o r b ic a c id i n Montana-grown
M cIntosh a p p le s determ ined a t m onthly i n t e r v a l s du rin g fo u r
months o f s to r a g e and c o r r e c te d f o r m o istu re l o s s e s due to
ev a p o r a tio n .
9
P e rc e n ta g e Av. a s c o rb ic a c id c o n ten t A v e rag e p e rc en to f m o is tu re
c o rre c te d age l o s s .of
Storage1
l o s t by
o f raw
fo r •
a s c o rb ic
p e r io d
ev ap o ratio n
a p p le
evapora­
a c id
tio n
P e t.
m g./100 gm.
m g./100 gm,.
p e t. .
When p la c e d i n s to ra g e
2 . OS
2.08
S to re d one month
2 .5
1 .3 3
1,30
37-5.
S to re d two months
3-3 •
1 .7 7
1 .7 2
1 7 .3
S to re d th r e e months
4 .5
1 .7 9
1.71
S to re d fo u r months
6 .2
1 .5 5
. 1 .4 5
Avi
4.1
1 .7 0
' 1 .6 5
T ab le V I I I .
.
1 7 .s
3 0 .3
A verage p e r c e n ta g e l o s s e s o f a s c o r b ic a c id i n Montana-grown
M cIntosh a p p le s determ ined a t m onthly i n t e r v a l s during fo u r
m onths o f s to ra g e and c a lc u la te d on a d ry b a s i s .
S to ra g e
p e r io d
Average
p e rc e n ta g e
o f dry
m a tte r
A v .a sc o rb ic a c id c o n te n t
C a lc u la te d
o f raw
on a d ry
' a p p le
b a s is
m g./100 gm. mg./100 gm.
2.08
1 3 .4 7 .
A v e rag e p e rc en tage lo s s o f
a sc o rb ic
a c id
When p la c e d i n s to ra g e
p e t.
1 5 .4
S to re d one month
1 5 ,4
1 .3 3
8.42
37.5
S to re d two months
1 5 .8
1.78
10.89
1 9 .2
. S to re d th r e e months
1 5 .3
1 .7 9
11.15
1 7 .2
S to re d fo u r months
16.1
1.5 5 '
9.01
33.1
Av.
1 5 .6
1 .7 0
10.59
.
p e t.
•
'
- 31 -
:
An i n t e r e s t i n g f a c t i s r e p o r te d i n t a b l e IX where i t i s shown th a t
th e c o n c e n tra tio n o f a s c o rb ic a c id was g r e a t e r i n th e .o u te r a r e a o f th e
a p p le th a n i n th e in n e r a r e a .
T his g e n e r a l r e l a t i o n p e r s i s t e d th ro u g h o u t
s t o r a g e . . The r a t i o o f th e v a lu e s o f th e o u te r and in n e r a r e a s g ra d u a lly
d e c lin e d d u rin g th e f i r s t two months o f s to r a g e , in d ic a tin g t h a t th e
lo s s e s o f a s c o r b ic a c id were g r e a t e r from th e o u te r - a r e a th a n from th e
in n e r .
D uring th e t h i r d m onth, however, th e r e seems to have been a r a t h e r
in e x p la in a b le in c r e a s e i n th e a s c o rb ic a c id v a lu e o f th e o u te r a re a .
I n c o n sid e rin g th e a s c o rb ic a c id v a lu e s .o f th e a p p le s , t h e q u e s tio n
a r i s e s w hether c e r t a i n q u a l i t i e s such a s d e n s ity , pH, and t o t a l a c i d i t y
m ight a f f e c t th e s e v a lu e s .
S in c e a s c o rb ic a c i d i s r e a d ily o x id iz e d , i t
seems p o s s ib le th a t compact o r lo o s e s tr u c t u r e i n th e a p p le m ight in ­
flu e n c e th e amount o f oxygen h e ld w ith in i t s t i s s u e s .
An in d ic a tio n o f
s t r u c t u r e can b e o b ta in e d by m easu rin g th e d e n s it ie s o f th e a p p le s and
com paring them w ith t h e i r a s c o r b ic a c id v a lu e s .
i n t a b l e X.
These d a ta a r e p re s e n te d
I t w ill be n o te d th a t th e in d iv id u a l a p p le s v a ir e d o n ly
s l i g h t l y i n d e n s it y .
Some com putations o f c o r r e l a t i o n betw een th e
d e n s i t i e s and th e c o rre sp o n d in g a s c o r b ic a c i d v a lu e s were made u s in g th e
fo rm u la recommended by S nedecor (4 7 ).
The r e s u l t s o f th e com putations
re v e a le d t h a t no s i g n i f i c a n t r e l a t i o n seemed to e x i s t betw een th e
d e n s i t i e s and th e a s c o rb ic a c i d v a lu e s o f t h e a p p le s .
I n t a b le XI a r e shown th e pH v a lu e s o f th e a p p les determ ined a t
m onthly i n t e r v a l s during fo u r months o f s t o r a g e .
I n g e n e r a l, th e pH
v a lu e s in c r e a s e d a s s to r a g e p r o g r e s s e d , in d ic a t i n g th a t th e d eg ree o f
a c i d i t y was d e c r e a s in g .
I t i s i n t e r e s t i n g to n o te th a t d u rin g th e t h ir d
T ab le IX.
