A study of the time-temperature relationships in the cookery of vegetables
by Alda Constance Torgerson
A THESIS Submitted to the Graduate Committee in partial fulfillment of the requirements for the
degree of Master of Science in Home Economies
Montana State University
© Copyright by Alda Constance Torgerson (1933)
Abstract:
no abstract found in this volume A STUDY OF THE TII®-TEMPERATURE RELATIONSHIPS
■■ IN THE COOKERY OF VEGETABLES '
by
ALDA C. TORGERSON
, A THESIS
Submit fed. to th e G raduate Committee in p a r t i a l
f u l f i l l m e n t o f the necLUirements f o r
■ th e d eg ree o f M aster o f S oienee
in Home Economies a t
Montana S ta te C o lleg e
Approved:
^
I
ip
—
- ---------
In Charge of M ajor Work
Chairm, . Examining^ommittefe
Chairman G raduate Committee
Bozeman, Montana
Ju n e, 1933
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I
TABLE OF CONTENTS
INTRODUCTION ...................................................................
HISTORY................................................................................
page
3
5
EXPERIMENTAL PROCEDURE............................................
11
Methods o f c o o k i n g ............................................. 11-12
E q u ip m e n t....................................................................12-16
Methods o f t e s t i n g cooked v e g e ta b le s . . 16-17
RESULTS................................................................................
18
Cooking d a ta
f o r c a r r o t s ................................ 18-28
Cooking d a ta
f o r p o t a t o e s ........................... 28-37
Cooking d a ta
f o r b e e t s .................................... 37-39
Cooking d a ta
f o r o n i o n s ................................ 39-44
Cooking d a ta
f o r c a b b a g e ................................ 44-50
DISCUSSION.......................................................................
57
SUMMARY................................................................................
64
CONCLUSIONS.......................................................................
67
ACKNOWLEDGMENTS..............................................................
68
LITERATURE CITED
69
..........................................................
44544
■A STUDY OF' THE TIIEB-TEMPERATURE RELATIOHSHIPS
IH THE COOKERY OE VEGETABLES
IHTRODUOTI OH
V eg e tab le s a re no lo n g e r e o n sl l e r e d as a c c e s s o r ie s to
a m eal, b at have come ,to be re g a rd e d as e s s e n t i a l s in th e
d a i l y human food su p p ly ,
Phey, ran k n e x t to c e r e a l s in t h e i r
c a rb o h y d ra te c o n te n t and a re c l a s s e d w ith f r u i t s a s an im­
p o r ta n t so u rc e of m in e ra ls and v ita m in s B and C.
In a d d i tio n ,
t h e i r p le a s in g f l a v o r s , - d i s t i n c t i v e c o l o r s , and c e l l u l a r te x ­
tu r e make them a t t r a c t i v e and s tim u la te th e a p p e t i t e .
W hile a number of th e v e g e ta b le s may be u se d in the raw
s t a t e , many o f them r e q u ir e cooking i n o rd e r to' be e d ib le .
However, B o g e rt ( 2 ) sa y s * "V eg e tab les are more abu sed in
cooking th a n any o th e r c l a s s of fo o d s.
I t i s no wonder t h a t
p eo p le r e f u s e , t o e a t th e u n p a la ta b le messes w hich a r e u s u a lly
se rv e d up in th e name o f v e g e ta b l e s , b u t t h i s i s th e f a u l t of
th e cook, n o t o f th e v e g e ta b le s ."
I t is a p p a re n t from such
a s ta te m e n t t h a t more c o n s id e r a tio n sh o u ld be g iv e n to th e
co o k ery o f v e g e ta b le s , in o rd e r t h a t th e y may be h an dled in
ways t h a t w i l l re n d e r them b o th n u t r i t i o u s and p a l a t a b l e .
Some a t t e n t i o n h as been g iv e n to them in c o n n e c tio n w ith
th e doss o f t h e i r n u t r i e n t s , e s p e c i a l l y m in e ra ls and v ita m in s ,
where m ethods of co o k ery , a d d itio n o f s a l t and amounts o f
-4-
Qpoking w a te r were c o n s id e re d ,
Changes in th e f l a v o r of v e g e ta b le s have been ta k en in to
acco u n t from th e s ta n d p o in t of r e t a i n i n g th e m ild f la v o r s and
p r e v e n tin g th e developm ent of s tr o n g f la v o r s duihing co o k in g .
There h a s a ls o been some e v id e n c e to in d ic a t e t h a t c e r ­
t a i n p r e c a u t i o n s » such as th e degree o f h e a t , th e le n g th of
th e cooking p e r io d , and th e a c i d i t y o f th e w a te r u sed , sh o u ld
be observ ed so t h a t th e o r i g i n a l g r e e n , y e llo w , r e d o r w h ite
c o lo r o f th e v e g e ta b le m ight be r e t a i n e d .
O c c a s io n a lly , v a rio u s a u th o r s have p u b lis h e d tim e - ta b le s
f o r th e co o k in g of v e g e ta b le s , b u t upon co m p ariso n , t h e i r r e ­
commendations' e i t h e r do n o t ag ree o r th ey s u g g e s t a wide ran g e
in tim e .
In o n ly a few c a s e s , has th e r e been any m ention o f
th e te m p e r a tu r e , f o r w hich th e tim e was s p e c i f i e d .
I t i s e v i d e n t, th e n , t h a t th e r e i s a need f o r more i n f o r ­
m atio n ab o u t th e te m p e ra tu re m a in ta in e d d u rin g v a rio u s methods
o f cook ery and th e r a t e of h e a t flo w in to th e v e g e ta b le s su b ­
je c te d to th e s e m e th o d s ,' so t h a t a p ro d u c t may be o b ta in e d
t h a t i s s a t i s f a o t o r i l y cooked.
F o r t h i s re a s o n , t h i s stu d y
h as been c a r r i e d on in c o n n e c tio n w ith the Home Economies De­
p artm e n t o f th e M ontana E xperim ent S ta ti o n , in an attem p t to
e s t a b l i s h some tim e -te m p e ra tu re r e l a t i o n s h i p s in th e cookery
Of v e g e ta b le s .
-5-
HISTOEY
P r i o r to 191-7, v e ry l i t t l e work had been c a r r i e d on to
d eterm in e th e n atu re - o f v e g e ta b le fo o d s and th e most s a t i s ­
f a c t o r y methods f o r t h e i r p r e p a r a t io n .
O utside o f r e c ip e s
in co o k -b o o k s, th e r e was l i t t l e p u b lis h e d m a te r ia l .
Then in 1917, P a rlo a . (14.) p u b lis h e d a b u l l e t i n on th e
cooking o f v e g e ta b le s , g iv in g some d e s c r ip tio n s of th e s t r u c ­
tu r e and co m p o sitio n o f th e p l a n t s and th e p r i n c i p l e s u n d er­
ly in g t h e i r p r e p a r a t io n f o r fo o d .
However, no e x a c t tim es
were m entioned f o r t h e i r cooking p e rio d s ' and o n ly th e sugges­
t i o n was- made t h a t th e y sh o u ld be cooked u n t i l te n d e r .
In a s e r i e s of ex p erim en ts c a r r i e d on l a t e r by H a llid a y
and Hoble ( 8 ) a t th e U n iv e r s ity o f C hicago, em phasis was
p la c e d on th e. le n g th o f th e co o k in g tim e, in r e l a t i o n to th e
l o s s e s o f n u t r i e n t s , f la v o r and c o lo r in v e g e ta b le s , when
th e y w ere cooked b y v a rio u s m ethods.
They d e f i n i t e l y recom­
mended c e r t a i n methods in o rd e r to a v o id th e s e l o s s e s ; and
a d v o c a te d a c e r t a i n range o f tim e f o r cooking each v e g e ta b le
w ith th e ad v ic e to "cook i t only u n t i l te n d e r " .
While c o n s id e r in g cooking m ethods and th e r e s u l t i n g
l o s s e s , th e q u e s tio n aro se as t o th e a d v i s a b i l i t y o f u sin g
s a l t d u rin g th e b o ili n g p r o c e s s .
Ianman and M inton ( I l ) in ­
v e s tig a t e d t h i s problem and co n clu d ed t h a t th e c o l o r o f vege­
t a b l e s was n o t n o tic e a b ly changed b y th e a d d itio n o f s a l t to
—6 ~
to th e b o ilin g w a te r .
W hile th e y found t h a t in some e a se s
th e r e was a g r e a t e r l o s s o f n u t r i e n t s due to th e p re se n c e o f
s a l t , th e r e a p p e a re d to be enough ad vantage in th e te x tu r e
and f l a v o r o f th e cooked v e g e ta b le s to w a rra n t i t s a d d itio n ■
a t th e b e g in n in g of th e cooking p e r io d .
In none o f t h e i r
w ork, ho w ev er, d id th e y m ention w h eth er th e s a l t had any e f f e c t
on th e te m p e ra tu re of th e cooking medium or w h eth er i t a f f e c t e d
th e le n g th of th e cooking p e r io d .
D a n ie ls ( 4 ) s t a t e d t h a t
c h e m ic a lly p u re . sodium c h lo r id e hag. no h a rd e n in g e f f e c t on th e
s u b sta n c e s o f w hich v e g e ta b le s are composed, b u t th e calcium
c o n ta in e d in most ta b le s a l t gave r e s u l t s s i m i l a r to th a t o f
cooking in h a rd w aters
Optimum tim es f o r cooking as d eterm in ed by s c o r in g , p e r ­
c e n ta g e lo s s e s in s o li d s and t o t a l ash when th e v e g e ta b le s
were cooked to a s a t i s f a c t o r y t e x t u r e , and th e H -io n c o n c e n tra ­
t i o n of th e w ate r a f t e r cooking were in c lu d e d in th e r e s u l t s
o f s tu d ie s co n d u cted by F i e l d , S e r v e r , and M iln er ( 6 ) on
some C a lif o r n i a f r u i t s and v e g e ta b le s ,
The optimum cooking
tim e , th e y s u g g e s te d , f e l l w i t h i n .t h e ra n g e s g iv e n by H a llid a y
and Z oble ( S ) w ith th e e x c e p tio n o f cabbage and tu r n ip s .
In a stu d y o f b ak in g v e g e ta b le s e l e c t r i c a l l y , Sw artz (19)
p o in te d o u t the tim e r e q u ir e d when th e v e g e ta b le s were baked
a t v a rio u s te m p e ra tu re Si.
When medium .p o ta to e s , u n p ee led ,
were p la c e d in an oven a t 500° F . , th e y were done in 40 min-
-7-
u te a , b u t a t 250° F . , th ey were hone in 3 - 3-g- h o u rs ,
Ho
method, was used, f o r s p e c i f i c a l l y d ete rm in in g when th e vege­
t a b l e s were done, as t h a t was b ased s o l e l y on th e ,o p in io n o f
th e i n v e s t i g a t o r .
S in o d a , Kodera and Oya (16) a ls o seem to re c o g n iz e a r e ­
l a t i o n betw een tim e and te m p e ra tu re in t h e i r s tu d y of th e
c r i t i c a l te m p e ra tu re in cooking sw eet p o ta to e s «,
They ad v ise
th e cooking o f th e sw eet p o ta to a t h ig h e r te m p e ra tu re s f o r .
s h o r te r tfmes. due to ' th e f a c t th a t, a m o rp h o lo g ic al change in
th e s t a r c h g r a n u le s i s o b serv ed a t te m p e ra tu re s h ig h e r th a n
80° C.
P o ly m e riz a tio n o f th e low er su g a rs b e g in s , and th e
t a s t e i s l a r g e l y in flu e n c e d by th e c o n te n t o f th e s e unknown
p o ly m e riz a tio n p r o d u c ts . (17)
A nother f a c t o r ,'to be c o n s id e re d in th e r e l a t i o n betw een
tim e and te m p e ra tu re in coo k in g i s a l t i t u d e .
At h ig h e r a l t i ­
tu d e s th e te m p e ra tu re of b o ilin g w ate r is lo w ered and th a t
n e c e s s i t a t e s an in c re a s e in th e cooking tim e .
T h ie sse n (20}
in h e r b u l l e t i n p u b lis h e d by th e Wyoming E rp e rim eh t S ta tio n
h as p r e s e n te d recom m endations, f o r c o o k in g 'v e g e ta b le s a t an
a l t i t u d e o f ab o u t 7000 f e e t above s e a l e v e l , b u t h e r-s u g g e s ­
t i o n s c o n c ern in g th e tim es o f cooking were n o t v e ry d e f i n i t e .
A lso in ju d g in g th e p o in t at" w hich th e v e g e ta b le s w ere done,
She m erely p ie r c e d them w ith a f o r k to t e s t t h e i r te n d e r n e s s .
A s tu d y o f th e tim e r e q u ir e d f o r cooking p o ta to e s a t an
a l t i t u d e o f 5000 f e e t above se a l e v e l was made by G i l l ( 7 ) ,
who o oneIuded t h a t th e s iz e o f th e p ie c e o f p o ta to i s - a f a c t o r ?
w hich in f lu e n c e s th e le n g th o f tim e ,- a o n e -in c h cube r e q u i r ­
in g 25 m in u tes o f b o ilin g and a tw o -in c h cu b e, SO m in u tes.
, A p p a re n tly , th e n , th e le n g th o f time r e q u ir e d tO' cook
a v e g e ta b le a t a c e r t a i n te m p e ra tu re d epends upon th e r a t e o f
h e a t flow o r h e a t p e n e tr a tio n in th a t v e g e ta b le a t t h a t p a r ­
t i c u l a r te m p e r a tu r e i
Some s t u d i e s o f th e r a t e of h e a t pene­
t r a t i o n in cooking have been made by Magoon and C ulpepper (12) ,
B igelow { I ) , and Thompson ( 2 1 ) b u t th e se have b ee n c h i e f l y
from th e. s ta n d p o in t o f the com m ercial canning o f f r u i t s and
v e g e ta b le s .
