’3'23

"55
3‘15

4M."
5

:“é a
ham:
‘3: T -

J

M: am.
aim n... o

4"“. I *~ c .. 3‘.- h

0.4 J In} \

.4.‘ .V‘ ‘\ .m- 3 -.
”NH.” 00L. . J . i .31-
.1. . a L ...
$0.1,“ '1?‘ a! :“d‘ Q‘U

i
3
3*
it ,
R

u A ... .... .. .
{L “1‘ I "QM.- - ‘ ‘v! J.“ I I...
h .‘u u. . an“. ..w ..J iw
.9D0\ ‘1 Or: ,A C. «V5 V
a! r a «I "
0C.“ U‘\h.§‘ Q. o :2... ....
. . ‘u ‘0 ‘ " “ K! In ‘0 u
.k ....h... k .8. NW u. .
$I't. l“ "v . Mug 1 y
| ,3. I I
., w .-. i an . a ..x. . L
:33 I s :1. ..- L .
h. 5 W‘ . u k. ....w n ...w a...»
I gr. "3 . . NIHM h .\. ...... ’;
3;. 3 1 - . .. - .. y

64
{I
D

l

«A.
c o.
.

‘ l:
L
1‘.
‘

'
a ‘
I I. k

£7. {a a & .... Am“ J ..
.r‘w d It; 11‘ .(IL. ..MVJ
.- ‘ "i ‘1“ l‘ .l 1‘ .
1.. .41 . wt. 4.. ..n... .- .
.u . ,vd ..nu ....“ aim

in

8

1 t

1 . #-

tc‘t‘u’i
S.
K
.I

§

3

‘

(a

\u
{*3 :5

if}? 5-
: “g
L: H.)

I
3. ”h‘
I
E
4“-
\J

I ....ll 64... ... u
...“..o L I ~.-- by“
an 4.. L?"-
01'...
~ . a a
g . .-.
‘l .P‘ u
’6‘“ .4‘ a
!
. ... . u I
n ‘1.
... a: ...
I: L
99.... 16...“
.3.“
In. an.“
4‘ IR.“
ant.
.w L

._ . - L. I...‘ - 11,.
k

  

PLACE ll RETURN BOXtonmovombclnckomm ywrrocord.
To AVOID FINES Mum on or baton duo duo.

DATE Dig; DATE DUE DATE DUE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

‘4 ‘— ——— _
j

MSU Is An Afflnndivo Amen/Equal Oppommy Institution
WM:

 

_. ,__’_——_..

Hmwv

 

 

 

 

The put;
calzi'm cycl:
gelatin and ‘

The has:
Meats ex:
the gaming J

in milk-type

 

ABSTRACT

THE EFFECT OF SUCROSE AND CALCIUM CYCLAHATE
UPON THE GEL STRENGTH OF SELECTED GELLING AGENTS
IN THE PREPARATION OF JELLIED CUSTARD

by Mary Ellen Zabik

The purpose of this study was to compare the effects of sucrose and
calcium cyclamate upon the gel strength of jellied custards prepared with
gelatin and two marine hydrocolloids, carrageenan and algin. A

The basic formula consisted of constant proportions of all in-
gredients except the gelling and sweetening agents. Representatives of
the gelling agents, chosen arbitrarily from products recommended for use
in milk-type dessert gels, were pure, unflavored, acid—processed gelatin
with a bloom value of 220; carrageenan;1 and algin preparation2 which
were added in the predetermined gram-ratio of 1.00 : 0.179 : 0.857,
respectively. Custards gelled with each agent were sweetened by the
following 5 methods: with 20 and #0 per cent sucrose, based on total
formula weight exclusive of'water; with concentrations of dry calcium.
cyclamate equivalent in sweetness to the sucrose concentrations selected;
and without sweetener for a control.

The mean batch yield for custards increased significantly with the

increased weight of sweetener. Since differences in total weight of

1Type 10 Carrageenan manufactured by marine Colloids, Inc.,
Chicago 5 . Ill.