The a s c o r b ic a c id v a lu e s o f th e in n e r and o u te r a rea s o f
Montana-grown M cIntosh a p p le s determ ined a t m onthly in t e r v a ls
d u rin g th r e e months o f s to r a g e .
A pple No.
and
a re a
When p la c e d
in
sto ra g e
A sc o rb ic a c id v a lu e s
S to re d
S to red
one
two .
month
months
I - In n e r
m g./100 gm.
'0 .5 1
mg./100 gm.
1.2 7
m g./100 gm.
1.19
S to red
th re e
' months
mg./100 gm.
0.59
O u ter
2.29
2 .4 6
1 .8 6
1.9 5
2 - In n e r
1 .0 2
0 .9 3
0 .9 3
0 .8 4
O uter
3.30
2 .1 2
2 .12
1 .9 4
3- In n e r
0 .2 5
0.34
0 .6 8
0.85
O u ter
2.03
1 .8 6
1 .4 4
1.95
4 - In n e r
O.76
1.2 7
0.68
1 .1 0
O u te r
2.29
. 2.71
1.61
2.79
5 - In n e r
1 .2 7
0.93
0.68
0.7 6
O u ter
3.73
2 .4 6
1 .8 6
3,13
Av. f o r In n e r
0 .7 6
0.95
0 .8 3
0.83
Av. f o r O u te r
2.73
2 .3 2
1 .7 8
2.35
E a tio
3.59
2 .1 4
2.83
•S ' •
T ab le X.
The d e n s i t i e s and a s c o r b ic a c id v a lu e s o f raw Montana-grown M cIntosh a p p les determ ined
a t m onthly i n t e r v a l s during fo u r months o f s to r a g e .
App i e When p la c e d
Wo. i n s to ra g e
Den­
A scorbic
s ity
a c id
Sn. /m l. Hg. /100 gn.
I
.805
2.37
D e n s itie s and a s c o rb ic a c id v a lu e s o f M cIntosh a p p le s
S to re d one
month
Den­
A sc o rb ic
s ity
a c id
gn. /m l. mg. /100 gn.
.792
1 ,3 3
S to re d two
S to re d th r e e
S to re d fo u r
months
months
months
Den­
Den­
A sco rb ic
A sco rb ic DenA sco rb ic
s ity
s ity
acid .
a c id
• s ity
a c id
g n ./m l. Hg. /100 gn. gm ./m l. ng./lO O gn. g a ./m l. Hg./100 gm.
1.27
. .804
1 .3 6
.111
1 .6 9
.799
a
.793
2.80
.765
1 .9 2
.801
1 .0 2
.805
2.20
.797
1.69
3
.785
2.37
.770
1 .3 3
.796
.1 .7 0
.791
1 .3 6
.760 .
1 .3 5
4
.7bS
2 .0 3
,825
1 .3 3
.791
2 .6 3
.779
1 .7 0
.782
1-35
5
.80S
1.69
.7 8 4
1 .5 5
.787
1 .9 5
.781
1 .7 0
.775 ■
1.3 5
6
.788
1 .9 5
.813
1 .3 3
.765
1 .6 9
.7 8 4
1.9 5
.808
1.61
7
.778
1 .9 5
.815
1.11
.768
1 .9 5
.789
2 .20
.803
1 .6 9
S . .799
2 .0 3
.761
1 .8 5
.796
1.9 5
.793
1.87
.810
1 .9 5
9
.759
1 .7 8
.794
0 .5 2 :
.784
1 .6 9
.789
1 .3 6
.796
1 .4 4
10
.780
1 .7 8
.795
1 .0 3
.779
1 .9 5
.7 9 3
2.20
.787
1,35
Av.' .786
' 2.08
.791
1 .3 3
.787
1 .7 s
.791
1 .7 9
.790
1.5 5
•
i
V l
.
,
'
I
_ 34 -
S a b le X I.
A pple
Ho.
The pH v a lu e s o f raw M ontana-grown M cIntosh a p p le s d eterm in ed
a t m onthly i n t e r v a l s d u rin g fo u r months o f s to r a g e .
When p la c e d
in
s to ra g e
F pH -values o f raw M cIntosh a n c le s
S to re d
S to re d
' S to red •
S to re d
one
two
th re e
fo u r
month
months
months
months
I
3 .7 4
3. so
4.30
3 .9 3
3.9 5
2
3.75
3 .8 3
4.31
4.01
3 /#
3
3»6S
3. s i .
3 .9 2
3.83
3.9 0
4
3 .6 8
3.85
4.18
3. s i
4 .50
5
3.67
3 .8 2
3 .9 6
4 .1 2
4 .2 6
Av.
3.70
3 .8 2
4 .1 3
3 .9 4
4.10
.
m onth o f s to ra g e th e r e was. an in d i c a t i o n o f a s l i g h t in c r e a s e i n a c i d i t y .
Prom an exam in atio n o f t a b l e X II, i t i s e v id e n t t h a t th e t o t a l a c i d i t y
o f th e a p p le s u se d in t h i s stu d y a ls o d e c lin e d d u rin g s to r a g e .
I n com­
p a r is o n , th e a c i d i t y o f th e a p p le s a t th e b eg in n in g o f s to ra g e was n e a r ly
th r e e tim es, a s g r e a t a s a t th e end o f f o u r months o f s to ra g e .
A c o n s titu e n t o f a p p le s t h a t h a s i n t e r e s t e d w orkers f o r some tim e i s
th e group o f p e c t i c su b sta n c e s t h a t seem to undergo changes d u rin g rip e n ­
in g and s to r a g e .