F o r m easu rin g th e r a t e o f h e a t p e n e tr a tio n ;
th e y i n s e r t e d e i t h e r therm om eters o r th erm o co u p les in to the
c e n te r o f th e ca n , b u t n o t n e c e s s a r i l y in to th e c e n te r o f
th e p ie c e s o f food m a t e r i a l .
C o n seq u en tly , t h e i r r e s u l t s
.
in d ic a te t h e .h e a t flow i n 't h e l i q u i d o r cooking medium as
w e ll as in th e f r u i t o r v e g e ta b le .
The same th in g m ight be
• s a id o f a stu d y a t Iowa S ta te C o lle g e , where R e d fie I d , I e ls o n
and S u n d e rlin (15) ex p erim en ted w ith h e a t p e n e tr a tio n in
m eats and v e g e ta b l e s , p ro c e s se d in g la s s c o n ta in e r s .
They
found t h a t th e v a r ia b le s u sed in c a n n in g as s iz e of j a r ,
c lo s e n e s s o f p a c k , i n i t i a l te m p e ra tu re and c o n s is te n c y o f
th e v e g e ta b le s have a d ec id ed in f lu e n c e on th e tim e r e q u ir e d
f o r p e n e tr a tio n o f th e h e a t to th e c e n te r of th e j a r .
Some w orkers have f e l t that, a method o f s ta n d a r d iz a tio n
.
-9-
was needed in o r d e r to d eterm in e when a v e g e ta b le had been
d e s ir a b ly cooked;
She o rd in a ry way o f p ie r c in g w ith .a fo rk
was req.Qgnized to be u n c e r ta in and s u b je c t to v a r ia n c e w ith
in d iv id u a l judgm ent.
In a tte m p tin g to s e t up a d e s ir a b le
s ta n d a r d f o r eoo,ked c a r r o t s , L a n d re th (10) u sed a V icot
a p p a ra tu s w hich m easured th e p r e s s u r e r e q u ir e d to d riv e a
n e e d le in to a cube of c a r r o t in f i v e seco n d s.
L a n c a ste r
and Sweetman (. 9 ) d eterm in ed th e nd o n en essn o f u n ifo rm s l i c e s
of p o ta to by means o f a p e n e tro m e te r.
I t c o n s is te d o f a b l u n t ,
u n ifo rm n e e d le w hich p e n e tr a te d th e cooked v e g e ta b le under a ■
"
te n gram w e ig h t. The amount o f p e n e tr a tio n in to th e v eg etab le,
•
was m easured;
They a ls o s tu d ie d th e speed and ev en n ess o f
cooking in r e l a t i o n to m a tu r ity , s i z e , p e rio d in s to r a g e and
v a r i e t y of p o ta to .
R e c e n tly a n o th e r p e n e tro m e te r h a s been
d e v is e d by th e U n ite d S ta te s Food and Drugs A d m in is tra tio n ,
I t a ls o has a b lu n t, u n ifo rm n e e d le which p e n e tr a te s th e c o o k - '
ed v e g e ta b le b u t th e w eig h t i s s u p p lie d by a w eighed f l a s k to
w hich m ercury i s added u n t i l a sm a ll l i g h t in d ic a t e s t h a t th e
n e e d le h as p e n e tr a te d to th e d e s ir e d d e p th .
The w eig h t of
th e f l a s k and th e m ercury i t c o n ta in s .is' re c o rd e d a s th e w eig h t
r e q u ir e d f o r p e n e tr a tio n o r an in d ic a tio n of th e te n d e rn e s s o f ■
th e v e g e ta b le .
These s t u d i e s com prise p r a c t i c a l l y a l l o f th e s c i e n t i f i c
work t h a t h a s been done a lo n g th e l i n e of v e g e ta b le coo k ery .
—1 0 —
I n v e s t i g a t Ions on th e r e l a t i o n o f tim e to te m p e r a tu r e ' or th e
r a t e o f h e a t p e n e tr a tio n have b een c a r r i e d on c h i e f l y in con­
n e c tio n w ith com m ercial c a n n in g .
Recommendations f o r th e tim e
o f cooking v e g e ta b le s by home m ethods a re n o t v e ry s p e c ific ,
w ith th e r e s u l t t h a t many v e g e ta b le s a r e o f te n p o o r ly cooked
and th e r e f o r e u n p a la ta b le .
In view of t h i s s i t u a t i o n th e r e a p p e a rs to be a need f o r
f u r t h e r a c c u r a te in v e s t i g a t i o n in th e f i e l d o f home cookery
o f v e g e ta b le s , p a r t i c u l a r l y in re g a rd to - th e r a t e of h e a t flo w
a t v a rio u s cooking te m p e ra tu re s .
-11-
EXPERIlM T A l PROCEDURE
Tiie v e g e ta b le s ehosen f o r t h i s stu d y were p o ta to e s * c a r r o t s ,
b e e t s , o n io n s and ca b b ag e, s in c e th e y a re commonly grown in
Montana and la r g e q u a n t i t i e s tif them are u s u a lly s to r e d f o r
w in te r consum ption.
These v e g e ta b le s were o b ta in e d from l o c a l tr u c k g ardens
'
'
where th e y were k e p t in ' p i t s and. r e a d i l y a v a ila b le d u rin g th e
w in te r months'.
The v a r i e t i e s u'sed th ro u g h o u t th e stu d y w ere: -
p o t a t o e s , STetted G-em? c a r r o t s , C hantenay; b e e t s , Dark Red;
o n io n s, True S p an ish ; a n d 1c a b b a g e , D anish B ald h ead .
Each v e g e ta b le was p re p a re d f o r cookery a c c o rd in g to c e r ­
t a i n ad o p ted m ethods,
The c a r r o t s were th o ro u g h ly washed w ith
a v e g e ta b le b ru s h , th e n some were s c ra p e d , w h ile o th e r s were
a llo w ed to r e t a i n th e s k in .
A sam ple w eighing ap p ro x im a tely
500 grams was u se d f o r each cooking t e s t .
E o r th e sam p les»
th e c a r r o t s were c u t as a c c u r a te ly a s p o s s ib le in to o n e -in c h
c u b e s , tw o -in c h c u b e s, and one by tw o -in ch p i e c e s , r e s p e c tiv e ­
ly .
The one by tw o -in c h p ie c e s were alw ays s e c u re d by c u t tin g
a tw o -in ch cube le n g th w ise..
The p o ta to e s w ere'w ashed and p e e le d w ith th e e x c e p tio n ■
o f th o s e t h a t were to be co o k ed . in th e ” j a c k e t s 11.
The 500-
gram sam ples o f p o ta to e s a ls o c o n s is te d o f o n e -in c h cubes and
tw o -in ch c u b e s , r e s p e c t i v e l y , w ith th e a d d itio n o f some sam ples
o f whole p o ta to e s , a p p ro x im a te ly two b y f o u r in c h es in size;.
-IE $he "beets were washed w e ll an d l e f t whole w ith th e skim on d u rin g co o k in g , f o r th e r e a s o n t h a t th e y " b le e d " when eut>
A measurement of th e d ia m e te r and le n g th of eaoh b e e t was
ta k e n .
,
Ih e o n io n s w ere washed and th e h ard o u te r l a y e r s were
p e e le d o f f b e f o r e co o k in g .
Ih e y were a ls o l e f t whole and
m easured f o r d ia m e te r and le n g th .
The cab b ag es w ere s tr ip p e d o f t h e i r c o a rs e o u te r le a v e s
and were th e n c u t in to q u a r te r s .
M easurem ents o f th e le n g th
and w id th of th e c u t s u r f a c e s w e re ■reco rd ed as th e s ic e o f
th e in d iv id u a l p ie c e s .
In a d d i tio n to d e te rm in in g th e w eig h t o f each sam ple,
i t seemed d e s ir a b le to o b ta in i t s volume,..
To do. th is ,, the
sample was p la c e d in a r e c e p ta c le of known volume and tap
w a te r was added u n t i l the low er m eniscus of th e w a te r was
on a le v e l w ith th e g ra d u a te d mark on th e r e c e p t a c l e .
The
d if f e r e n c e betw een th e volume ,of the. r e c e p ta c le and the v o l^
ume of th e w ate r added gave th e volume of th e sam ple of vege­
ta b le .
The m ethods of cookery used f o r th e se t e s t s were b o i l i n g ,
ste am in g , steam p r e s s u re c o o k in g , an d b a k in g , e i t h e r d i r e c t l y
o r in c a s s e r o l e s .
Eor b o ilin g ,..tw o covered aluminum sauce p a n s , of f o u r q u a r t c a p a c ity and s im ila r in s t r u c t u r e , were u sed as- u t e n s i l s .
-13-
TheI r r e s p e c tiv e w e ig h ts in c lu d in g co v ers w ere 332 and 335
gram s,
Two h o le s were Cut in th e co v er of each pan to p erm it
th e i n s e r t i o n of ru b b e r s to p p e rs h o ld in g , e i t h e r ch em ical t h e r ­
mometers o f therm ocouple w ir e s .
In most c a s e s , 750 c e . ,o f ta p
w a te r , w ith a pH o f 7 .8 , were p o u red in to each pan to s e r v e "a s
th e cooking medium..
T h is w a te r was ta k e n from a la r g e c o n ta in ­
e r w here th e w a te r h ad been s t i r r e d in o rd e r to b r in g i t to an
a p p ro x im a te ly u n ifo rm te m p e ra tu re .
The h eat was th e n s u p p lie d
by two 8 0 0 -w a tt C alro d p l a t e s on a H o tp o in t e l e c t r i c range
w ith th e c o n t r o ls tu r n e d to nM g h n .
These p l a t e s had p re v io u s ­
l y been c a l i b r a t e d to show t h a t th e y s u p p lie d h e a t at. eq u iv a­
le n t r a te s .
The pans o f w ater w ere p la c e d on th e h o t e l e c t r i c
p l a t e s a t a d e f i n i t e tim e , and when th e therm om eters,, suspend­
ed in th e steam over th e w a te r, in d ic a te d t h a t th e b o ilin g
p o in t c o rre sp o n d in g to th e b a ro m e tric p r e s s u r e h ad b een r e a c h ­
ed , th e sam ples o f v e g e ta b le were added and th e c o n tr o ls were;
tu rn e d to nmedium” .
,For steam in g th e v e g e ta b le s , a Conserve ste am e r was u se d .
T h is c o n s i s t s of a sq u a re copper w a te r-p a n (11 x 11 x 2 in c h e s)
surm ounted by a t i h - p l a t e d c a b in e t (1 2 x 12 x 3,8 in c h e s) hav­
in g f o u r w ire sh e lv e s and two d o o rs.
A fte r th e pan had been
f i l l e d w ith ta p - w a te r , th e steam er was p la c e d on one 8 0 0 -w att
C alro d p l a t e of th e E o tp o in t e l e c t r i c range w ith th e c o n tr a I
tu rn e d to " h ig h ” ,
When th e w ater was b o ili n g v ig o r o u s ly and
I
-14-
th e steam er f i l l e d w ftii steam , th e v e g e ta b le sa m p le s, a rra n g e d
in w ire b a s k e t s ,, were p la c e d on th e ,tw o upper s h e lv e s ,
$he
th erm oco u p les were in tro d u c e d th ro u g h an opening in one c o r n e r
o f th e to p , where o r d i n a r i l y a p ip e was i n s e r t e d f o r th e a d d i­
t i o n of more 'W ater 4/
.
,
• „
In steam p r e s s u r e co o k in g , th r e e s i z e s o f I f a tio n a l'P r e s s ­
u re Cookers were u s e d :- th e 10 q u a r t s iz e w eighing 9-g= pounds.,
w ith a t o t a l volume of 8560 c c .; th e 18 q u a rt s iz e w eighing
17i; p oun d s, w ith a t o t a l volume o f 18,900. c c . ; and th e 25
■
q u a rt s iz e w eighing 20 pounds, w ith a t o t a l volume o f 2 4 ,8 5 0 -'o ce
The amounts o f ta p w a te r added to each p re s s u re cooker f o r
each sample cooked w ere:.- 350 cei to . th e 10 q u a rt s iz e ; 500 e c .
to th e 18 q u a rt s i z e ; and 750 o e . to th e 25 q u a rt s i z e ,
In
each c a s e , th e h e a t was s u p p lie d by an 8 0 0 -w att C alro d p l a t e
o f th e H o tp o in t e l e c t r i c ran g e w ith th e c o n tr o l tu r n e d to
" h ig h " .
,
As soon a s th e w ater b o ile d v ig o r o u s ly , p ro d u cin g a
l i b e r a l amount o f steam , th e v e g e ta b le sam ples were put in to
th e c o o k e r, . The .s a f e ty - v a lv e in th e cover was removed and ■
a ru b b e r s to p p e r c a r r y in g th e in s u la te d th erm o co u p les was
t i g h t l y fo rc e d in to th e o p en in g ,
The co v er was th e n p la c e d
on th e cooker and th e w in g -n u t screw s c a r e f u l l y tig h te n e d ^
The p e t-c o c k was l e f t open and soon a ste a d y flo w o f steam
came from th e o p en in g .
T h is stream o f .steam was allo w ed to ,
co n tin u e:; f o r f iv e m in u te s, so th a t th e a i r m ight be co m p lete-
-15-
I y removed., th en th e p e t-c o o k was clo sed , and. th e p r e s s u r e was ■
allowed, to d ev elo p u n t i l a te m p e ra tu re of sb o 0 F . was reached^
E his te m p e ra tu re was m a in ta in e d w ith in th e p r e s s u r e co o k er a&
lo n g as d e s ir e d .