2Margel, a mixture of algin and calcium carbonate, manufactured
by Kelco Company, Chicago 6, Ill.

 

irgm‘lients

J

‘ stren '11}
gs.

variation in

   
  
  
 

Sigrifi
penetration I
or gelatin
camgeenan.
varied with
sweetened c“
gel strangt
an inverse
smhs set

For cc:
sucrose add
sucrose inc
findings.

The at
“Pength f
camgeena
as “‘6 cor.
with alfiir

calcium c‘

many Ellen Zabik

I

ingredients affect dilution of the gelling agent, it is conceivable that
gel strength differences apparent in this study may be due, in part, to
variation in batch yield.

Significant differences for gel strength were established from
penetration and per cent sag data. Custards gelled with algin preparation
or gelatin exhibited greater gel strength than custards gelled with
carrageenan. The rank order for gelatin and algin preparation custards
varied with the type and concentration of sweetener present. Sucrose-
sweetened custards gelled with algin preparation seemed to have greater
gel strength than sucrose-sweetened custards gelled with gelatin whereas
an inverse gel strength relationship occurred for cyclamate-sweetened
samples gelled with these two agents.

Per cent sag data showed rigidity of carrageenan gels decreased with
sucrose addition and this effect was greater as the concentration of
sucrose increased. Penetration data, however, did not support these
findings.

The addition of dry calcium 'cyclamate seemed to increase gel
strength for gelatin custards and to decrease gel strength for both
carrageenan and algin preparation custards. This effect was increased
as the concentration of calcium.cyc1amate was increased. Custards gelled
‘with algin preparation and sweetened with the higher concentration of
calciumtcyclamate exhibited the largest decrease in rigidity.

Variance in the weight of drainage due to syneresis among treat-
ments was found to be significant. Syneresis was evident only for
custards gelled with carrageenan and drainage appeared to be enhanced
by the addition of dry calcium cyclamate.

 

The {‘1'

 

a hmction c

 

Suggested a:

of gelling :1

sodium cycle!

 

warranted tc
”mgeenan

drainage,

 

 

Many Ellen Zabik

The findings of this limited stucbr indicate custard gel strength is
a function of gelling agent and type and concentration of sweetener used.
Suggested areas for supplementary study include equilibrating the amount
of gelling agent used with total weight of ingredients and/or substituting
sodium cyclamate for calcium cyclamate. Further investigations are
warranted to establish whether syneresis is inherent in the milk-type

carrageenan gel or whether formula modification can overcome this
drainage.

 

THE EFFECT OF SUCROSE AND CALCIUM CYCLAMATE
UPON THE GEL STRENGTH OF SELECTED GELLING AGENTS

IN THE PREPARATION OF JELLIED CUSTARD

By

Mhry Ellen Zabik

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Foods and Nutrition

1961

 

   
   
 

The mi
02'. Grace 5‘:

the prepay-3‘

 

‘ten for
“howledgm
Project and

The w:-
German F00
fenWShip

pmvi'iEd at

 

r...’
“3&9,1

, :a- u

ACKNOWLEDGMENTS

The writer wishes to eXpress her gratitude and appreciation to
Dr. Grace Miller for her generous guidance and encouragement throughout
the preparation of this thesis. The author wishes to thank Dr. William
Eaten for his assistance in statistical analysis of the data. Grateful
acknowledgment is also due to Dr. Evelyn Jones for her interest in the
project and her assistance in reading the manuscript.

The writer wishes to acknowledge her special indebtedness to
General Foods Corporation. White Plains. New Ybrk. fer granting her a

fellowship to study for this degree and for additional funds which
provided support for this project.

ii

 

  
   

LIST 0!" FIG?
ImeDUCTICEI
ENTER 0? II

Gelatin

E)

ACIQQCMIEDGMENTS . . . .
LIST OF TABLES . . . .
LISTOF'FIGURES. . . .
Immmflmn.....
REVIEW OF LITERATURE .