I n o rd e r to o b serv e any such changes i n th e M cIntosh
a p p le s , th e p e c t i c a c id c o n te n t was d eterm in ed a t th e b e g in n in g and end
o f th r e e months o f s to ra g e and th e r e s u l t s a r e re p o rte d i n t a b l e X III.
A lthough th e firm n e ss o f th e a p p le s d id no t change v ery much d u rin g th r e e
months of. s to ra g e ( t a b l e XIV), th e p e c t i c a c id c o n te n t was red u ced more
th a n 50 p e r c e n t.
A summary o f th e s c o re s g iv e n to th e q u a l i t i e s o f th e a p p le s ' judged
a t m onthly i n t e r v a l s d u r iig f o u r months o f s to ra g e a p p ea rs i n t a b l e XIV.
A d e f i n i t e r e d u c tio n i n firm n e s s and j u i c i n e s s , w ith a d e c id e d w rin k lin g
o f th e s k in , was e v id e n t a f t e r fo u r months o f s to ra g e .
I t may b e seen,
t n a t i n th e o p in io n o f th e ju d g e s , th e a p p le s d e c re a se d somewhat i n
t o t a l q u a lity a f t e r one month o f s to ra g e and seemed to m a in ta in th a t
q u a lity d u rin g th e second and t h i r d months o f s to ra g e .
The most d ecid ed
d e c lin e i n t o t a l q u a lity , th ough, d id n o t o c c u r u n t i l d u rin g th e f o u r th
month o f s to r a g e .
The a s c o rb ic a c id c o n te n t o f a p p le s .c o o k e d by v a rio u s methods i s
shown i n t a b l e XV.
th e cooked p r o d u c t.
The d a ta a re e x p re sse d i n m illig ra m s p e r 100 grams o f •
I t may b e seen t h a t i n g e n e r a l, a p p le sau ce made by
- 36 -
A pple
No.
p-
A verage m l. o f N NaOH r e q u ire d to n e u tr a liz e
in 100 sms. o f a p p le
When p la c e d S to re d
S to re d
S to re d
in
one •
. two
th r e e
s to ra g e
month
months
months
I
The t o t a l t i t r a t a b le a c i d i t y o f Montana-grown M cIntosh a p p le s '
a s m easured a t m onthly i n t e r v a l s d u rin g fo u r months o f s to ra g e
and e x p re sse d a s m i l l i l i t e r s o f norm al sodium h y d ro x id e s o lu tio n .
! &
®
.0?able X II.
• S to re d
fo u r
months
I
7-93
6 .9 6
4.05
4.29
3.20
2
9 .3 8
5 .6 3
5 .8 1 .
5 ,3 3
3 .1 6
3
9 .1 5
5 .5 5
4 .6 6
4.0 3
4 .2 4
4
8 .3 8
6 .6 6
4 .i 6
5 .3 6
3 .7 3
11.00
5 .9 9
5 .2 5
3.97
3 .6 3
9.27
6 .1 4
4.7 9
4.6o
3 .5 4
5
Av.
•
.
'
- 37 -
T ab le X III.
A pple
Ho.
The p e c t io a c id co n ten t o f Montana-grown M cIntosh a p p les
d eterm ined a t th e "beginning and end o f th r e e months o f
s to r a g e .
P e rc e n t o f p e c t i c a c id
i n a o p le s
When p la c e d
S to red
in
th r e e
S to rag e
months-
I
0 .443
2
0 .4 3 4
0 .1 2 4
3
0 .440
.0 .3 1 2
Av.
0.439
0.197
’ '
Average
P e rc e n ta g e
. lo s s
0.156
55.13
- 38 T ab le XIV.
.
A verage s c o re s f o r q u a l i t i e s o f M cIntosh a p p le s ju dged m onthly
d u rin g fo u r months o f s to ra g e by a p a n e l o f f i v e ju d g e s.
(S ee s c o re c a rd , page 21 ) .
' Average s c o re s
Q u a lity
When p la c e d
in
s to ra g e
S to re d
one
month
S to red
two
months
S to re d
th r e e
' months
S to re d
fo u r
months
4 .8 4
4.36
3.40
3.60
C o lo r o f s k in
4.16
.4.08
4 .3 5
Shegp e
■4.16
3.5 6
4.00
C o n d itio n o f Skin
5.oo
5.00
5.00
3.9 2
3.00
Freedom from decay
and in ju r y
4.36
4.00
3.8 5
' 4.36
3 .9 2
F irm ness
4.84
3.84
4.25
4.08
3 .6 0 .
J u ic i n e s s
4 .6 4
4.64
4.25
4.28
3 .6 8
C o lo r o f p u lp '
4.32
. 4.56
4 .30
4.20
3.92
T e x tu re o f P u lp
4.04
4.04
4.20
3.68
4.52
F la v o r
4.76
4.88
• 4.05
4.32
4.16
40.28
3 8 .bO
38.25
37-08
34.76
A verage
a/
t o t a l sc o re .
a/
P e r f e c t t o t a l sco re 47
•
- 39 -
! a b l e X7.
A sc o rb ic a c id c o n te n t o f M ontana-grown M cIntosh a p p le s
cooked by d i f f e r e n t m ethods, w ith t e s t s re p e a te d a t m onthly
i n t e r v a l s .d a r i n g th r e e months o f s to ra g e .