The d i r e c t "baking of th e v e g e ta b le s was c a r r i e d bn in a
H p tp q in t e l e c t r i c oven (14 x 1 8 -x 18 in c h e s ) ,p ro v id e d w ith an
a u to m a tic h e a t c o n t r o l . ' The c o n tr o ls of th e u p p er and lower
elem e n ts were tu r n e d to "high'? and th e oven was p re h e a te d to
375° Fe
Ehe sam ples were th en p la c e d on a ra c k h e l d in th e
e ig h th groove from th e bottom .
Ehe th erm o co u p les w ere b ro u g h t '
in to th e oven th ro u g h th e opening a t th e b ack d e sig n e d f o r
steam e s c a p e ,
Ehe e l e c t r i c i t y was th e n tu rn e d o f f th e upper
elem ent*
S in ce most o f th e v e g e ta b le s were n o t ad ap ted to d i r e c t
b a k in g , th e p la n of b ak in g v e g e ta b le s in c a s s e r o le s as d ev elo p ­
ed by Swartz. (19) was u se d ,
Four co v ered p y rex c a s s e r o le s ,
h av in g u n ifo rm volumes of I i q u a r ts and s im ila r w e ig h ts , were
se c u re d f o r t h i s purpose*
■
Ehe v e g e tab le;- sam ples were p u t
in to th e c a s s e r o le s and j u s t b e fo re th e y were p la c e d in th e
p re h e a te d oven, £50' e c . of h o t ta p w a te r were added to ea ch .
Ehe therm ocouples b ro u g h t in a t th e back o f th e oven were in ­
tro d u c e d in to th e c a s s e r o le s th ro u g h h o le s b o red in th e c o v e rs .
Eherm ocouples were used in ea ch cooking t e s t in o rd e r W .
d eterm in e th e r a t e o f h e a t flow in th e v e g e ta b le s .
' '
.
•
C e rta in
!!O iyno
;,i. !.,Vf c:-r i :
I
\
'i USbUiV
-16-
p ie c e s in each, sample o f v e g e ta b le were se le c te d , as t e s t
p ie c e s and. th e h o t-e n d .' ju n c tio n o f a therm ocouple was i n s e r t -1
ed. so t h a t i t s t i p j u s t reached, th e c e n te r of a p ie c e .
By
t h i s mean's th e te m p e ra tu re a t th e c e n te r could, be obtained,
a t one-m inute i n t e r v a l s .
The equipm ent used, f o r t h i s purpose ;
c o n siste d , of f o u r s i x - f o o t H oskins th erm o co u p les, h ig h r e s i s t ­
a n c e , Ho. 22 B & S gauge and. a s b e s to s in su la te d ..
By means of
fo u r H oskins f l e x i b l e .le a d s , o f h ig h r e s is ta n c e ty p e and s ta n ­
dard le n g th , th e s e th erm o co u p les w ere con n ected to a f o u r- p o in t
s e l e c t i v e s w itc h , w hich in tu r n was connected to a Ho sk in s py.
ro m e te r, ty p e TA. 55QP F . , h ig h r e s i s t a n c e , w ith au to m atic c o ld
end com p en satio n .
While cooking th e v e g e ta b le s by b o i l i n g , ste a m in g , or
bak in g th e te m p e ra tu re a t th e c e n te r o f th e v e g e ta b le g rad u ally approached th e b o ilin g p o in t o f w a te r and t h i s te m p e ra tu re was
m a in ta in e d u n t i l th e cooking p ro c e s s was com pleted.
The amount
o f tim e t h a t was r e q u ir e d a t th e b o ili n g te m p e ra tu re v a rie d
w ith th e v e g e ta b le and th e method o f cooking*
A group o f fo u r' ju d g es from th e Home Econom ics D epartm ent
of th e E xperim ent S ta tio n sc o re d the cooked v e g e ta b le s .
The ■
v e g e ta b le s were f i r s t allo w ed to c o o l so t h a t th e h e a t would
n o t mask th e f l a v o r .
Ju d g in g sh e e ts' were' s u p p lie d w ith each
sam ple to be sc o re d .
Each s h e e t c o n ta in e d a g r a d in g sc o re
b ased on te n d e r n e s s , t e x t u r e , f l a v o r and c o l o r .
Each o f th e s e
-Vifr?**
f a a t o r s was in , tu r n divided, in to s i x g r a d a tio n s , b e g in n in g
w ith th e most d e s i r a b l e .
In a d d i tio n to- th e ju d g in g of eaph sample of cooked
v e g e ta b le s., a p e n e tr a tio n , t e s t f o r te n d e rn e s s was made on a t
'
'
.
'
l e a s t th r e e p ie o e s from each sample w ith a p e n e tro m e te r.
T his p ie c e o f equipm ent was d e v is e d by, members of th e Food
and Drug A d m in is tra tio n o f th e U n ite d S ta te s D epartm ent of
A g ric u ltu r e to use in -d e te rm in in g th e te n d e rn e s s o f foods
u n d er th e p r o v is io n s o f th e McHary-Mapee am endm ent"to th e
F e d e r a l food and d rugs a c t .
• 1
The l i q u i d rem ain in g in th e cooking v e s s e l a t th e com­
p l e t i o n o f each- ex perim ent wa.s t e s t e d f o r i t s ' pH v a lu e by
th e c o lo rim e te r method su g g e ste d by O lark ( 0 j .
T his s e r i e s o f t e s t s h as b een a p p lie d to th e v e g e ta b le s
s e le c te d f o i t h i s s tu d y and to v a r io u s - s iz e d p ie c e s - o f th e s e v e g e ta b le s , f o r th e purpose o f com paring t h e i r tim e-tem p era­
tu r e r e l a t i o n s h i p s d u rin g co o k ery .
-18-
BESULIS
In p r e s e n tin g th e r e s u l t s o f t h i s 'i n v e s t i g a t i o n , a s e r i e s
o f .ta b le s w i l l he u se d , g iv in g th e d a ta f o r th e co o k in g of each
v e g e ta b le by th e v a r io u s m ethods, and o th e r r e s u l t s th a t accom­
p a n ie d th e s e t e s t s .
These w i l l be supplem ented by a s e t o f
g rap h s showing th e h e a t flow th ro u g h th e v e g e ta b le s o r the.
tim e -te m p e ra tu re r e l a t i o n s h i p s e x i s t i n g d u rin g t h e i r cookery.
T able I shows th e av erag e r e s u l t s o b ta in e d in th e cooking
of c a rro ts .
I t w i l l be n o te d t h a t ' i n th e b o i l i n g o f c a r r o t s ,
some sam ples were cooked in ta p w a te r w ith o u t s a l t , w h ile in
o th e r c a s e s s a l t was added to th e w a te r a t th e b e g in n in g of
th e co o k in g p e r io d .
I n two in s ta n c e s d i s t i l l e d w a te r was u se d
in p la c e o f ta p w a te r, b o th w ith and w ith o u t s a l t .
In
o b se rv ­
in g th e av erag e number o f m in u tes r e q u ir e d to cook th e se v a r io u s
sam ples u n d er th e c o n d itio n s s p e c if ie d in th e t a b l e , i t w i l l
be se en t h a t the. s iz e of p ie c e a f f e c t s th e le n g th o f th e cook­
in g tim e , th e l a r g e r th e p i e c e , th e lo n g e r th e tim e .
The a d d i­
t i o n o f s a l t to th e ta p w ate r a p p e a rs to have no e f f e c t upon
th e t o t a l co o k in g tim e .
.
W ith d i s t i l l e d w a te r, b o th w ith and
w ith o u t s a l t , th e r e a r e some in d ic a t io n s t h a t a s l i g h t l y
lo n g e r cooking tim e i s n eeded.
When th e 2 x 2
in c h p ie c e s -
o f c a r r o t a re cooked w ith, th e s k in s on, in s te a d o f b eing s c ra p ­
ed , th e y seem to r e q u ir e a lo n g e r cooking p e rio d ^
A lthough
th e bak in g o f v e g e ta b le s in c a s s e r o le s in th e oven, has been
-19-
EABIE I .
COOKHa DATi FOR CARROTS .
Method
of
Cooking
C o n d itio n
of
C a rre t
B o ilin g
«
n
n
U
ii
K
It
It
It
n
it
Steam ing
ii
,
a
n
Baking*
it
P ,C f* 10 q t .
"
18 ’n
B 25 «
ti
io "
n
I8 »
ti
25 n
«
10 n
ti
I 8 ii
"
25 «
' "
10 »
«
18 «
”
25 “
sc ra p e d
a
ii
it
tu
Tl .
Il
w ith s k in s
it
n
K•
It
Il
H
sc ra p e d
ii
w ith s k in s
it
it
sc ra p e d ,
it
!
n
n
n
it
K
Tl '
It
It
Tf
w ith s k in s
it
it
Tl
TI
Bo.
of
T r i a ls
4
2
8
4
’
2
S
10
6
2
2
2
2
4
8
4
4
5
5
I
I
I
I
I
I
I
I
I
I
I
I
,* Baking in covered e a s a e ro le
** Steam p r e s s u r e opoking
A v.Size
P ie c e
' in .
Av. Wt. “ A v.V ol.
Sample
Sample
gms.
e . e.
I x l
503.0
1 x 2
531.0
5 4 7 .6 .
2 x 2
-,l;yx'\l !■ 501.5
528.0
I x 2
512.7
2 x 2
5 2 4 .4
2 x 2
•518; Q
2 x 2
543.0
1 x 2
,2 x 2
563.0
5 5 3 .0 ,
1 x 2
563.0
2 x 2
4 9 0 .0
I x l
.5 1 1 .4
2 x 2
527.5
1 x 2
517.5
2 x 2
I x l
501.6
514.7
2 x 2
4 6 3 .5 .
I x l
506.0
'1 x 1
498.0
I x l
535.0
1 x 2
5 3 3 .4
1 x 2
518.5
1 x 2
2 x 2
537 .4
2 x 2 - 531.3
537 .5
2 x 2
550.5
2 x 2
2 x § . 579.0
2 x 2
550.0
600
660
585
575
640
608
610
617
620
750
640
750
625
648
635
655
636
637
610
600
660
660
640
660
640
670
520
590
660
Kind
of
W ater
V ol. of
W ater
0 ,0 ,
ta p
TI
it
Tl
It
' It
d is tille d
it
ta p
it
n
it
n
Tl
TI
It
Tl
It
IT
Tt
, Tl
TI
TI
Tl
It
TI
II
ft
Tl
It '
750
750
750
750
750
750
750
750
750
750
750
750
1000
1000
100 Q
1000
250
" 250
350
500
750
350
500
750
350
500
750
350
500
750
Wt i o f
S a lt
. gms.
'
——
——
5
5
5
5
*
5
5
—
——
-——
——
——
——
——
—
——
--
Cooking 'Av. Bo,
Temp.
M inutes .
Cooked
0F .
2 0 3 .2
2 0 2 .8
2 0 3 .4
203.2
2 0 2 .8
2 0 2 .4
202,9
203.1
2 0 2 .1
2 0 2 .1
2 0 2 .1
2 0 2 .1
202.9
2 0 3 .1
203.3
203.3
202.4
20 2 .4
250.0
250.0
250.0
250.0
250.0
250.0
250.0
2 5 0 .0
250.0
250.0
250.0
250.0
30
35
40
30
35
38
42
42 ■
35
44
35
44,
35
44
40
46
82
90,
3
3
3
5
4
4
6
5
, 5
12
^ ll
10
- 20—
recommended b j some w o rk e rs , th e tim e needed to cook c a r r o t s
"by t h i s method , i s tw ic e as lo n g as f o r b o ili n g .
The tim e f o r
steam p r e s s u r e cooking i s n o tic e a b ly s h o r t , in f a c t , about oneh a l f as lo n g as th e tim e u s u a lly su g g e ste d f o r c a r r o t s a t
250° IP. in th e tim e - ta b le s .
F ig u re s I , 2 , 3 , 4 , 5, 6 and 7 show a g r a p h ic a l r e p r e s e n ta ­
t i o n o f th e av e ra g e h e a t flow in cooking c a r r o t s by th e se v a r­
io u s m ethods.
These g rap h s a re p l o t t e d from th e therm ocouple
re a d in g s ta k e n a t i n t e r v a l s o f one o r two m in u t e s .' In f ig u r e I
a com parison o f th e h e a t flow in p ie ces o f sc ra p e d c a r r o t o f
d i f f e r e n t s iz e s shows a sh arp cu rv e in th e ca se o f th e sm a lle r
p ie c e and a more g ra d u a l curve in th e l a r g e r p ie c e s .
When
s a l t i s added to th e cooking w a te r th e t o t a l coo k in g tim e i s
th e same a s f o r u n s a lte d w a te r and the- h e a t c u rv e s a r e v ery
s im ila r.
I t w i l l be n o te d in f ig u r e 2 t h a t th e r a t e o f h e a t
flow in c a r r o t s i s th e same when th e coo k in g medium
is e ith e r
ta p w a te r or d i s t i l l e d w ater w ith o u t s a l t , b u t th e a d d itio n
o f s a l t a p p e a rs to cause a s h a rp e r r i s e w ith ta p w ate r th a n
w ith d i s t i l l e d w a te r.
In f ig u r e 3 , cu rv es are shown when th e
s k in s were l e f t on th e c a r r o t s d u rin g th e b o ili n g p ro cess'.
S ince th e 1 x 2 in c h p ie c e s were p re p a re d by c u t tin g a 2 x 2
in c h p ie c e s le n g th w is e , th e s k in : was l e f t on o n ly one s id e
and th e tim e f o r b o ili n g was th e same as f o r b o i l i n g th e
sc ra p e d I k 2 in c h p ie c e s (see f ig u r e I ) .
The 2 x 2
in ch
-21TCMR
F0
Tap w a te r without salt
30
Top watt.' with salt
40
TIMC — M IN U T E S
F ig .