Gelatin e e e e e

Collagen source

Manufacturing procedures

TABLE OF CONTENTS

Composition 0 e e e e 0

Gel formation . . . . .

Gel strength

Carrageenan . . . . . . . .

Carrageenan source

Manufacturing procedures

Page

......OOOOOOOOOViii

e
e
e
e
e
e
e
e
e
e
e
e
e
e
e

CD 00 \n ‘U‘ \n I? #4

............... 10
............... 13
............... 11$
............... 1h

COMPOBition e e e e e e e e e e e e e e e e e e e e e e 16

ROSCLiOfl Of carrageenan With Milk e e e e e e e e e e e 18

Gol.formation e e e e e e e e e e e e e e e e e e e e e 19

Gel strength

.0...

Alginlc ACid e e e e e e e e

Alginic acid source . .

manufacturing procedures
Campositdsui.. e e e e e e

691 formation 0 e e e e 0

Gel strength

. . . . . . . . . . . . . . . 19
............... 21
...............22
............... 23
............... 25
............... 25
. . . . . . . . . . . . . . . 26

iii

 

 

 

 

 

 

 

N :

hvp
x.‘

TABLE OF CONTENTS (CONT.)

Page

Commercial Applications of Gelling Agents . . . . . . . . . 28
Gel Strength Measurements . . . . . . . . . . . . . . . . . 30
Bloom gelometer . . . . . . . . . . . . . . . . . . . . 3O
Bloucherjellytester................. 30
TarrbBaker jelly tester . . . . . . . . . . . . . . . . 31
Fuchs penetrometer . . . . . . . . . . . . . . . . . . 3l
Exchangejellytester................. 32
Recording gel tester . . . . . . . . . . . . . . . . . 32
PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Preliminarylnvestigation................. 33
Basic Formula . . . . . . . . . . . . . . . . . . . . . . . 35
Formula modification . . . . . . . . . . . . . . . . . 35
Ingredient Procurement . . . . . . . . . . . . . . . . . . . 36
Basic formula ingredients . . . . . . . . . . . . . . . 37
Gelling agents . . . . . . . . . . . . . . . . . . . . 37
Sweetening agents . . . . . . . . . . . . . . . . . . . 38
Batch Size . . . . . . . . . . . . . . . . . . . s . . . . . 38
Prepreparation of Ingredients . . . . . . . . . . . . . . . 38
Cooking Process . . . . . . . . . . . . . . . . . . . . . . 39
Preparation of Samples . . . . . . . . . . . . . . . . . . . #1
Objective Measurements . . . . . . . . . . . . . . . . . . . “2
Penetration . . . . . . . . . . . . . . . . . . . . . . #2

Per cent sag . . . . . . . . . . . . . . . . . . . . . #3

Syneresis.......................1+5

iv

TABLE OF CONTENTS (CONT.)

Page

pH . . . . . . . . . . . . . . . . . . . . . . . . . . #5

Analysis of the data . . . . . . . . . . . . . . . .
RESULTS AND DISCUSSION . . . . . . e . . . . .
‘Water Hardness and Physical Factors . . . . . . . . .

pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Batch Yield . . . . . . . . . . . . . . . . . . . . . . . . 49
Time-Temperature Relationships During Cooking . . . . . . . 51
Heating curves of milk . . . . . . . . . . . . . . . . 52

Time-temperature curves for 15-minute holding period
at 77-100 e e e e e e e e e e e e e e e e e e e e e e e 52

Heating curves after egg-milk mixture addition . . . .