A sc o rb ic a c id c o n te n t o f cooked M cIntosh a-onles
When p la c e d
S to re d
S to re d
S to red
in
one
two
th re e
s to ra g e
month
months
months
M ethod o f
cookery
S auce- Method I
m g./100 gm.
0 .2 5
mg.,/100 .gm.
0 .3 4
mg. /100 gm.
0.1 7
.
m g./100 gm,
0 .2 5
S auce- Method 2
0 .S 4
O.67 ■
0 .5 0
0 .2 5
Sauce- Method 3
1 .0 1
0.5 1
0 .4 2
0.5 0
Baked
0 .3 5
0 .3 4
0 .4 2
0 .2 5 ■
Baked i n p i e
0 .2 5
0 .3 4
0 .2 5
0.2 5
T ab le XVT.
P e r c e n ta g e l o s s e s o f a s c o r b ic a c id co n ten t o f Montana-grown
M cIntosh a p p le s ca u sed by cook ery and determ ined a t m onthly
i n t e r v a l s du rin g th r e e months' o f s to r a g e .
Method o f
co okery
S auce- Method I
P e rc e n ta g e lo s s e s o f a s c o rb ic a c id from cooked atroles
When p la c e d
S to re d
S to re d
S to red
in
one
two
th re e
month
s to ra g e
months
months
- p e t.
p e t.
■ p e t.
p e t.
88 .9
85.9
7 0 .3
•
83.7
S auce- Method 2
5 2 .6
4 2 .5
66.7
83.0
S auce- Method 3
4 4 .2
54 .5
72 .„&
6b.. 4
Baked
8 2 .g
7 3.0
75.9
85.7
Baked i n p ie
8 4 .2
67.1
8 5 .7
81.6
•
I
- W -
'
m ethod B, where th e .p eel was l e f t on. th e a p p le s , and method 3» where th e
p e e le d , cooked a p p le s were n o t s ie v e d , s u p p lie d more a s c o rb ic a c id th a n
a p p le s p re p a re d by th e th r e e o th e r m ethods.
As th e a p p le s were cooked
a t m onthly i n t e r v a l s d u rin g s to ra g e and t e s t e d , t h e i r a s c o r b ic a c id c o n te n t
showed a s l i g h t ten d en cy to d e c re a se d u rin g s to ra g e a lth o u g h in e z p la in a b le
f l u c t u a t i o n s i n v a lu e s seem to have o c c u rre d .
S im ila r i r r e g u l a r i t i e s
a p p e a r in t a b le XVI where th e p e rc e n ta g e lo s s e s o f a s c o rb ic a c id due to
co okery a r e re c o rd e d .
DISCUSSION OF HBSULTS
From th e fo re g o in g r e s u l t s i t i s e v id e n t t h a t th e a s c o rb ic a c id v a lu e
o f M ontana-grown M cIntosh a p p le s o f good q u a lity i s 2 .OS m illig ra m s p e r
100 grams o f t i s s u e , which means t h a t th e M cIntosh i s a r a t h e r p o o r so u rce
o f th is n u tr itiv e fa c to r.
A ccording to th e l i t e r a t u r e , o n ly a few w orkers
have r e p o rte d a s c o rb ic a c id v a lu e s f o r M cIntosh a p p le s and r e s u l t s o b ta in e d
i n M ontana a g re e c lo s e ly w ith th o se r e p o rte d i n 1934 by Sm ith and F e l l e r s (45)
i n M a s sa c h u se tts.
% means o f b io lo g ic a l a s s a y th e y found t h a t i t re q u ire d
from 20 to 25 grams o f th e M cIntosh a p p le d a ily f o r a p r o t e c t i v e dose f o r
g u in e a p i g s .
On th e b a s is t h a t 0 .5 m illig ra m s o f a s c o rb ic a c id a r e re ­
q u ire d d a ily to p r o te c t g u in e a p ig s from scu rv y t h i s would mean t h a t t h e i r
M cIntosh a p p le c o n ta in e d from 2 .0 to 2 .5 m illig ra m s o f a s c o rb ic a c id p e r 100
grams o f t i s s u e .
However, i n a re c e n t stu d y on a p p le s grown i n West V ir g in ia ,
F is h and co-w orkers (13) r e p o r t th e M cIntosh a p p le a s c o n ta in in g from 7 to
10 m illig ra m s o f a s c o rb ic a c id p e r 100 grams o f t i s s u e and y e t t h e i r method
d i f f e r e d somewhat from t h a t commonly u s e d .
T h is stu d y o f th e e f f e c t o f s to ra g e on th e a s c o rb ic a c id v a lu e s o f
-.41a p p le s a p p a r e n tly d i f f e r s from any o th e r s tu d ie s re p o rte d , in t h a t i t h a s
fo llo w e d from month to month th e changes i n a s c o rb ic a c id v a lu e s a s w ell
a s th e r a t e o f e v a p o ra tio n o f th e a p p le s and changes i n m o is tu re co n ten t
due to r e s p i r a t i o n .
F is h (1 2 ), B a tc h e ld e r ( 3 ) , and F e l l e r s and cp -
w orkers (10) have r e p o r te d p e rc e n ta g e lo s s e s o f a s c o rb ic a c id i n from
th r e e to s ix months and from e ig h t to te n months o f s to ra g e w ith no
in d ic a tio n t h a t th e y c o n sid e re d e v a p o ra tio n o r any changes i n m o istu re
c o n te n t.