I.
C u rv es show ing t h e t i m e - te m p e r a tu r e r e l a t i o n s h i p s
d u rin g th e b o ilin g of sc rap ed c a r r o t s , cu t in to
p ie c e s of v a rio u s s i z e s , in tap w a t e r , w ith o u t
and w ith s a l t .
-22temp.
Tap w a t e r
Distilled water
W ithout salt
TIM E —
F ig .
2.
W it h
salt
M IN U T E S
C u rv es show ing th e ti m e - t e m p e r a t u r e r e l a t i o n s h i p s
d u rin g the b o ilin g of sc ra p e d c a r r o t s in ta p w ater
and d i s t i l l e d w a te r w ith o u t and w ith s a l t .
—2v>-
f •
230
Ibp w ater without salt
210
la p w a ter with salt
190
170
150
130
no
90
70
J_________ I_________I_________I_________I_________I_________L
50
IO
F ig .
2.
20
30
40
TIME: — M IN U T E S
50
C urves show ing th e tim e -te m p e ra tu re
(luring th e b o i l i n g o f c a r r o t s , w ith
ta p w a te r w ith o u t and w ith s a l t .
GO
70
relatio n sh ip s
sk in on, in
-24TEMR
E °
Car >'oto - Scraped
190
C a rro \s with shins
—
TIM E
F ig . 4 .
—
M IN U T E S
Curves showing th e tim e -te m p e ra tu re r e l a t i o n s h i p s
d u rin g th e steam ing of c a r r o t s , sc ra p e d and w ith
s k in s .
-25-
"^CMP
F°
40
50
TIM 5 — M IN U T E S
F ig . 5.
C urves showing th e tim e -te m p e ra tu re r e l a t i o n s h i p s d u rin g th e baking
of sc ra p e d c a r r o t s in c a s s e r o l e s .
-26-
CMR
ir°
/ /
40
TIME —
F ig . 6 .
2 5 q u a rt
P. C.
50
M IN U T E S
Curves showing the tim e -te m p e ra tu re r e l a t i o n s h i p s d u rin g th e cook­
in g of sc ra p e d c a r r o t s in p r e s s u r e co o k e rs o f th r e e s i z e s .
-27-
TEMR
F°
/ ------ Carrot scraped
------ Carrot shins on
IO q u a r t P . C .
■ / 1 8 quart
TIME: —
F ig . 7.
R .C / / 2 5 q u a rt
P. C.
M IN U T E S
Curves showing th e tim e - te m p e ra tu re r e l a t i o n s h i p s
d u rin g th e co o k in g of c a r r o t s , sc ra p e d and w ith
s k in s on, in p r e s s u r e co o k ers of th r e e s i z e s .
-28-
p ie c e c o m p le te ly e n c ir c le d by s k in ap p e ars to have a slow er
r a t e o f h e a t flo w , b o th w ith and w ith o u t s a l t in th e cooking
l i q u i d , and t h i s r e s u l t e d in a lo n g e r cooking p e r io d .
I t w i l l be seen in f ig u r e 4 t h a t steam ing a p p e ars to
cause a la g
th e h e a t flow in sc ra p e d c a r r o ts when compared
to t h a t o f b o ilin g and th e t o t a l tim e i s lo n g e r .
When th e
s k in s a re l e f t on, how ever, th e r a t e o f h e a t p e n e tr a tio n more
n e a r l y ap p ro ach es t h a t d u rin g b o i l i n g .
There i s
n o tic e a b le la g in the. h e a t flo w when c a r r o ts
a re baked in c a s s e r o le s as in d ic a te d in f ig u r e &.
A gain1, th e
s iz e of p ie c e makes some d if f e r e n c e and th e t o t a l tim e i s
double t h a t of b o i l i n g .
F ig u re 6 r e p r e s e n ts a com parison of th e tim e f o r cooking
v a r io u s - s iz e d p ie c e s o f c a r r o t s in th re e s iz e s o f p re s s u re
c o o k e rs .
e s t tim e .
In each ea se th e s m a lle s t p ie c e r e q u ir e d th e s h o r t ­
A ll o f th e g rap h s a re much s te e p e r th a n in any
o th e r method o f booking.
A com parison o f th e p r e s s u r e cooking
o f 2 x 2 in c h p ie c e s o f c a r r o t s w ith and w ith o u t s k in s i s
shown in f ig u r e 7*
The h e a t flow in th e p ie c e s w ith s k in s
a p p e ars t o be much more r a p id when cooked in th e 10 q u a rt
and 18 q u a rt p r e s s u r e c o o k e rs , but ab o u t th e same as th e
sc ra p e d c a r r o t in th e '25 q u a rt p r e s s u r e co o k er.
T able I I g iv e s th e av erag e r e s u l t s - t h a t were found in
th e cooking o f p o ta to e s .
A gain i t w i l l be n o te d t h a t in b o i l -
S '
—2 9 —
TABLE L I.
Method
of
Cooking
B o ilin g
Tl
TT
Tl
Tl
n
■
COOKIUG BATA FOR POTATOES.
C o n d itio n
of
P o ta to .
p e e le d
Tl
ii
n
it
w ith s k in s
p e e le d
IT
w ith s k in s
Steam ing
p e e le d
Tl
Tl
ii
Baking*
Tl "
: ■v
I?
w ith s k in s
P .c f * 10 g.ti p e e le d
ii
"
18 ii
it
n
lt
25.
it
"
10 M
n
*
18 «
ii
n- 25
" I
Tl
Ho,
of
T ria ls
4
4
4
4
4
4
4
4
4
4
4
4
4
I
I
I
I
I
I
* B aking in covered Q a sse ro le
* Steam p r e s s u r e cooking
A v.S ize
P ie c e
in .
-
Av. Wt ♦
Sample
gms.
501.5
I x l
2x2
1493.0
I x l
, 502.5
2x2
525.0
s f x i i 5 0 5 ,5
s i x i i 514.5
4 8 6 .5
8 : 8 53.0.0
I X l
499.0
2x2
4 9 7 .5
I x l
505.0
2 x 2
497.0
Si x 2
560.0
510.0
I x l
I x l
506 .0
I x l
505,0.
550.0
2x2
510.0
2 x 2
2 x 2
490.0
•
A v.V ol.
Sample
C • c©
'
590
565
558
§70
555
550
553
588
568
540
553
. 545
465
550
545
560
590
550
560
Kind
' of
Water
Y ol. o f
W ater
c id .
ta p
it
it
Jt
It
"
Tl
TT
it
ii
it
Tl
It
It
It
It
.
n
n
it
it
~
750
- 750
750
750
1000
1000
1000
1000
1000
io o o •
250
250
350
500
750
350
500
750
'
Wt. o f
S a lt
gms.
>
■
5
5
—•»
5
5
——
mm mm
~m m
mm
Wn
'WWp
WW
WW
——
Cooking
Temp.
op.
202.6
202.6
202.6
202.6
202.8
2 0 2 .4
202.8
2 0 2 .4
202.8
202.8
20 3 .4
2 0 3 .4
350:4)
25010
250.0
250.0
250.0
250.0
250.0
Av. Ho.
M inutes
Cooked
20
42
20
42
42
40
42
40
32
44
52
52
56
3
3
3
.1 2
- U
10
—S G -
ing. th e I x .1 in c h p ie c e r e q u ir e s a much s h o r te r cooking tim e
th a n th e 2 x 2
in c h p i e c e , in t h i s ca se l e s s th a n o n e -h a lf th e
tim e i s n eed ed .
The a d d itio n o f s a l t t h th e co o k in g li q u i d
a p p e a rs to have no e f f e c t on th e tim e.
The p e e le d whole p o ta ­
to e s a p p a r e n tly r e q u ir e a l i t t l e more tim e th a n th e whole
p o ta to e s t h a t a re cooked w ith th e s k in s on.
th e I x l
The steam in g of
in c h p ie c e demands a d i s t i n c t l y lo n g e r tim e th a n
f o r b o ili n g b u t th e 2 x 2 in c h p je c e ap p e ars to n eed v e ry
l i t t l e more tim e .
B aking a g a in r e q u ir e s th e lo n g e s t tim e o f
a l l th e m ethods s tu d ie d ,
The s iz e o f th e p ie c e a p p e ars to
make no d iffe re n c e , in th e tim e r e q u ir e d f o r b ak in g p o ta to e s
in th e c a s s e r o l e s .
The cooking p e r io d f o r th e p o ta to e s baked
w ith the s k in s on in d i r e c t oven h e a t a t 350° F . co n firm s to
recom m endations by o th e r s who have made s im ila r s t u d i e s .
The
p r e s s u r e cooking p e r io d s are v ery much s h o r te r th a n th o se
su g g e ste d in t i m e - t a b l e s .
The 2 x 2
in c h p ie c e s o f p o ta to
r e q u ir e d from th r e e to f o u r tim es as many m in u tes as th e I x l
in c h p ie c e s .
F ig u re s 8., 9 , 10, 11, 12 and 13 g iv e a g r a p h ic a l r e p r e s e n ­
t a t i o n o f th e av e ra g e h e a t flo w in cooking p o ta to e s by. th e
f o u r methods s tu d ie d .
The therm ocouple re a d in g s upon w hich
th e g rap h s a re b a se d were ta k e n e v e ry m inute d u rin g th e p r e s s ­
u re cooking and ev e ry two m in u tes during- th e b o i l i n g , s t earning
and b ak in g o f th e p o ta to e s .
F ig u re 8 shows th e h e a t flow
-31TEMR
F°
Tap w a ter without salt
20
30
Tap water with salt
40
50
60
70
TIME — M INUTF5
Curves showing th e tim e -te m p e ra tu re r e l a t i o n s h i p s
d u rin g th e b o ilin g o f p e e le d p o t a t o e s , c u t in to
p ie c e s of v a rio u s s i z e s , in tap w a te r w ith o u t and
w ith s a l t .
-32TDvff?
r°
l a p w a t e r without salt
la p w u t e r w ith S u it
W n o le p e e le d
------------
V vnoie, with s k i n s ----------
TIME: — M IN U T E S
F ig . 9 .
Curves showing the tin e - te m p e r a tu r e r e l a t i o n s h i p s
d u rin g th e b o ilin g of whole p o t a t o e s , p e e le d and
w ith s k i n s , in ta p w a te r, w ith o u t and w ith s a l t .
-3 2 TEMf?
F°
TIME — MINUTES
F ig . 10.
Curves showing th e tim e -te m p e ra tu re r e l a t i o n s h i p s
d u rin g th e steam ing of p e e le d p o t a t o e s , in p ie c e s
of d if f e r e n t s iz e .
-3 4 F°
230
210
190
170
150
I 30
I 10
90
70
J_________ I_________I_________ I_________I_________I_________L
50
10
20
30
TIME: —
11
40
50
60
70
M IN U T E S
C urves showing th e tim e -te m p e ra tu re r e l a t i o n s h i p s
d u rin g th e b ak in g of p e e le d p o ta to e s in c a s s e r o le s
-3 5 TEM R
Fa
30
TIME —
F ig . 12.
40
M IN U T E S
Curves showing th e tim e -te m p e ra tu re r e l a t i o n s h i p s
d u rin g th e b aking o f whole p o ta to e s w ith sk in s on.
-36TETMR
F°
/lO qu art P C .
/ / 18 q u a rt P C /
TIME —
F ig . 13.
/ 2 5 q u art
P C.
M IN U T E S
C urves show ing th e tim e -te m p e ra tu re r e l a t i o n s h i p s
d u rin g th e cooking of p e e le d p o ta to e s in p re s s u re
co o k ers o f t h r e e s i z e s .
-37-
• d u rin g th e b o ili n g o f p e e le d p o ta to e s o f d i f f e r e n t s i z e s .
curve f o r th e I x l
She
in c h p ie c e is much more a b r u p t th a n th e
curve f o r th e 2 x 2 in c h p ie c e and th e t o t a l tim e i s much s h o r t
e r.
Again th e a d d itio n of s a l t to th e co o k in g w a te r seemed to
cause no g r e a t d if f e r e n c e in th e c u r v e s .
I t. i s e v id e n t from
f ig u r e 9 t h a t th e h e a t flow in th e p o ta to e s b o ile d w ith s k in s
i s v ery s i m i l a r to t h a t o f th e p e e le d p o ta to e s ,
g r e a t e r la g in th e h e a t flow in th e I x l
-There i s a
in c h p ie c e s o f steam ­
ed p o ta to e s th a n in b o ile d p o ta to e s as shown b y f i g u r e 1 0 .
F ig u re 11 shows the- c u rv e s f o r th e b ak in g o f p o ta to e s in c a s s ­
e ro le s .
They a re f a i r l y s im ila r f o r th e two s ig e s o f p ie c e
b u t th e more f l a t t e n e d curve i n d i c a t e s th e lo n g e r tim e r e q u ir e d
The h e a t flo w in p o ta to e s baked in t h e i r sk in s i s g iv e n in
f ig u r e 1 2 .
The curve i s somewhat s i m i l a r to t h a t of baking
in c a s s e r o le s b u t i s s l i g h t l y s t e e p e r .
F ig u re 13 shows th e
c u rv e s f o r th e p r e s s u r e c o o k in g . o f 'p o t a t o e s ,
p ie c e , I x l
The s m a lle r
in c h , h a s th e s h a rp e r cu rv e b u t th e cu rv es f o r
th e th r e e s iz e s o f p r e s s u r e co o k er a re r a t h e r s i m i l a r .
The av erag e r e s u l t s o b ta in e d in th e cooking o f b e e ts
a re g iv e n in t a b l e I I I ;
I t . w i l l be n o tic e d t h a t a lo n g e r
cooking tim e i s " r e q u ir e d f o r b e e ts th a n f o r any o f th e o th e r
v e g e ta b le s s tu d i e d .