81

081 Strength and Syneresis Tests 0 e e e e e e e e e e e e e

‘43

Penetration . . . . . . . . . . . . . . . . . . . . . . 58

Per cent sag . . . . . . . . . . . . . . . . . . . . . 62

Syneresis . . . . . . . . . . . . . . . . . . . . . . . 68

Texture of Non-sweetened Jellied Custard . . . . . . . . . . 70
SUMMARY.AND CONCLUSIONS . . . . e . . . . . . . . e . e . . . . e 73
mmcm........................78

muC......OOOOOOO......OOOOOOOO 83

 

 

9.

 

my
C

3r? I

LIST OF TABLES

Table Page
1e Design Of CerriMOnte e e e e e e e e e e e e e e e e e e e e 36

2. Cooking procedures for jellied custard made with pure
gelatin. carrageenan, and algin preparation. . . . . . . . . no

3. Treatment means and sweetener conglomerate averages for
batch yield Of Jellied custard. e e e e e e e e e e e e e e e 50

4. Analysis of variance for batch yield of jellied custards. . . 51

5. Summary of penetrometer values for jellied custard: treat-
ment means and conglomerate averages for gelling and
sweetening agents (m1111mater5)e e e e e e e e e e e e e e e 58

6. Mean squares and rank order of significant differences for
penetration Of jellied custard. e e e e e e e e e e e e e e e 59

7. Summary of per cent sag values for jellied custard: treat-
ment means and conglomerate averages for gelling and
sweetening agentS. e e e e e e e e e e e e e e e e e e e e 0 6n

8. Mean squares and rank order of significant differences for _
per cent sag Of jellied custard. e e e e e e e e e e e e e e 65

9. Summary of drainage values for jellied custard: treatment
means and conglomerate averages for gelling and sweetening
agents (gram3)e e e e e e o e o e e e p e e e e e e e e e e e 68

10. Mean squares and rank order of significant differences for
drainage 0: jellisd custard. e e e e . e e e e e e e e e e e 69

11. Mean penetrometer values for gel strength equilibration
(millimeters). e e e e e e e e e e e e e e e e e e e e e e e 8hr

12. Analysis of variance of mean penetrometer values for gel
strength equilibration. e e e e e e e e {,0 e e e e e e e e e an

13. Medified experimental formulas used in the preparation of
Jellied custard. e e e e e e e e e e e D e e e e e e e e e e 85

1“. Water hardness, physical factors, and pflvfor jellied custard
made with three gelling agents and two concentrations of two
SWBGtODOPSeae e e e e e e e e e e e e e e e e e e e e e . e e 86

 

Table

C
4".

16.

7.

Peru-ripe:1
treat”?

I
sweetenfi

Per Cen.
means,
agents.

Drainag
”fit an;
Weeten

LIST or TABLES (coma)

Table Page

15. Ponetrometer values for Jellied custard: original data,
treatment means, and conglomerate averages for gelling and
sweetening agents (millimeterS). e e e e e e e e e e e e e e 87

16. Per cent sag for Jellied custard: original data, treatment
means, and conglomerate averages for gelling and sweetening

aEOUtSe e e e e e e e e e e e e e e e e e e e e e e e e e e e 88

17. Drainage values for jellied custard: original data, treat-
ment means, and conglomerate averages for gelling and
sweetening agents (grams). e e e e e e e e e e e e e e e e e 89

 

 

 

 

 

with tut
ontrcl

J0 Initial

three g

6' M. 5m
thm: I

LIST OF FIGURES

Figure Page

1. Measuring penetration after release of ISO-gram cone
attaChmBnte e e e e e e e e e e e e e e e e e e e e e e e e e “u

2. Apparatus for height measurement of free-standing inverted
3611186 custard. e e e e e e e e e e e e e e e e e e e e e e u“

3. Equipment used for drainage weight determinations from free-
standing inverted Jellifid CUStardSe e e e e e e e e e e e e e “6

h. Mean time-temperature relationships for three gelling agents
with two concentrations of two types of sweeteners am! a
control during the 15-minute holding period. . . . . . . . . 53

5. Initial inverted heights of jenied custards prepared with
three gelling agents and five concentrations of sweetener. . 63