I t i s o f s p e c ia l i n t e r e s t to n o te t h a t th e s to r e d a p p le s showed
th e lo w e st a s c o rb ic a c id v a lu e s a t th e end o f th e f i r s t month o f s to ra g e ,
w ith an in c r e a s e i n th e second a n d .t h i r d months and a d ro p p in g o f f o f
v a lu e d u rin g th e f o u r th month.
,
She o n ly o th e r w orkers who h av e n o te d
a n y th in g o f s im ila r n a tu r e a re West and Z ilv a (52) i n E ngland, who
r e c e n tly r e p o r te d t h a t v ita m in C was s y n th e s iz e d when a p p le s were s to re d
a t 3 d e g re es G. and th e c a p a c ity f o r s y n th e s is was h ig h i n young b u t a l ­
m ost n o n - e x is te n t i n m ature f r u i t .
There were no in d ic a tio n s o f im­
m a tu r ity i n th e Montana f r u i t and y e t th e r e were s i g n i f i c a n t s ig n s o f '
in c r e a s e s i n v ita m in G v a lu e s , o r p o s s ib le s y n th e s is , d u rin g th e second
and t h i r d month's o f s to ra g e a t 0 to 4 .5 d e g re es C.
The f in d in g th a t th e a s c o rb ic a c id v a lu e o f th e o u te r a r e a o f th e
M cIntosh a p p le i s more th a n two o r th r e e tim e s as- g re a t a s th e v alu e o f th e
in n e r a re a a g re e s v e ry w ell w ith s i m i l a r r e p o r ts by Keys ( 2 6 ) , Gross (1 9 ),
Io d h u n te r (4 8 ) , E h e a rt (£) and o th e r w orkers who re p o rte d g r e a t e r con- .
c e n t r a t io n o f a s c o rb ic a c id i n th e o u te r a r e a o f th e s p p le th a n i n th e
i n n e r a re a .
- 42 O th e r q u a l i t i e s o f th e a p p le s t h a t seem to have been a f f e c t e d by
s to ra g e a re t o t a l a c i d i t y and pH v a lu e o r d eg ree o f a c i d i t y .
U nlike
a s c o r b ic a c id v a lu e s , t o t a l a c i d i t y v a lu e s showed a ste a d y d e c lin e th ro u g h ­
out th e e n t i r e s to ra g e p e r io d .
However th e pH v a lu e s showed some o f th e
same te n d e n c y to f l u c t u a t e th a t th e a s c o rb ic a c id v a lu e s showed d u rin g
s to r a g e .
The t o t a l a c i d i t y d e c re a se d c o n s id e ra b ly d u r in g 's to r a g e , b u t i n
c o n t r a s t , even though th e re .W e re a ls o changes i n th e pH v a lu e s , th e r e was
s t i l l a f a i r l y h ig h degree o f a c i d i t y a t th e end o f th e f o u r months o f
s to r a g e .
Thus i t seems p o s s ib le th a t pH m ight have th e g r e a t e r in flu e n c e
on a s c o rb ic a c id r e te n tio n .
I n g e n e r a l, a p p le s undergo g r e a t lo s s e s of. a s c o rb ic a c id d u rin g
coo k in g .
G urran and T r e s s le r ( 6 ) , i n an e x te n s iv e stu d y o f th e e f f e c t s
o f cookery on a s c o rb ic v a lu e s o f a p p le s , r e p o r te d ^ p r o x im a te lo s s e s o f
80 p e r c e n t due to baking a p p le s , whole o r i n p i e .
Though cooked
a p p le s have a p p e t i t e s p p e a l and a re i n common u s e , th e y have l i t t l e
re c o g n iz e d n u t r i t i v e v a lu e , b e in g e s p e c ia ll y low i n v ita m in 6 c o n te n t.
I
- 43 •SUMMARY
I n t h i s stu d y i t was found th a t th e average a s c o r b ic a c id co n ten t o£th e Montana-grown M cIntosh a p p le a s p r e v io u s ly d e s c r ib e d , i s 2 ,0 8 m illig r a m s
p e r 100 grams o f raw a p p le .
When th e a p p le s were p la c e d i n sto r a g e f o r fo u r
months at a tem perature ra n g in g from
32 to . 4o
d eg rees F , and a r e l a t iv e
h u m id ity ran gin g from 60 to SG p e r c e n t, th e r e was a s i g n i f i c a n t d ecrea se
i n th e a s c o r b ic a c id v a lu e s .
The g r e a t e s t d ecrea se i n th e asco rb ic, a c id
v a lu e o f th e a p p le s o ccu rred during th e f i r s t month o f s to r a g e .
T h is was
fo llo w e d by an in c r e a s e i n a s c o r b ic a c id v a lu e during th e second and t h ir d
months o f s to r a g e which s u g g e s ts th e p o s s i b i l i t y o f v ita m in 0 s y n th e s is i n
th e a p p le .
A r e d u c tio n i n a s c o r b ic a c id v a lu e was § g a in n o te d during th e
fo u r th month o f s to r a g e .
Throughout th e s to r a g e p e r io d , d a ta
were o b ta in e d
on th e r a te o f ev a p o ra tio n i n th e a p p le s and changes i n t h e i r m o istu re con­
t e n t due to r e s p ir a t io n .