There i s r e l a t i v e l y v e ry l i t t l e d i f f e r ­
ence in th e amount of tim e r e q u ir e d f o r b o ili n g when s a l t i s
added to th e co o k in g w a t e r ’o r -when no s a l t i s u s e d .
Steam ing
-38-
TABIS i n . , COOKIBG DATA KOR BEETS.
Method
• . of
Cooking
C o n d itio n
of V
V eg etab le
■B o ilin g
w ith s k in s
n
Steam ing
Bakiag*
2 . Cf* 10 q t .
n
18 "
n
25 ?
TABLE IV.
H
(I
n
n
It
Tt
it
n
II
M
«
»'
4
4
4
4
I
I
I
A ? .S iz e . Av e Wt .
' P ie c e
Sample
in ;
gms.
0 ± 2 '
. 0 z 2
5 x 2-%3x2
5& x SiT
0& x 2&
3* x 3 i
554.5
626.5
590.0
5 4 6 .2
500.0
40 6 .0
491.0
A v.V ol.
Sample
OaCft
'
495
750,
, 740
627
520
080
———
Kind
of
W ater
"tap
H
M
IT
n
H
«
V o l. of Wt. o f
W ater
S a lt
CeGe , gms.
1500
1500
Air. ’Eo.
M inutes
Cooked
138
130
140
150
57
52
52
2 0 2 .8
5
1000
250
05Q
500
750
Cooking
Temp.
0F .
- » —■
202.9 2 0 2 .4
2 0 2 .4
250.0
250.0
250.0
GOOKIZG DATA EOR GKIOZS.
B o ilin g
p e e le d
U
it
Steam ing
n
it
P .C t* 10 q t .
“
18
n
25 »
TABLE, V.
, Z o.
of
T ria ls
B
It
It
4
' 4
4
4
I
I
I
x
x
x
x
B i-x
2# x
2i x
2
2
2
2
4 8 4 .5
2
2
5 l l .f i
1 #- 517.5
2 ' 496,. 2
2 ■476.0
2
504.0
506,0
2
573
610
675
■ 640
560
540
560
ta p
516.0
494.0
507.0
495.0
505.0
. 472*0
506.; 0
740
. 675
690
645
670
650
■ 710
ta p
n
, 750
750
tt
1000
it
250
050
500
' 750
n
ti
it
2 0 3 .2
5
2 0 2 .8
——
——
——
203.2
202.9
250.0
250.0 „
2 5 0 .0 .
v*e»
5
2 0 2 .8
2 0 2 .8
48
48
58
' 90
.8
8
8
CQOKIZG DATA EOR CABBAGE.
B o ilin g
q u a rte re d
a
ii
i
t
Steam ing
Ti
B aking
ii
P.C f* 10 q t .
U
R
18 n
It
it
25 n
4
2
4
4
I
I
I
* Baking i n covered, c a s s e r o le
** Steam .p re s s u re cooking
3 x 2i
0 x 2#
0 x 2-g3 X 2i
3& x 2 i
S i x 2i
3x2
it
ii
ii
it
n
it
750
750
1000
250
350
500
750
203.2
- 203.3
238.0
230; 0
230.0
*** F in is h e d co oking b e fo re re a c h in g 250° F .
See table='
r24
20
36
***
ti
n
•
—0 9 —
a p p e a rs to .req.uire ab o u t th e same amount of tim e a s b o ili n g
and th e tim e f o r b ak in g i s s l i g h t l y g r e a t e r .
A p p a re n tly ,
b e e ts can be cooked in th e p r e s s u r e cooker in about o n e - th ir d
to o n e - h a lf th e tim e r e q u ir e d f o r b o ilin g s
F ig u re s 14, 15, 16 and 17 in c lu d e th e g r a p h ic a l r e p re s e n ­
t a t i o n s o f th e h e a t flow d u rin g th e cooking of b e e t s .
F ig u re
14 shows th e, e f f e c t o f th e p re se n c e or absence o f s a l t in th e
c o o k in g 'w a te r .
From th e therm ocouple re a d in g s ta k e n ev ery
two m in u tes d u rin g th e b o i l i n g o f th e b e e ts , th e r e ap p e ars to
be v ery l i t t l e
d if f e r e n c e under ,the two c o n d itio n s .
The h e a t
flow d u rin g th e ste am in g of b e e ts is shown in f i g u r e 15 in
com parison w ith o n io n s and ca b b ag e.
The cabbage h as an ab ru p t
curve w ith a, s h o r t steam in g tim e ; th e o n io n s show some la g and
th e tim e i s In c re a s e d ; w h ile th e b e e ts have a d e c id e d la g in
h e a t flo w and th e t o t a l tim e i s much g r e a t e r th a n f o r th e o th e r
v e g e ta b le s .
F ig u re 16 p r e s e n ts a com parison o f th e h e a t flo w
fn cabbage.,- o n io n s and b e e ts d u rin g th e baking in. c a s s e r o l e s .
A ll o f th e c u rv e s a re more f l a t t e n e d th a n in any o th e r method
.of cooking and th e t o t a l tim es a r e a l l in c re a s e d o v er th o se
o f steam in g and b o i l i n g .
The p r e s s u r e cooking o f b e e ts i s
g r a p h ic a lly r e p r e s e n te d in f ig u r e 1 7 .
The s te e p e r cu rv es and.
the' h ig h e r te m p e ra tu re s re a c h e d acco u n t fo r th e s h o r t e r p e r io d
o f co o k in g tim e .
Table IV shows th e av erag e r e s u l t s o b ta in e d d u rin g th e
-40TEMP.
---------- lap w a te r w ithout sa lt
----------la p w a te r with s a lt
70
TIM E —
F ig .
14.
C urves show ing th e tim e -te m p e ra tu re
w ith o u t and w ith s a l t .
6'
M IN U T E S
re la tio n sh ip s
d u rin g
th e b o ilin g
o f w hole
b eets
in
tap
w ater
-41TEMR
E0
Onions
B e e ts
TIME
F ig .
15.
C urves show ing th e
tim e-tem perature
relatio n sh ip s
d u rin g the
steam ing o f
cabbage,
o nions
and b e e ts .
»
-4 2 TEMP
Cat bnge
Beefs
Onions
I
60
TIME —
F ig .
16.
C u rv e s s h o w in g t h e t irne-t e m p e r a t u r e r e l a t i o n s h i p s
cassero le s.
(
M IN U T E S
during
the
"baking o f c a b b a g e ,
o n io n s , and b e e t s
in
—45 —
TElMF?
r*
IOquarts R C.
/ \&quarts P C. / 2 5 quarts P. C.
60
TIME —
F ig .
17.
70
M IN U T E S
C urves show ing th e ti m e - t e m p e r a t u r e r e l a t i o n s h i p s
co o k ers o f tliree s iz e s .
d u rin g
th e
cooking of b e e ts
in p ressu re
-44-
eooklng o f o n io n s .
As compared w ith b o ilin g in ta p w ater a l o n e ,
th e a d d itio n o f s a l t to th e e pok in g w a te r a p p e a rs to make no
d if f e r e n c e i n ■th e t o t a l tim e r e p a i r e d ,
Steam ing seem s• to i n ­
c r e a s e th e tim e somewhat and b ak in g alm o st d o u b le s th e time
- r e p a ir e d .
The s iz e o f th e p r e s s u r e cooker a p p a re n tly makes
no d if f e r e n c e in th e tim e t h a t i s n e c e s s a ry f o r cooking o n io n s
a t 250° F ,
F ig u re s 15, 16, 18 and 19 p r e s e n t th e g rap h s showing the
b a tb of h e a t flo w I n ,o n io n s .
The cu rv es in f ig u r e s 15 and 16
have a lr e a d y been d is c u s s e d in com parison w ith th e coo k in g o f
b e e ts ,
F ig u re 18 shows th e s i m i l a r i t y in th e c u rv e s when s a l t
i s added to th e b o ili n g w a te r or when i t i s .O m itted .
c a s e s the. t o t a l tim e rem ain s a b o u t th e same.
In b o th
The cu rv es t h a t
a r e p r e s e n te d in f ig u r e 19 showing th e tim e and te m p e ra tu re
in co o k in g o n io n s in the th r e e s iz e s of p re s s u re co o k e rs a re
v e ry s i m i l a r , as w ould be in d ic a t e d by th e tim e s t h a t were
g iv e n in ta b le BT.
T able V g iv e s th e av erag e r e s u l t s in th e co o k in g of
cab b ag e.
There i s some evidence t h a t th e a d d itio n of s a l t
to th e cooking w a te r d e c re a s e s th e tim e r e p a ir e d f o r b o ili n g .
Steam ing a p p e a rs to r e p a i r s one an d o n e - h a lf as much tim e as:
b o i l i n g , and b ak in g r e p a i r s a tw ic e as much tim e as b o i l i n g .
Cooking cabbage in th e p r e s s u r e co o k e r r e s u l t e d in a s a t i s ­
f a c t o r y p ro d u c t when th e i n t e r n a l te m p e ra tu re o f th e co o k er
-45-
TEMP'
r°
lap w ater w ithout salt
Tap w ater with salt
j do
TllVE —
F ig .
18.
M IM U TE 5
C urves show ing th e tim e -te m p e ra tu re r e l a t i o n s h i p s
d u r i n g th e b o i l i n g o f w hole o n i o n s , i n t a p w a t e r
w ith o u t and w ith s a l t .
-46TEM R
E0
IOquarf
F ig .
19.
P. C.
/ 18 q u a r t
P. C.
TIME —
M IN U T E S
/ 2 5 q uart
P. C.
C u rv es show ing th e ti m e - t e m p e r a t u r e r e l a t i o n s h i p s
d u r i n g t h e c o o k in g o f w hole o n io n s i n p r e s s u r e
cookers o f th ree s iz e s .
reached, a p p rpximat e
230° E'.
The cabbage was v e ry much o v er­
cooked when th e te m p e ra tu re w ith in th e cooker was allow ed to
re a c h 250° F , , as recommended in some o f th e tim e t a b l e s .
F ig u re s 15, 16 , 20 and 21 a re g rap h s r e p r e s e n tin g th e
h e a t flow i n cabbage when cooked by v a rio u s m ethods.
Thermo­
cou p le re a d in g s ta k e n a t one and two m inute i n t e r v a l s were
used in p l o t t i n g th e c u rv e s .
F ig u re s 15 and 16, showing th e
c u rv e s f o r steam in g and b aking cabbage have a lr e a d y been d i s ­
c u sse d in c o n n e c tio n w ith th e ,cooking o f b e e ts and o n io n s .In f ig u r e 20 i t a p p e a rs t h a t th e a d d i tio n of s a l t to th e b o i l ­
in g w a te r made a more a b ru p t curve of h e a t flo w and .r e s u lt e d
in a s h o r te r coo k in g p e r io d th a n when no s a l t was u se d .
F ig u re
21 shows- th e h e a t flo w in cabbage d u rin g p re s s u re co o k in g .
The
v e ry a b ru p t r i s e in te m p e ra tu re e x p la in s why th e cabbage was
cooked by th e tim e th e i n t e r n a l te m p e ra tu re o f th e cooker had
re a c h e d 230P F .
D ir e c tio n s f o r th e use o f th e p re s s u re co o k er s t a t e th a t
" th e p r o c e s s in g o r cooking p e rio d b e g in s when th e in d ic a to r
on th e d i a l r e g i s t e r s th e r e q u ir e d p r e s s u r e " .
O b serv atio n s
made h e re d u rin g th e c o n tin u e d r is e , of p r e s s u r e co o k ers of
d i f f e r e n t s i z e s have le d to th e c o n c lu sio n t h a t to o l i t t l e
a t t e n t i o n i s g iv e n to th e p e rio d of tim e p re c e d in g th e cooking
p e r io d and th e e f f e c t th a t i t m ight have upon th e le n g th o f
th e cooking p e r io d ,
F o r i n s t a n c e , th e d i r e c t i o n s a g a in s t a t e
-48TE-MR
r°
Tap w a f e r without salt
la p w a te r with sa lt
no -
TIMET — MINUTES
F ig .
20.
C u rv es show ing th e
d u rin g the b o i l i n g
out and w ith s a l t .
tim e-tem p eratu re r e la tio n s h ip s
of cabbage in tap w ater w ith ­
-49-
TEMP.
F0
IO quart
PC.
I 10 quart R C.
T IM E —
F ig .
21.
2 5 q u a rt
P. C.
M IN U T E S
C u rv es show ing t h e t i r a e - te m p e r a tu r e r e l a t i o n s h i p s
d u rin g th e co oking of cabbage in p re s s u re co o k ers
of th ree siz e s.
-50-
t h a t nth e petooelc i s to he c lo s e d as soon as steam b e g in s to
issue-, from i t ,
in d ic a t in g th a t c o ld a i r has been
d r iv e n
o u t" .
A. s tu d y c a r r i e d on a t Iowa ,S ta te C o lleg e CIS) a d v is e s t h a t
steam sh o u ld be allo w ed to escap e from th e p e te o e k in a s te a d y
stre a m f o r 7 m in u tes in o rd e r to d r iv e b u t th e a i r and make i t
p o s s ib le to a t t a i n th e d e s ir e d te m p e ra tu re ;
In c o n n e c tio n
w ith t h i s p r e s e n t s tu d y , made a t an a l t i t u d e o f 5000 f e e t
above se a l e v e l , i t was found t h a t a p e rio d o f 5 m inutes o f
stream ing; steam was s u f f i c i e n t to remove th e a i r .
In o rd e r to assem ble a l l o f th e d a ta r e l a t i v e to the ex -
'
p e rim e n ts on p r e s s u r e c o o k in g , in c lu d in g , n o t o n ly th e cooking >
p e rio d s b u t a ls o a l l o f th e p r e lim in a r y p e r io d s , ta b le VI was
co m p iled .