6. Wt surfaces of non-sweetened jellied custard prepared with
three gelling agentS. e e-e e e e e e e e e e e e e e e e e e 72

viii

INTRODUCTION

The curtailed availability of agar and gum arabic from European
sources during world‘war II resulted in the development of polysaccharides
from seaweeds as effective industrial substitutes. Recent advances in
the application of these marine hydrocolloids, particularly, the
carrageenates and the alginates, to the manufacture of industrial products
requiring controlled gelation and/or stabilization have stimulated interest
in the feasibility of their use as gelling agents and stabilizers in food
preparation.

Carrageenan1 is extracted from certain salt water plants, variously
called Irish Hess or carrageen (rock) moss, which are designated more
exactly as Chrondus crigggg or Gigartina stellata in the class
Rhodoggzceae or red algae, whereas alginic acid is extracted from a
number of different species and genera all of which belong to the class
Phaeoggzceae or brown algae. Both the Eastern and western coastal waters
of the United States serve as readily available sources of the brown and
red algae. However, the brown algae grows prolifically in polar and
temperate climates while it shuns tropical regions; therefore the
.principal American sources of the alginates are the giant kelp,
Macroczstis Ezrifera, located in the Pacific coastal.waters from Alaska

to California and the Laminaria digitata found in the North Atlantic

——_

1Carrageenan is the recommended nomenclature of the American
Chemical Society. It is also referred to as carrageenin, carragenin,
carrageen, carragheen, carragheenin, Irish Moss, and Irish Moss
Extractive.

Ocean, particularly in the coastal waters of Nova Scotia. In contrast
to this, the red algae flourishes in more temperate climates; thus the
coastal.waters of Florida and California are the principal American
sources of carrageenan, which in the United States is obtained almost
entirely'fron.§h:gndns_gzisnns.

Although the gelation and/or stabilization properties of the
carrageenates and the alginates have been established, the literature
contains little basic information relative to the gelling efficiency of
these products in contrast with agents, such as cornstarch and gelatin,
which are more commonly used in feed preparation.

The effect of sucrose upon the gel strength of gelatin desserts has
been firmly established. little is known about the effect of artificial
sweeteners, such as calcium cyclamate and sodiumbcyclamate, upon the
functional efficiency of gelatin in such products. The effect of sucrose
and/or artificial sweeteners upon the gel strength of desserts prepared
with marine hydrocolloids has not been reported in the literature.

If marine hydrocolloids can be used successfully in food preparation,
they 1:111 be potential additions to the types of gelling agents and/or
stabilizers currently available to the food service operator. ZHoreover,
if it is possible to substitute artificial sweeteners for sucrose in the
preparation of molded desserts made with gelatin, carrageenates, and/or
alginates without sacrificing the quality of these products, such menu
items could increase the variety of desserts available fer’diets with
sucrose restrictions.

The purpose of this investigation is to compare the effect of two

concentrations of sucrose and two concentrations of calcium.cyclamate

‘ (comparable in sweetness to the concentrations of sucrose tested) upon
the gel strength of custards made with pure gelatin, carrageenan, and
alginic acid. The gel strength data will be examined to detemine (a) the
practicability of using carrageenates and/ or alginates as gelling agents
in the preparation of Jellied milk-type desserts and (b) the possibility
of substituting calcium cyclamate for sucrose in the preparation of
Jellied milk-type desserts made with pure gelatin, carrageenan, and
alginic acid.

REVIEWOF LITERATURE

The gelation process and the gel structures formed in heterogeneous
mixtures such as organic gels are complex. Three theories of structural
formation, advanced by various investigators and summarized by Weiser (72),
are: (a) gels are composed of crystalline threads, (b) gels are made up
of a framework of amorphous threads, and (c) gels are not composed of
either crystalline or amorphous threads but are irregular groupings of
particles. Each theory is probably correct in specific cases. Further-
more, it is possible various arrangements of molecular aggregates occur
simultaneously in the same gel. In all cases it seems probable that the
particles are highly ludrous as a result of adsorption or absorption and
that they are linked together, forming an irregular mesh or network which
entrains liquid in the interstices.