With th e s e d a ta a v a ila b le , th e p e r c e n ta g e l o s s e s
o f a s c o r b ic a c id were computed on a dry b a s i s .
During fo u r months o f s to r a g e ,
th e average p e r c e n ta g e l o s s o f a s c o r b ic a c id i n th e a p p le s was s l i g h t l y over
30 p e r cent w h ile , at th e end o f one month o f s to r a g e , th e l o s s amounted to
3 7 .5 p e r c e n t .
C o n siste n t r e s u l t s were o b ta in e d to show th a t th e con cen tra­
t io n o f a s c o r b ic a c id i s c o n s id e r a b ly g r e a t e r i n th e o u te r a rea than i n th e
in n e r a rea o f th e M cIntosh a p p le .
A lthough th e in d iv id u a l a p p les d if f e r e d somewhat i n d e n s it y and a s ­
c o r b ic a c id v a lu e , th e r e appeared to b e no c o r r e la t io n b etw een th e d e n s it y
and th e a s c o r b ic a c id v a lu e o f an a p p le .
The t o t a l a c i d i t y o f th e a p p le s
Was found to d e c r e a se s t e a d i l y throughout s to r a g e .
However, th e pH v a lu e s ,
o r th e d egree o f a c i d i t y , showed a s l i g h t ten d en cy to f l u c t u a t e . . The
>
—
p e c t i c a c id c o n te n t was red u ced more th a n 50 p e r c e n t d u rin g th r e e months
o f s to r a g e .
The s c o re s re c o rd e d Tby a p a n e l o f ju d g e s in d ic a te d t h a t th e most
n o tic e a b le changes o c c u rrin g i n th e a p p le s d u rin g s to ra g e were d e crea se d '
firm n e ss and j u i c i n e s s , accom panied by w rin k lin g of th e s k in .
-
I n g e n e r a l, cookery o f th e a p p le s r e s u l t s i n la r g e p e rc e n ta g e lo s s e s
o f a s c o rb ic a c id .
CQHCLUSIOUS
The a v erag e a s c o rb ic a c id c o n te n t o f th e Montana-grown M cIntosh
a p p le s u sed i n t h i s stu d y i s 2 .OS m illig ra m s p e r 100 grams o f raw a p p le .
The s to ra g e o f M cIntosh a p p le s f o r f o u r months a t a te m p e ra tu re
ra n g in g from 32 to W d e g re es P* and a r e l a t i v e hum idity, ra n g in g from 6o
to 86 p e r c e n t r e s u l t s i n a s i g n i f i c a n t r e d u c tio n i n a s c o rb ic a c id
v a lu e am ounting to about 30 p e r c e n t, computed on a d ry b a s i s .
D uring t h i s same s to ra g e p e r io d and u n d er th e same c o n d itio n s o f
s to r a g e , th e M cIntosh ap p le s u s ta in e d some changes i n q u a lity , in d ic a te d
by a w rin k lin g o f th e s k in and a d e c re a se i n firm n e s s .
ACHOiftEBGMEBJTS
The au th or w ish es to ex p ress h er s in c e r e a p p r e c ia tio n to D octor
J e s s i e E. R ich ard son , o f th e Department o f Home Economics o f th e Montana
A g r ic u ltu r a l Experim ent S t a t io n , f o r th e s u g g e s tio n s and g u id a n ce g iv e n
d u rin g t h i s stu d y and to th e H o r tic u ltu r e Department f o r th e a p p les u se d
i n t h i s stu d y .
— 46 —
LIIIHtATUHE CITED MD CONSULTED
1.
A s s o c ia tio n o f O f f i c i a l A g iic u l t u r a l C hem ists
1925. O f f i c i a l and T e n ta tiv e M ethods o f A n a ly s is . A s s o c ia tio n o f
O f f i c i a l A g r ic u ltu r a l C hem ists, W ashington, D. C.
2.
B a tc h e ld e r , E. I .
1932. The V itam in C ontent o f th e W ashington-C rom E m i t s . W ash.S tate
H o rt. A ssoc. ,P r o c .28th Annual M eeting, p . 177. C.A. 2 8 :4 7 7 1 .(1 9 3 4 )
3.
193^»
.
.
'
.
’
■
V itam in C i n D e lic io u s A pples B efo re and A f te r S to ra g e .
J . K u t r i t i on
4.
________ ^_______ _ , and O v e rh o ls e r, E. L.
1936° F a c to rs A ffe c tin g th e V itam in C C ontent o f A p p les.
J . A gr. R esearch 53: 547.
5.
B ra c e w e ll, M. F . , K idd, F ., W est, C ., and Z ilv a , S .S .
1931» The A n tis c o r b u tic P o ten cy o f A p p le s. Biochem, J , 25:138.
6.
C urran, K. M ., T r e s s le r , D. KX, and K ing, C. C.
1937♦ L o sses o f V itam in C D uring Cooking o f H o rth e m Spy.A pples.
Food H esearch 2:549*
7.
Dove, W. F . , and Muiphy, E .'
.
.
.
1936. The V itam in C C ontent o f A pples and I t s H e la tio n to Human
W e lfa re . S cien ce 831325«
8.
E h e a r t, M. S.
1 9 4 l. F a c to rs Which A ffe c t th e V itam in C C ontent o f A p p les.
V ir g in ia A gr. Exp. S ta . Tech. B u ll. 69.
•
9«
F e l l e r s , C. K.