In th e number o f m in u tes th a t e la p s e d from th e tim e
u n t i l th e steam ap p e ared and a g a in from th e c lo s in g of th e
p e te o e k 'u n t i l th e p r e s s u r e was re a c h e d , th e re a p p e a rs to be
c o n s id e r a b le v a r i a t i o n .
T his seems to- accompany th e d if f e r e n c e
in s iz e o f p r e s s u r e co o k er a s ,w e l l as th e d if f e r e n c e in s iz e
o f p ie c e ,
I t i s i n t e r e s t i n g to n o te t h a t th e c a r r o t s , p o t a t o e s ,
b e e ts and cabbage were judged a s done when cooked to an i n t e r n a l
te m p e ra tu re of 200 ° F , , w ith t h e ' e x c e p tio n o f o n io n s th a t w ere
done a t 215° F .
T ab le s V II, V I I I , IX, X and XI g iv e th,e av erag e sc o re s
t h a t were a s s ig n e d to th e c o l o r , t e x t u r e , te n d e rn e s s and f la v o r
o f th e cooked v e g e ta b le s by th e g ro u p o f ju d g e s .
The r e s u l t s
-51-
EABIiE V I.
COI'£PISTE DATA FOR STEAM PRESSURE COOKIHQ--OF THE VEGETABLES STUDIED, SHOWIHG THE MIHUTES
REQkUIRED' FOR DIFFEREHT STAGES IH THE' PROCESS AHD THE IHTERHAL TEMPERATURES
REACHED IH THE VEGETABLES.
S iz e
of
P ie c e
S ize
P ressureCooker
C a rro ts - s o r a p e l
I x l
- 1 0 %t,
I x l
18 «
I x l
25 ”
1 x 2
1 x 2
•1 x 2
2 x 2
2- x 2
2 x 2
2 x 2
Onions
2f x
2i x
Bi X
. 68
74
66 ° F .
10 a t .
60° Fv
64
58
67
57
61° F .
62
66
6 7 ° .F .
, 64
67
3 - -9 5 ° F.
3 ——99
4 — 90
5 — 180° F.
5 — 175
5 ' —160
4 f — 92° F .
5' — 156° F.
- 5 — 155
5 —155
6 — 100
8 —94
6i --2 0 9 ° F . ■;
7 — 2Q7
7 —214
3 — 231° F .
5 — 230
3 — 230
5 — 231° F .
4 — 231
- 4 —230
5 —145
5 —150
g — 75° F.
7 — 72
8 — 75
5 — 141° F . ,
5 -H O
5 — 110
3 — 174° F .
8 — 174
9 — 172
12 — 230° F .
11 —230
10 — 230
4 — 108° F .
5 --1 7 6 ° F .
5 — 180
5 — 173
4 - -2 1 3 ° - F .
6 —215
6 — 217
3 —230° F .
3 —230
3 — 230
5 — 108° F .
3 —160° F .
6 —
—160
9 — 181
12 — 230° F .
11 —230
10 — 230
3 - —60° F .
5 — 74
57 — 230° F .
52 —230
52 —230
12 - - 1 0 0
6 ——120
10 — 120
66
10 a t .
18 n
25 «
49° F .
62
62
2 -.-49° F .
3 —62
7 —65 ■
.. 5 --5 1 ° F .
5 - —64
, 5 — 74 .
10 a t .
56° F .
60
65
7 — 68 ° F .
7 — 73
10 — 80 •
65° F .
61
3 —210° F'*
6 — 213
6 —214—
M ih.
at
P re s s u r e
6 — 230° F.
5 —135° F .
“ '“6 — 113
18 "
25 n
Min. from •
C lo sin g P eteo ek
to P re s s u r e
5 --1 8 9 ° F.
9 — 198
9 — 209
10 — 72° F .
14 — 100
.
M in .o f
Steam
Escape
4 — 65° F.,
6 — 74' '
8 — 75
10 a t .
.2 x 2
B e e ts - whole
3-g- X
3* X B i
Si- x 3*
62° Po ' . '
io q.t.
18 11
25 H
18 n
2 .x 2
25 n
C a rro ts - with, sk in s
2 x 2
10 a t *
'2 x 2
18 n
2" x 2
25 "
P o ta to e s - p e e le d
I x l
10 a t .
I x l
18 »
I x l
-25 "
M in .u n til
Steam
Appears.
In itia l .
Temp.
Vegeta h le
5 ——109
8 — 100
5 —230
5 —230
- whole
2
2
2
• •
18 »
25 ' «
, 5 — 113° F .
5 — 116
5 — 115
5 —160° F .
6 —
-162
6 — 162
8 — 215° F .
8 — 215
8 — 215
TABIS T I.
S iz e
of
P ie c e
( o ont invie ± )
S ize
P re s s u re
Sqoker
In itia l
Temp.
V e g e tab le
MinA1U n til
Steam
A ppears
M in .o f
Steam
Escape
57° F .
62
60
4 — 75° F .
2 — 75
3 -.-75
5 —197° F .
5 —206
5 - —136
Min. from
C lo sin g P etco ck
to P re s s u r e
Cabbage - q u artered .
. 34- x Si■3* x Sir
3 x 2
10 q t .
18
25
"
"
3 — 230° F .
5 —230 •
8 —23Q
'
i
%
!
-53-
TABIiE V I I.
Method
of
Cooking
AVERAG-I JUBG-IEG- SGORlS ABB RESULTS OE TESTS OE COOEEB CARROTS.
C o n d itio n
• of
C a rro t
B o ilin g
it
n
tt
n
«
« **
tt it ,
it
it
it
it
Steaming.
it
tt
it
Baking***
it
P.C t***10
n
iq .
”
25
n
10
®
18
»
25
n
10
n
I8
"
25
«
. 10
n
18
H
25
sc ra p e d
it
it
it
it
tt
tt
it
w ith s k in s
n
it
n
it
it
it
sc ra p ed
it
w ith sk in s
it
it
sc ra p e d
U
it
q.ti
it
it
it
«
it
«
it
"
it
"
it
*
n
n
it
»
” w ith s k in s
if
it
n
it
it
-«
S ize
S a lt
o f , . . in
gms»
P ie c e
I x
1 x
2 x
I x
1 x
2 x
2 x
2 x
1 x
2 x
1 x
2 x
I x
2 x
1 x
2 x
I x
2 x
I x
I x
I x
1 x
1 x
1 x
2 x
2 x
2 x
2 x
2 x
2 x
l
2
2
l
2
2
2
2
2
2
2
2
l
2
2
2
l
2,
l
l
l
2
2
2
2
2
2
2
2
2
T-*
Av
.
C o lo r t T ex tu re
2 .6
4 .7
4 .1 ' 2 . 6
3 .7
4 .5
5
4 .3
3 .2
2 ,5
5
4 .3
‘ 3 .0
4 .5
5
WW
4 .3
2 .6
2 .5
5,
. 4 .6
mmmi
4 .3
2 .5
2 .5
4 .2
l i 8-5
4 .4
2 .3
5 : ' - ■ 4 .1
2 .6
4 .6
4.4*
" 2 ,4
2 .3
4 ,r
2 .9
4 .7
2.9
• 4 .3
4 .7
2 .6
'2 .5
3 .7
3 .1
4 .3
3 .2
3 .7
4 .5
2 .3
3 .6
4 .5
5 .5
3 .5 '
2 ,8
4 .4
3 .7
2il
2 .7
4 .4
2 .8
3 .8
3 .8
4 .5
3
i6
4 .1
w-w ^
' WW
WW
WW
WW
WW
WW
WW
WW
WW
WW
—T
WW
WW
WW
WW
WW
-
Av.'
P e n e tr a tio n
gms.
Judging. Scores*
T en d ern ess
E la v o r
3 .6
3 .2
3 .6
4 .4
2 .9
2 .9
2 .7
4 .0
3 .2
1 .0
2 .6
3 ,6
2 .8
3 .1
.
2 .8
2.,8
3 .2
5 .2 .
1 .9
2 .5
2 .6
2 .2
2 .7
3 ,4
2.9
2.9
4 .1
. 2 .4
2 .5 -
2 .8
2 ,1
2 ,8
4 .3 ■
4 .6
3 .2
3 .3
3 .6
1 ,8
2 .6
2 .7
3,1'
2 .5 '
3 .1
1 ,7
3 .1
2 .2
2 .6
2.9
2 .2
2A1
3;3
3 ,2
1 .3
2 .7
2 .4
' 2 .7
1 .6
2 .2
1 .3
2 .6
-
Av.pH Value
Cooking
liq u id
7 .0
. 7 .0
7 .0
7 .0
7 .0
7 .0
Si 8
5 .8
7 ,0
7 .0
6 . 8:
7 .0
7; 8
,7 .8
7 .8
7.8
5 .8
5 .9
3.9.1 ‘
433
288
285
354
236
366
305
369
279
321
288
319
390
438
247
313
374
205
141
132
157
138
192
123
87'
w —W
7 .0
7 .0
6 ,5
6 .1
WWW,
6 .4
6 .1
121
—
168
109
119
6 ,8
6 .1
6 .8
■
'
* System u se d in s e a rin g v e g e ta b le s :0 - v e ry poor
1 s. poor
2 - fa ir
3 - medium
4 :: good
5 = e x c e lle n t
** B i s t i l l e d wateib.
*** Baking in co v ered c a s s e r o le
**** Steam p r e s s u r e cooking
.
,.
-
:
-54-
TABLE V I I I .
AVERAGE JUDGIHG SOORES AZD RESULT^ OF TESTS OH OOOEED POTATOES,
Method
of
Cooking
C o n d itio n
of .
P o ta to
B o ilin g
p e e le d
Il
«
It
H
n
n
T!
it
tt
Tl
TT
Steam ing
Tl
Baking**
Tl
Tl
P . G
t * *
10
"
18.
25
n
10
"
"
"
18
25
S ize
S a lt
OX
i n
P iec e
gms.
I x l
2 x 2
I x l
2 x 2
— —-
5
5
Si
w ith s k in s 3*
p e e le d
3i
w ith s k in s s i
p e e le d
I
——
x li
— •*
X Ii
x Ii - 5
x ii
5
— —
x l
. n
——
2 x 2
n
*- —
I x l
n
2 x 2
— ww ith s k in s S i x 2
—W
q tJ p e e le d
I x l
it
«
I x l
-•n
M
------ '
"
I x l
U
—w
"
2 x 2
R
——
»
2 x 2
n
”
—
—
2 x 2
System, used, in s c o rin g v e g e ta b le s :^
0 = v ery poor
1 = poor
2 = fa ir
3 ' s- medium
4 s gopd
5 = e x c e lle n t
„AvV Judg in g S cores*
C olor
-Texture
3 .5
4 .0
3 .5 '
4 .3
3 .0
4 .5
4 .5
3 .3
3 .3
4 .2
4 i2
0 .2 :
3 .4 ... 4 .5
■3 .1
4 .5
4 .0
2 .8
4 .0
410
3.7
4 .0 '
4 .4 '
‘ 3 .4
2 .9
4 .6
4 .0
4 .5
4 ;0 ‘ - 4 .6
4 .0
4 .,6
3 .0
" '4 . 5
4 .5 '
3 .0
3 .0
4 .5
"
T enderness
• /
4 .0
3 .8
3 .6
4 .3
4 .2
'3.5
4.6
- 4 .8
3 .1
3 .9
3 .5
0 .9
3 .5
4 .0
3 .3
2 .6
2 .0 '
2 .0
3 .5
F la v o r
2 .8
, 2 .6
3 ,8
2 .5
4 ,0
3 .8
4 .0
4 .3
3 .0
3 .5
3 .4 3 .6
3 .0
4 .0
2 .6
2 .3
1 .0
1 .0
1 ,0
Av.
P e n e tr a tio n
gms.
139
104
149 ■
154 .
108
147
103
146
136
101
211
166
95
8S .
129
106
126
141
129
Baking in co v ered c a s s e r o le
* * * ’Steam p r e s s u r e cooking
Av.pH- Value
Cooking
liq u id
6 .5
6 :4
6 .2
6 .5
7 .0
6 ,9
7 ,0
7 ,0
7.0
6 .6
6 ,0
6 .0 .
■ • W
6 .7
6 .8
6 .8
6 :8
7 .0
6 .9
TABIS I X .
AVERAGE JU D G H G SCORES AID RESULTS OF TESTS O I COOKED BEETS.
- Me tn Od..
of
Cooking .
C o n d itio n
of
V egetable
S ize
of
P iec e
B o ilin g
w ith s k in s 3 x 2
n
n
it
3x2
it
ii
Steam ing
3 x 2-gn
it
Baking**
8 z 2 :H
1
1
2 . Ct** 10 CLt;'
3|r x 3^n
ii
«
18 "
8 & Z 2&
It
H S i x Bi
"
25 H
TABLE X,
C olor
4 ,3
4 .5
4 /5
4 :4
4*0
5*0
3 .0
5
we*
WW
WW
WW
T ex tu re . T enderness
3.3
3 .5
2:7
3 .4 3 :3
0;S
3 .0
4 .1
4 .2
5 .8 ,
5 .4
4 .0 .
5 .8
4 .0
■ , ' ' Av.
P e n e tr a tio n
F la v o r
gms.
4 .2
'4 .2
3 :5
. 3 ;5
4 ,3
. 3 .8
4; 0
"
" 386
404
410
391
258
415
Av'. pH Value
Gookihg
liq u id
W■»
WWW
WWW
WWW.
—
221
AVERAGE JUDGIIG SCORES AID RESULTS OF TESTS OI COOKED O IIO IS. ■
B o ilin g
n
Steam ing
Baking^*
P.C t** 10 q t.
n
ps n.
”
25 n
, TABLE' X I.