Practically all of the organic gelling agents swell in the presence
of suitable liquids or vapors and, with preper temperatures, will peptize
to form sols which are influenced by pH and presence of salts. Elastic
gels formed from these agents lose water continuously in dry air; stone—
over with proper temperatures and humidity twdration will occur. These
gels exhibit aging, which may manifest itself by agglomeration of
colloidal particles to form denser aggregates which can absorb and entrain
less liquid than the freshly prepared system. The aged system exudes
liquid, a phenomenon called syneresis. Syneresis appears to be influenced
by setting time; the quicker the gel sets the sooner syneresis occurs and
the more rapid the initial velocity of the process. In addition, each
organic gelling agent is affected by its own source and method of manu-
facture as well as characteristics peculiar to that agent alone.

Gelatin

Gelatin is the collective term for an extremely heterogeneous protein
composed of mam-sized polypeptides. Gelatin's main distinction rests in
its ability to for: gels at relatively low concentrations. Anding (6)
describes “pure” dry gelatin as a tasteless, odorless, transparent,
brittle, glasslike solid, very faint yellow to amber in color. Although
gelatin never occurs in nature, it is derived from the animl constituent
collagen by an irreversible turdrolytic process. The gelling efficiency
of any gelatin sample is a function of the collagen source, method of
manufacture, thermal history, pH, presence of electrolytes, presence

of non-electrolytes, concentration, and molecular weight.

Collagen source
Collagen, the principal intercellular constituent of the white

connective tissue of animal skins and bones, is the essential raw material
of gelatin. Collagen is procured from hides obtained in the United States
and imported from South America and England and from bones imported from
South America and India. Pigskins as well as cattle hides are used
extensively in the United States whereas the production of gelatin from
ossein, the organic material left after the removal of minerals from bone,
is less. In contrast to this, Europe produces 20 to 30 per cent more
gelatin from ossein than from hides.

thfactm procedures
Modern procedures in gelatin manufacture are all designed to render

collagen more readily convertible to gelatin. This is accomplished by
previous chemical treatment, either alkaline or acid processing, which

reduces the time gelatin is exposed to high temperatures and therety
reduces degradation of the product.

Alkaline flees {$2. For this method the raw materials are soaked

in a calcium hydroxide suspension for l to 6 months at pH 12 to l2.5 at
temperature of the surrounding air. ‘lhe total amount of lime used is
approximately 10 per cent of the weight of the stock although considerably
less is mquired if either sodium hydroxide or sodium carbonate is also
used. High concentrations of soluble alkali are disadvantageous due to
their corrosive action on skin causing a loss of material while inner
portions remain unaltered. “evertheless, concentrations of approximately
1 per cent are often used to "sharpen up“ lime liquors. liming changes
collagen into a form which is more easily converted to gelatin as well
as removes a number of impurities insuring gelatins of better color and
clarity. After liming is finished, the materials are washed with clear
water and/ or dilute acid to affect complete removal of the alkali before
extraction. Acid hastens the process, increases swelling, and removes
salts.

In a laboratory experiment on dried sinew, Amos (it) found both
yield and gel strength increase with increased time of lining and with
approximately 3 months of liming a gelatin with a bloom value of 250
could be produced. In previous experiments Amos (5) attempted to
shorten the lime soak by ”sharpening" the liquor. He reported that at
temperatures ranging from 16 to 20°C, the maximum safe concentrations
of sodium ludroxide and sodium carbonate which could be used along with
the lime soak were 0.5 and 0.? per cent, respectively. Increasing the

temperature of the soak above 22 to 25°C hastened the swelling time but

produced an inferior product and caused destruction of the stock. Amos
also stated that soluble alkali could not be used along with the lime

soak at increased temperatures.