1934. Fundam ental K u t r i t i v e Value o f A p p les. M a ssa c h u se tts F r u it
Growers A ssoc. E p t. 4 0 :1 8 1 .E x p .S t a . Record 7 2 :8 8 0 .(1 9 3 5 )
10.
______________ , C le v ela n d , M. M ., and C lag u e, J . A.
1933« V itam in C C ontent o f B aldw in A pples and A pple P r o d u c ts .
J . A gr. R esearch 46:1039-
11.
______________ , I sham, P . D ., and Sm ith, G; G.
1932. V itam in C D is tr ib u tio n i n B aldw in and M cIntosh A p p les.
Am. Soc. H o rt. S c i. P r o . 29:93«
12.
F is h , V. B.
1943. The E f f e c ts o f S to ra g e Upon th e A sc o rb ic A cid C ontent o f
Some West V ir g in ia A p p les. Am. Soc. H o rt. S c i. P r o . 43: 73»
- 47 13»
____________ * Eastman, B. B ., and M arsh, E. S.
1944. A scorM c A eid C ontent o f S e v e ra l V a r ie tie s o f A pples Crown
i n West V irg n ia . Am. Soc. H o rt. S c i. P ro . 44:196. -
1 4.
P i s h e r, B. A ., and Y a tes, F.
1943. S t a t i s t i c a l T a b le s f o r B io lo g ic a l, A g r ic u ltu r a l and M edical
B esearch.. O liv e r and Boyd L t d . , London, E ngland.
1 5.
C iv e n s, M. H ., McClugage, H. B ., and Van H om e, E. C.
1921. A n tis c o r b u tic P r o p e r ty o f Baw, D ried , and Cooked A pples and
B ananas. Soc. E x p t. B io l, and Med. P ro c . 1 8 :l4 0 .E x p .S ta .B ecord
4 5 :4 6 b . (1921)
46.
19-22.
*
.. * and
The A n tis c o r b u tic P r o p e r ty o f E m i t s I I . A n-E xperim ental Study
o f A pples and B ananas. Am. J . D ise a se s C h ild re n . 23:210.
E x p .S t a .B ecord 47:268. (1922)
1 7.
C o rtn e r, B. A.
193s * O u tlin e s o f B io c h e m istry . Jo h n W iley and Sons, Hew York.
1 8.
Could, H. P .
1944. A pple P ro d u c tio n by V a rie ty . Am.E m it Crower 6 4 :6 .B io l.E x tr a c ts
1 9 :4 0 . (1945)
19*
C ro ss, E,
1943. V itam in C S tu d ie s o f A p p les, Chem .Zentr. 11:2322.
C.A. 38:6413. (ig 4 4 )
20.
H a lle r , M. H.
1929. Changes i n th e P e c t i c C o n s titu e n ts o f A pples i n D e la tio n to
S o fte n in g . J . A gr. B esearch 39:739»
21.
H e s s le r, M. 0 . and C ra ig , C.
1929. V itam in C C ontent o f S pinach and Jo n a th a n A p p le s. M isso u ri
A gr. Exp. S ta . B u ll. 272:67. Exp. S ta . Be co rd 6 2 :9 5 . (1930)
22.
_______________ , and W illiam s, Z.
1929* The A n tis c o r b u tic P r o p e r ty o f A pple and E hubarb. M isso u ri A gr.
Exp. S ta . B u ll. 272:6S. E xp.S ta . Be cord 6 2 :9 5 . (1930)
2 3.
Johnson, S. E.
1929. The M cIntosh Apple In d u s tr y i n W estern M ontana. M ont.A g r.Exp.
S t a . B u l l .218.
24.
K e rte s z , Z. I . , C reen, E .L .
1931* F a c to r s In f lu e n c in g th e P e c tin C ontent o f S to re d Apple Pomace.
T e c h .B u ll. 179» Geneva, Hew York.
•
- 4g 25.
K e s s le r , W.
1939 . The V itam in O C ontent o f German A pple V a r ie t ie s and I t s
Dependence on H a b ita t, L ig h t I n t e n s i t y , F e r t i l i z i n g , D en sity
o f F r u it Hanging, and S t o r a g e .■
G artenhauw iss 1 3 : 619 . C.A. 34:1409« (1940)
26.
K eys. 0 . H.
'
1941. A H ote on th e S t a b i l i t y o f Vitam in C (A sco rb ic A c id ) in C itru s
J u ic e s . Hew Z ealand Med. J . 4 0 :3 7 9 . C.A. 3 6 :2 9 4 4 .(1 9 4 2 ) .
27.
___________ .
1942. V itam in C i n A p p les and O ther M a te r ia ls . Hew Z ealand S c i .
T ech. 2 4 :1 4 6 . H u tr itio n A b s tr a c ts & Eeview s 1 3 :5 6 7 . (1943)
28.
K ing, 0. G.
1936. V itam in C, A sc o rb ic A cid . ■P h y s io l. Eev. 1 6 :2 3 s.
C. A. 30:8313. (1936)
29.
Kohman, E. F . , Eddy, W. H ., C a rlss o n , V.
1924. I I , The V itam in C D e s tr u c tiv e F a c to r i n A p p les. In d . & Eng.
Chem. 16:1261. E z p .S ta.K ecord 5 3 '5 6 6 . (1925)
30.
K o le sn ik , A.A:.