Avo Ju dging S cores*
S a lt
in
gms.
p e e le d
Tl
Il
It
n
n
«
x
x
x
■
x
IBi x
Bi x
Bi x
2
2
2
2
2
2
Ii
2
2
2
2
4 :3
3*8
4 .0
3 .7
WW
■ 5
—f"
WW
1 .0
1*0
W—
WW
4 ,0
WW
3.9
5 .9
2 .0
2 .7
3 :0
3 .0
3 .0
.
4 :4
4 :3
4 ,0
1.9
4 :8
4 .5
' 4 .0
1 .0
1 .0
. 0 .0
' 0 .0
5 .0
0 .0
•
WWW1
6 .0
-5.8
WWW
6 .8
2 .8
-5:3
5 .4
5 .8
WWW
WWW
6 :0
AVERAGE JUDGIIG SCORES AID RESULTS OF TESTS Ol COOKED CABBAGE.
' - B o ilin g
it
- Steam ing
Baking**
P .C t** 10 .qt«
"
18 »
"
25 n
q u a rte r ed
n
Tl
It
Tl
It
n
5
5
5
3
si
si
3
x
x
x
x
Bi
Bi
Bi
Bi
x
Bf
x Bi
x2
Ww-
5
WWWW WW
WW
WW
* System used, in s c o rin g v e g e ta b le s :O s v e ry poor
. I s poor
2 r fa ir
S = medium
4 ■= good.
5 s e x c e lle n t
^
3*0
3 .0
3 .0
4 .0
3. 0
4*0
. 3 .0
3 :8
4 .0
3 .0
3 .2
3 ,0
3 .0
3, 0
4 .8
4 .6
4 .3
3 .6
3 .5
4*0
4 .0
4 .2
5 .0
2 .;0
3 .3
3 .5
3 ,0
3 ,0
"6.4
6 ,3
7 .0
WWW
WWW
a
WWW
WWW
WWW
WWW
WWW
WWw
_
_** B aking in covered, c a s s e r o le
*** Steam p r e s s u re cooking
7 .0
7.0
7.0
-56-
o f th e p e n e tr a tio n t e s t s f o r te n d e rn e s s a re a ls o found in
th e s e t a b l e s in o rd e r t h a t th e y m ight be compared w ith th e
ju d g es * o p in io n s o f te n d e r n e s s , Ho p e n e tr a tio n t e s t s were
made on o n io n s o r cabbage because o f t h e i r s t r u c t u r e .
The
av erag e hydrogen io n c o n c e n tr a tio n o f th e cooking l i q u i d s
a s e x p re s se d in pH v a lu e i s l i s t e d h e re f o r a l l e a s e s where
i t was p o s s ib le to make th e t e s t s c o lo r im e tr ic a lly *
I t w i l l be se en in ta b l e Y II t h a t th e pH v a lu e of th e
cooking l i q u i d when c a r r o t s were b o ile d in ta p w a te r was
u s u a l l y 7 .0 b u t when th e y were baked in ta p w a te r t h i s v alu e
f e l l to 5*8 w hich was s im ila r to th a t of th e d i s t i l l e d w ate r
in w hich c a r r o t s were b o ile d .
The pH v alu e of th e l i q u i d
a f t e r th e p r e s s u r e co o k in g o f c a r r o t s seems to in d ic a te g r e a t ­
e r a c i d i t y th a n a f t e r b o i l i n g or .steam in g .
A ll o f th e pH
v a lu e s f o r th e l i q u i d u sed in coo k in g onions were n o tic e a b ly
low er th a n th e pH o f th e ta p w a te r i t s e l f v
In th e cooking o f
cabbage th e pH v a lu e s were lo w e r f o r th e l i q u i d from b o ilin g
th a n from steam ing and p r e s s u r e co o k in g .
-57-
DISCUSSIOE
From th e d a ta p r e s e n te d in th e p re c e d in g ta b le s and
g r a p h s , i t i s a p p a re n t t h a t c e r t a i n f a c t o r s are in v o lv e d in
th e r e l a t i o n s h i p betw een th e tim e r e q u ir e d f o r cooking vege­
ta b l e s and th e te m p e ra tu re a t w hich th ey a r e cooked.
P erh ap s one o f the most o u ts ta n d in g f a c t o r s in t h i s r e ­
l a t i o n s h i p i s th e s iz e o f th e p ie c e of v e g e ta b le to be cooked.
I t h as b een c o n s i s t e n t l y o b serv ed in t h i s s tu d y t h a t when la r g e
and sm a ll p ie c e s o f th e same v e g e ta b le were cooked a t the same
te m p e r a tu r e , th e la r g e r p ie c e alw ays r e q u ir e d a lo n g e r cooking
p e r io d ,
T his i s p ro b a b ly due to th e g r e a t e r d is ta n c e th ro u g h
w hich th e h e a t must flo w in o rd e r to re a c h th e c e n te r of th e
l a r g e r p ie c e .
However, i t i s i n t e r e s t i n g to n o te th a t th e
d i f f e r e n t tim es r e q u ir e d f o r h e a t p e n e tr a tio n in to d i f f e r e n t ­
s iz e d p ie c e s of th e same v e g e ta b le a r e 'n o t alw ays in d ire c t,
■
p r o p o r tio n to th e s e s i z e s , th a t i s , i t does not. u s u a lly ta k e
e x a c tly tw ice a s much tfm e f o r h e a t to re a c h th e c e n te r o f a
2 x B in c h p ie c e a s a I x I in c h p i e c e .
T h is a p p e a rs to v a ry
w ith th e te x tu r e and s t r u c t u r e o f th e v e g e ta b le s .
W hile ca n n in g o f v e g e ta b le s i s a p ro c e s s somewhat d i f f e r ­
e n t f r o m .t h e ir d ire c t: co o k in g , i t sh o u ld be n o te d t h a t , in
c a n n in g , th e s iz e o f th e can i s a f a c t o r th a t h a s been c o n s id ­
e re d in d e te rm in in g th e tim e o f th e p ro c e s s in g p e r io d .
Bigelow ( I ) , o f th e N a tio n a l G an n ers1 A s s o c ia tio n , s t a t e s
-58-
11th e tim e n e o e s s a ry f o r h e a t to p e n e tr a te to th e c e n te r of
cans o f d i f f e r e n t s iz e i s ap p ro x im a tely p ro p e rtio n a .1 to th e
sq u a re of th e r a d i i o f th e cans .•
I t sh o u ld "be u n d e rsto o d t h a t
t h i s r e f e r s o n ly to th e tim e n e c e s s a r y to b r in g th e c e n te r o f
th e c a n s to s p e c i f i e d t e m p e r a t u r e s . Magoon and C ulpepper (12)
conclude t h a t th e d if f e r e n c e s in th e d ia m e te r o f th e c o n ta in ­
e r s a r e o f much l e s s im p o rtan ce in th o se m a te r ia ls in' w hich
th e r e i s a f r e e l i q u i d th a n in m a te r ia ls o f heavy c o n s is te n c y ,
so th e r e i s l i t t l e
d if f e r e n c e in th e p ro c e s s in g p e rio d of
Ho. 2 and Ho. 2 t i n can s of s t r i n g beans., b u t th e r e i s con­
s id e r a b le d if f e r e n c e in th e p ro c e s s in g p e rio d o f Ho.. 2 and
Ho.■ 2 t i n cans o f sw eet co rn .
S e d f i e l d , H elson and S u n d e rlin
(15) a t Iowa S ta te C o lleg e recommend a d d i tio n a l tim es f o r
p r o c e s s in g q u a rt j a r s over th e tim es re q u ir e d f o r p in t j a r s .
Ih e only w orker who has u se d d e f i n i t e s i z e s o f v e g e ta b le
p ie c e s i n d e te rm in in g t h e i r cooking tim e a t a c e r t a i n tem pera­
t u r e is G -ill ( ? )
and h e r work was lim ite d to p o ta to e s ;
How-,
e v e r , h e r r e s u l t s c o in c id e w ith th e r e s u l t s found in t h i s ,
s tu d y .
A la c k o f r e c o g n itio n o f th e e f f e c t o f s iz e o f p ie c e
upon th e le n g th o f th e cooking p e r io d f o r v e g e ta b le s p ro b a b ly
.accounts f o r th e wide range o f tim e g iv e n in tim e - ta b le s
w hich have been p r e s e n te d by a number o f th e w orkers*
A nother f a c t o r t h a t seems to have r e c e iv e d l i t t l e
a tte n ­
t i o n i s th e i n t e r n a l te m p e ra tu re o f th e v e g e ta b le t h a t sh o u ld
-59-
Iae reac h ed when i t i s cooked. - D enton ( 5 ) i n 1922 s t a t e d t h a t
nW ith th e e x c e p tio n o f m e a t, eggs and c u s ta r d s , m ost foods
cooked under o rd in a ry h o u seh o ld c o n d itio n s r e a c h a te m p e ra tu re
o f a p p ro x im a te ly IOO0 ( b o ilin g p o in t) th ro u g h o u t t h e i r mass
by th e tim e th e y a r e Edonetr, w hether cooked in b o ili n g w a te r,
tn an oven, o r in h o t f a t a t 200° C ;, more or l e s s .
However,
i t may r e a d i l y be shown t h a t th e te m p e ra tu re a t t a i n e d w ith in
a g iv e n tim e p e r io d i s a l t o g e t h e r dependent upon th e s iz e o f
th e food m ass 4
B b ilp d p o ta to e s w eighing 200 grams o r l e s s , a re
done a t 9 ? ° -9 9 0 C ,, th o se w eig h in g 300 grams o r more *.'are done .
a t 9 0 °-9 5 0 0-.,r
In t h i s s tu d y , co n d u cted a t an a l t i t u d e pf
5000 f e e t , where th e b o ili n g p o in t o f w a te r v a r ie s from 9 4 .5 °
to 9 5 .5 ° 0 . , o r 20B° to 204° 3?',, th e v e g e ta b le s cooked by
b o i l i n g , steam in g and bak in g alw ays re a c h e d an i n t e r n a l tem­
p e r a tu r e com parable to th e b o ili n g p o in t of w a te r , re g a rd le ssof t h e i r s iz e .
In a d d i tio n , i t was alw ays n e c e s s a r y to h o ld
them a t t h i s i n t e r n a l te m p e ra tu re f o r a c e r t a i n , p e r i o d o f
tim e b e fo re th e y were done.
T h is w i l l be seen in th e l a s t
p o r t i o n .o f eanh cu rv e in th e g r a p h s A re c e n t s tu d y r e p o r te d
in 1933 by S to u t and D ro ste n (18) bn th e h e a t flo w th ro u g h
b a k e ry p r o d u c ts , shows a s i m i l a r c o n d itio n t h a t e x i s t s during,
th e bakin g of b re a d .
They s t a t e t h a t when oven te m p e ra tu re s
v a r ie d from 200° to 2£0° C, th e in s id e te m p e ra tu re of a lo a f
Of
b read d id n o t exceed IOO0 to IQ l0 0« d u r in g b a k in g 4 This
-60-
te m p e ra tu re had to be m a in ta in e d f o r d t l e a s t a p e rio d o f
9 m in u tes t o produce a done l o a f o f b re a d .
D uring th e p r e s s u r e cooking o f v e g e ta b le s a t 2500 F.
o r 15 pounds p r e s s u r e ( c o r r e c te d f o r th is a l t i t u d e ) , th ey
alw ays seemed to>, be "done" when th e i n t e r n a l te m p e ra tu re o f
th e v e g e ta b le re a c h e d 230° F f
T h is a p p a re n tly was th e c o r r e c t
i n t e r n a l te m p e ra tu re f o r a l l v e g e ta b le s t e s t e d , r e g a r d le s s of
s iz e .
A nother qu estio n , t h a t e n te r s in to t h i s problem o f vege­
ta b l e co o k ery i s w h eth er th e a d d i tio n of s a l t to th e w ater
makes any d i f f e r e n c e . i n th e t o t a l tim e r e q u ir e d f o r b o ilin g
v e g e ta b le s .
P re lim in a r y to t h i s s tu d y a t e s t was made by
ad d in g 5 grams o f s a l t tO' 750 e e . o f ta p w a te r, a llo w in g i t
to b o i l and com paring' i t s b o ilin g te m p e ra tu re w ith th a t o f
an e q u iv a le n t amount of w a te r h a v in g no s a l t .
There was ho
in c r e a s e in te m p e r a tu r e , ac c o rd in g to a m ercury th erm o m eter,
when s a l t was p r e s e n t f
An ex a m in a tio n o f the d a ta and graphs
w i l l a l s o show t h a t th e r e was p r a c t i c a l l y no d if f e r e n c e in
th e tim e or te m p e ra tu re fo r cooking v e g e ta b le s , w h eth er s a l t
was p r e s e n t pr' a b s e n t•
f in d in g s o f o th e r s .
T his seems to be c o n s is te n t with- th e
Magoon and C ulpepper (12) s t a t e t n a t
"sodium c h lo r id e has v ery l i t t l e
d i r e c t e f f e c t upon th e r a t e
o f change o f te m p e ra tu re in th e c a n ,- d u r in g c a n n in g ."
S t i l l a n o th e r m 'atte^to be c o n s id e re d in th e c o Okepy of
-
-61-
v e g e ta isle s i s w h eth er th e p re se n c e o r absence o f t h e i r s k i n s ,
lu r i n g th e cooking p r o c e s s , h as any e f f e c t on t h e i r r a t e of
co o k in g .
P o ta to e s and. c a r r o t s were used., f o r th e s e t e s t s and.
th e r e s u l t s in d ic a te t h a t th e p resen ce, o f s k in s on th e c a r r o t s
may r e t a r d th e r a t e o f h e a t flo w , b u t th e s k in s on th e p o ta to e s
seemed to cau se a s l i g h t in c re a s e in th e r a t e o f h e a t flow as
compared w ith p e e le d p o ta to e s .
T his d if f e r e n c e m ight be a t t r i x'
.
b u te d to th e f a c t th a t th e p ie c e s o f c a r r o t were c u t a t b o th
ends in o rd e r to o b ta in a 2 x 2 in c h p ie c e w h ile th e p o ta to e s
were cooked w hole and had no o u t s u r f a c e s ,
W hether i t i s a
d if f e r e n c e betw een c u t s k in or i n t a c t s k in , o r in te x tu r e of
s k in , h as n o t been d eterm in ed ;
In making a com parison of th e f o u r methods o f cooking
t h a t were u sed in t h i s stu d y i t was n o tic e d t h a t th e re seemed
to be a d if f e r e n c e in th e r a t e a t w hich each k in d o f h e a t,
depending upon i t s s o u rc e , p e n e tr a te d th e v e g e ta b le s .
Steam
p r e s s u r e co o k in g alw ays r e q u ir e d th e l e a s t amount o f tim e to
cook th e v e g e t a b l e s .
B o ilin g came n e x t in tim e r e q u ir e d ;
steam in g n ex t.» and b ak in g was th e slo w e st p r o c e s s .
ih is is
p a r t i c u l a r l y i n t e r e s t i n g when th e I r .re s p e c tiv e te m p e ra tu re s
a re n o t e d : - steam p r e s s u r e co o k in g , 250° P .; b o i l i n g 202° TV,
ste am in g , 202° to 204° P .; and b a k in g , 350° P .
I t would
seem t h a t th e re must be some d if f e r e n c e in th e q u a l i t y or
q u a n tity of en erg y d e riv e d from each o f th e s e f o u r media th a t
I
-62-
"bring th e h e a t to th e v e g e ta b le , p a r t i c u l a r l y th e . l a t t e r ; ■
In c o n s id e r in g th e d i f f e r e n t v e g e ta b le s i t was found
t h a t th e y v a r ie d in th e r a t e a t w hich th e y cooked.
T h is ,
d o u b tle s s , i s caused by u n lik e s t r u c t u r e s found in th e ty p e s
o f v e g e ta b le s u sed .:- p o ta to e s a re tu b e r s o r u n d erground stem s;
c a r r o t s and b e e ts a re r o o t s ; onions, a re b u lb s ; and cabbage i s
a com pact.head form ed o f le a v e s .
I t i s a ls o re c o g n iz e d t h a t
th e m a tu rity o f v e g e ta b le s may have seme e f f e c t on t h e i r cook­
ing r a t e . • In t h i s stu d y the v e g e ta b le s were p r a c t i c a l l y u n i­
form in t h e i r d eg ree o f m a tu rity a s they had been s to r e d in
p i t s f o r th r e e to f o u r months*
In stu d y in g th e g ra p h s t h a t r e p r e s e n t th e tim e -te m p e ra tu re
r e l a t i o n s h i p s d u rin g th e b o ilin g ,, steam in g and b ak in g of vege­
ta b l e s i t w i l l be seen th a t th e y may be d iv id e d in to th r e e
d i s t i n c t p e r io d s .
The f i r s t p e r io d c o n s is ts o f a p a p id r i s e
o f te m p e ra tu re w ith in ;.th e v e g e ta b le , in d ic a te d on th e -g ra p h
by th e f i r s t , s te e p p o r tio n .
The second p e rio d i s one o f
p r o g re s s iv e d e c re a se in th e r a t e o f te m p e ra tu re r i s e , w hich '
r e s u l t s in t h e ■curved p a r t o f th e graph*
The t h i r d or f i n a l
p e r io d i s one o f c o n s ta n t te m p e ra tu re where th e c e n te r o f th e
v e g e ta b le h as a t t a i n e d th e te m p e ra tu re of b o i l i n g w a te r,
fhe
le n g th of ■th e t h i r d p e r io d varies" w ith d i f f e r e n t v e g e ta b le s
and w ith d i f f e r e n t methods o f c o o k in g .
In th e g ra p h s r e p r e ­
s e n tin g p re s s u re ; c-Odking th e se p e r io d s a re n o t a p p a re n t.
-63-
In a d d i tio n to th e f a c t o r s w hich have- j u s t been d is c u s s e d
th e r e are some o b s e rv a tio n s w hich are i n t e r e s t i n g t o ’ n o te .
From th e t e s t s f o r te n d e rn e s s t h a t were made w ith th e penom d te r, i t was e v id e n t th a t d i f f e r e n t w eig h ts were n e c e s s a ry
to p e n e tr a te d i f f e r e n t k in d s o f v e g e ta b le s , even though th e y
w ere a l l sc o re d as "done" by th e ju d g e s .
T his in d ic a te s t h a t
our id e a s ab o u t th e q u a l i t i e s t h a t mark th e "doneriess" o f
v e g e ta b le s v a ry w ith each v e g e ta b le , '■
' .
, ■
A nother o b s e rv a tio n t h a t seems to be r e l a t e d to th e tim e
and te m p e ra tu re r e q u ir e d f o r coo k in g v e g e ta b le s i s th e h y d ro ­
g e n -io n c o n c e n tr a tio n o f th e w a te r in w hich th e y were cooked.
T h is s tu d y a p p e a rs to show a g r e a t e r a c i d i t y o f th e l i q u i d
a f t e r p r e s s u r e co o k in g and b ak in g in c a s s e r o le s th a n in th e
o th e r m eth o d s, when e x p re sse d in pH v a lu e s . . I t may. be p o s s ib le
t h a t th e h ig h te m p e ra tu re in p r e s s u r e cooking and th e lo n g
p e r io d in b ak in g have te n d e n c ie s to cause a ch em ical change
in th e v e g e ta b le w ith a r e s u l t i n g in c re a s e in a c i d i t y .
-64—
SUMMARY
I.
In t h i s s tu d y of th e tim e -te m p e ra tu re r e l a t i o n s h i p s in
th e co o k e ry o f v e g e ta b le s , th e fo llo w in g v e g e ta b le s were
u s e d :- c a r r o t s , p o ta to e s , b e e t s , o n io n s ' and cab b ag e.
So
These v e g e ta b le s were cooked b y .b o ili n g , ste a m in g , d i r e c t
b a k in g , b a k in g in c a s s e r o le s and by steam p r e s s u r e co o k in g .
3.
The co o k in g t e s t s , ,t h a t f u r n is h e d th e d a ta f o r t h i s stu d y ,
were c a rrie d , on a t an a l t i t u d e o f ab o u t 5000 f e e t above
se a l e v e l , where th e te m p e ra tu re o f b o ilin g w a te r v a r ie s
from SOS0 to SO4° R.
4.
T herm ocouples, w ith t h e i r h o t- e n d ju n c tio n s i n s e r t e d in to
th e e x a c t c e n te r o f each p ie c e of v e g e ta b le t e s t e d , i n d i ­
c a te d th e te m p e ra tu re w ith in th e v e g e ta b le a t d e f i n i t e
tim e i n t e r v a l s .
5.
From th e d a ta p r e s e n te d , i t i s a p p a re n t t h a t c e r t a i n f a c t o r s
a re in v o lv e d in th e r e l a t i o n s h i p between th e tim e r e q u ir e d
f o r cooking v e g e ta b le s and th e te m p e ra tu re a t w hich th e y
a re cooked.
6.
One of th e most im p o rta n t f a c t o r s i s th e s i z e o f the p ie c e
o f v e g e ta b le ,
A la r g e p ie c e r e q u i r e s a lo n g e r cooking
p e r io d th a n a sm a ll p ie c e , even though th e tim e i s n o t in
d i r e c t p r o p o rtio n to, th e s i z e .
7.
In b o i l i n g , steam ing and b ak in g v e g e ta b le s , i t is n e c e s s a ry
-65-
f Or’ th e c e n te r o f th e p ie c e to r e a c h th e "boiling p o in t
o f w ate r and m a in ta in t h a t te m p e ra tu re f o r a c e r t a i n
p e r io d o f tim e , depending on th e k in d o f v e g e ta b le and
method o f c o o k in g .
Si
D uring th e p r e s s u re coo k in g o f th e s e v e g e ta b le s a t 25Q9 F .
o r 15 pounds p r e s s u r e ( e o r r e b te d f o r an a l t i t u d e of 5000
f e e t ) th e y were done when th e i n t e r n a l te m p e ra tu re of th e
v e g e ta b le re a c h e d 280° F,"
In th e case o f cabbage t h i s
te m p e ra tu re was re a c h e d b e fo re th e te m p e ra tu re in th e '
p r e s s u r e co o k er was 250° F.
9.
$he a d d i tio n o f s a l t to th e w a te r when b o ilin g v e g e ta b le s
d id n o t ap p ear to make any d if f e r e n c e in th e b o i l i n g temp­
e r a t u r e o f th e c o o k in g .liq u id , n o r in th e t o t a l tim e r e ­
q u ire d f o r co o k in g .
10.
When p ie c e s o f c a r r o t were p re p a re d fo r co o k in g b y c u ttin g
o f f th e ends b u t le a v in g th e s k in s e n c i r c l i n g 't h e c a r r o t ,
th e h e a t flo w in to th e p ie c e o f v e g e ta b le was r e ta r d e d .
When p o ta to e s w ere cooked w ith th e s k in s l e f t on i n t a c t
th e r e seemed t c be a s l i g h t in c r e a s e in th e r a t e of h e a t
flo w a s compared w ith p e e le d p o ta to e s .
Ilf
In making a com parison of th e f o u r methods of cooking i t
was n o te d t h a t th e r e seemed to be a d if f e r e n c e in th e
r a t e a t w hich th e h e a t in each method p e n e tr a te d th e vege­
ta b le s *
Steam p r e s s u r e co o k in g alw ays r e q u ir e d th e l e a s t
-66-
amount o f tim e to oook th e v e g e ta b l e s ;r h q il lh g came n e x t;
^team ing n e x t; and b aking was th e slo w e st p ro c e ss*
12.
These v e g e ta b le s d i f f e r e d in th e r a t e . a t w hich th e y cooked,
d o u b tle s s due to a d if f e r e n c e in t h e i r s t r u c t u r e .
115.
Graphs r e p r e s e n tin g th e tim e -te m p e ra tu re r e l a t i o n s h i p s
d u rin g th e b o i l i n g , steam in g and b ak in g o f v e g e ta b le s may
be d iv id e d in to th r e e d i s t i n c t 'p e r i o d s . ' The f i r s t i s s te e p ,
i n d ic a t in g a r a p id r i s e in te m p e ra tu re ; th e second i s c u rv ­
ed , showing a d e c re a s in g r a t e of r i s e ; th e t h i r d i s h o r i ­
z o n ta l, show ing m aintenance o f c o n s ta n t te m p e ra tu re .
M1
Penom eter t e s t s o f cooked v e g e ta b le s, show t h a t th e term
"d o n e n ess” . does n o t mean t h a t th e y a l l have th e same d eg ree
o f p e n e tr a tio n .
15.
The h ig h e r a c i d i t y of th e l i q u i d from p re s s u re cooked and
c a s s e ro le -b a k e d v e g e ta b le s s u g g e s ts th a t some ch em ical
change h as o c c u rre d d u rin g th e s e cooking p r o c e s s e s .
-67-
ooiaLus loirs
1.
T.he tim e r e q u ir e d to cook a v e g e ta b le depends on th e
r a t e a t w hich h e a t p e n e tr a te s to i t s c e n te r an d p roduces
a d e s ir a b le d eg ree o f te n d e r n e s s , !mown as " d o n e n e s s " .
2.
In com paring' th e -four methods o f cooking u sed in t h i s
s tu d y , steam p r e s s u r e , w ith i t s h ig h e r te m p e ra tu re ,
cau sed a more r a p id r a t e of h e a t p e n e tr a tio n and th u s r e ­
q u ire d th e l e a s t amount o f tim e f o r cooking th e v e g e ta b le s .
B o ilin g came n e x t in tim e r e q u ir e d ; steam in g , n e x tt and
bak in g was th e slo w e st p r o c e s s .
3.
W ith th e e x c e p tio n o f steam p r e s s u r e cooking th e r a t e o f
h e a t p e n e tr a tio n in to th e v e g e ta b le s f a l l s ' in to th r e e
p e r io d s .
In th e f i r s t , th e r e i s a r a p id r i s e in tem pera­
t u r e ; in th e seco n d , a slow er r a t e o f in c re a s e in tem pera­
t u r e ; and in th e t h i r d , m aintenance o f a c o n s ta n t tem pera­
tu re .
4.
The s iz e o f th e p ie c e of v e g e ta b le to be cooked a f f e c t s
th e tim e r e q u ir e d f o r th e p e n e tr a tio n o f h e a t ;
The la r g e
e r th e p ie c e th e lo n g e r th e tim e t h a t i s r e q u ir e d f o r
co o k in g .
5.
In b o i l i n g , th e a d d i tio n of s a l t to th e cooking l i q u i d
does n o t a p p r e c ia b ly r a i s e i t s b o ilin g te m p e ra tu re n o r
does i t ap p ear to a ffe & t th e tim e r e q u ir e d f o r cooking
v e g e ta b le s .
—68 —
ACHffOWIiEDG-MEisriS
■The w r i t e r w ish e s to e x p re s s h e r a p p r e c i a t i o n ■f o r th e
a s s is ta n c e and g u id a n ce g iv e n h e r d u rin g t h i s s tu d y by
D octor J e s s ie E. R ic h a rd so n and M rs. H elen L.- M a y fie ld , o f
th e D epartm ent o f Home' Economies o f th e Montana E xperim ent
S ta ti o n ; and to e x te n d h e r th a n k s to th e judging, com m ittee.
-69-
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■■ .
■
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"V
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■ •'
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!
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■
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