1932. V itam in C i n A p p les. B iokhim iya 3 :6 7 3 . C.A. 33:2602. (1939)'
31.
L ee, W. G.
1945. P e rs o n a l Communication.
. .
32.
L o e f f l e r , H. J . , P o n tin g , J.D .
1942. A sc o rb ic A cid D e te rm in a tio n i n F re sh ,. Frozen o r D ehydrated
F r u i t s and V e g e ta b le s. In d . & Eng. Ghem. l4 :S 4 6 .
33»
M a n v ille , I . A ., McMinis , A. S ., and C huinard, F. G.
1934. V itam in S tu d ie s on A p p les. J . Am. D ie te t ic s A sso c. 10:135»
34.
--------------
---------------------------------- 1 ------------------ » ------------------- :---------------------------------------------- 1
1936.
V itam in S tu d ie s on A pp les.
—
I --------------------------------i—
:----------------------------- ♦
Food R esearch 1 :1 2 1 .
35»
M arsh, R. S.
,
1943. P r e lim in a r y R eport on S tu d ie s C oncerning th e n u t r i t i o n a l Value
o f A p p les. Ezp. S ta . R ecord 8 9 :3 9 4 .
36.
Maynard, L. A ., and B eeson, K. C.
1943. Some Causes o f V a r ia tio n i n th e V itam in C ontent o f P la n ts Grown
f o r Food. M u tritio n A b s tra c ts and Reviews 13:155«
37-
H e lle r , J . R ., St John, J . L ., and R ow ell, R. R.
1925. H o r t i c u l t u r a l I n v e s tig a t io n s a t th e W ashington S ta tio n , Wash.
C ol. Ezp. S ta . B u ll. 196. I z p . S ta . Record 54:835« (1926).■
I
r
.
38.
39«
-
49
-
P fund, M., 0 .
1939. The C u lin a ry Q u a lity o f A pples as D eterm ined hy th e Use o f
Hew Tork S ta te V a r i e t i e s . C o rn e ll S ta . Memoir 225.
P o t t e r , Cr. I*.
. 1935« A pple S to ra g e .
(1936)
'
Am. P r u i t Grower 5 5 :5 . E x o .S t a . Becord 74:205.
40.
P o t t e r , M.
1933* The Winesap A pple a s a Source o f V ita m in -C.
J . Home Econ. 2 5 :5 2 . "
41.
Pasm ussen, E . J .
1937. E f f e c t o f D elay i n S to ra g e and S to rag e T em perature on th e
K eeping Q u a litie s o f A pples. -U n iv e rs ity .of H.H. E x p .S ta .B u l l . 67.
42. 'B i v ie re , G. and P i ch ard , G.
1921. The l i g h t F a c to r i n A pple S to ra g e .
J . Soc. H a t i l . H o rt, F ran ce 4 :1 8 0 . E xp.S t a . B ecord 45:641. (1921)
43.
Buhner, M.
■
1916. The H u t r i t i v e V alue and Cost o f Some Im p o rtan t V e g e ta b le s.
. B e r l in . K lin . Wchnschr. ,53:385« E x p .S ta .B e c o r d ' 41:557. (191.9)
44.
Singh, B .S.
1943« S to ra g e o f A pples i n Kumaun. In d ia n Farm ing 4 :7 4 .
B i o l . A b s tr a c ts 1 9 :15 4 . (1945)
45.
Sm ith, G. G. and F e l l e r s , C. B.
1935» V itam in C C ontent o f Twenty-one M assa c h u se tts Grown V a r ie tie s
o f A p ples. Am. Soc. H o rt. S e i. P ro . 31:89-
46.
Smock, B. M., and Boynton, D.
1944.. E f f e c ts o f D i f f e r e n t i a l H itro g e n T reatm ent i n th e O rchard on
th e K eeping Q u a lity o f M cIntosh A p p les. Am. Soc. H o rt.
S c i . P ro . 45:85.
47.
S nedecor, G. Wi
.
1937« S t a t i s t i c a l M ethods. C o lle g ia te P r e s s , I n c . , Ames, Iowa.
48.
T odhunter, E. H.
1935» V itam in V alues o f Some V a r ie tie s o f A p p les. P ro c . Wash. S ta te
H o rt. A ssoc. 31s t M eeting. C. A. 30:5670. (1936)
49.
____________ .
1936. Some F a c to rs I n f lu e n c in g A sc o rb ic A cid (V itam in C) C ontent
o f A p p le s. Food B esearch 1:435-
50.
'________________ .
1937. The H u t r i t i v e V alue o f A p p les.
Wash. A gr. E x p .S ta .B u ll.1 5 2 .
- 50 51.
U. S., D ept, o f A g r., D iv .o f Crops and L iv e sto c k E stim a te s,H e le n a ,M o n t.
1935« M ontana S p e c ia l E ru.it Survey.
52.
West, C. and Z i lva, S. S.
1944. S y n th e s is o f V itam in C i n S to re d A pples. Biochem. J . 53:105.
53«
W inton, A. L. and Winton, K. B.
1935. S tr u c tu r e and C om position o f Foods, V ol. 11:559»
54.
Z ilv a , S. S ., Kidd, F . , West, C ., P e r r y , C. 0 . V.
1935. V itam in 0 C ontent o f Apples* D ept. S c i. In d . Hese a rc h ,
B p t. Food I n v e s t. B oard 1934. 164. C. A. 3 0 :1 7 9 . (1936)