Acid process (262. Acid processing is used primarily for frozen pigskins
in the United States and for'ossein in Europe. Pigskins, previously

frozen into molds of approximately 100 pounds, are thawed with water
washes, soaked in dilute solutions of hydrochloric, sulfuric, or phos-
phoric acid until penetrated, and washed with fresh water until sufficient
acid is removed to elevate the pH to h, the desired acidity for cooking.

it this pH impurities are relatively'inscluble and remain as residue at
the end of extraction.

E3tzggti2n._{113:3§122‘_2z21ngp Gelatin from either lined or acidified

stock is extracted with successive portions of water increasing in
temperature from 55 to 100°C. Anding (6) reported the following
extraction data: first extraction at 55 to 65°C for h to 9 hours yields
5 to 10 per cent gelatin, second extraction at 65 to 75°C for h to 8
hours yields 3 to 6 per cent gelatin, third extraction at 75 to 85°C for
h to 6 hours yields 3 to 6 per cent gelatin, fourth extraction at 85 to
95°C for h to 6 hours yields 2 to # per cent gelatin, and the final
extraction at 95 to 100°C for 2 to h hours yields 1 to 2 per cent gelatin.
Idson and Braswell (36) have stated the increasing temperature of each
successive cock causes the gel-forming power to drop. These gelatin
liquors are filtered through pressure filters and the filtrate is placed
in a multiple-effect evaporator where 50 to 75 Per cent of water is

removed. The initial stage of drying, accomplished with a 32°C drybbulb,

reduces the moisture content to 20 to 30 per cent. This step is followed
by humidity-controlled hot drying at 32 to 60°C which reduces the moisture
to approximately 10 per cent. Finally the dried residue is treated
mechanically to produce the desired pmsical fem: sheet, flake, or

make

Miss
Gelatin is composed of a minimum of eighteen different amino acids

linked together in a partially ordered fashion. Numerous investigators
have established an accurate amino acid pattern for gelatin. Idscn and
Braswell (36) reported the composition of the gelatin molecule as
approximately 1/3 glycine, 1/3 cyclic amino acids such as proline and
Ivdroxyproline, 1/5 dibasic or diacidic amino acids, and small amounts
of a variety of other amino acids. Functional groups of gelatin reported
W Ward (71) are the amino, imidazole, gusnidino, carbonyl, Wdroxyl,
and peptide bond groups. The first three carry a positive charge, the
carboxyl carries a negative charge, and the last two carry no charge.
Although the composition of gelatins from alkaline or acid processes

is similar, Ward reported more carboxyl groups in alloline- than in
acid-processed gelatin.

92); formation

Gelation is the formation of a gel or the solidification of a sol.
Lowe (39) pointed out that one of the outstanding characteristics of
gelatin is its ability to form a sol at 35°C or higher and, with high
enough concentration, a gel at lower temperatures. This sol-gel trans-

formation is themlly reversible. Accompaming gelation the following

changes occur in the gelatin system: changes in viscosity, rigidity,
elasticity, optical rotation, surface films, electrical conductivity,
and I-ray diagrams. Perry (22) stated rigidity, a characteristic
common to all gels, appears suddenly at the moment of gelation and the
changes in optical rotation which occur with time follow very closely
rigidity changes. Richardson (51*) proposed that the acquirement of
elasticity distinguishes the gel from a suspension. Viscosity of sol
and rigidity of gel my run parallel, but this is not always true for
gelatins giving the most viscous sols do not always yield the stiffest
gels.

Ferry (22) correlated the general theories applying to the mechanism
of gelation of gelatin and presented evidence that individual molecular
chains are bound together by secondary attractive forces localized at
widely separated points. This locus of attraction actually includes
several amino acid residues. In contrast, at the isoelectric point
non-localised forces are predominate if there is no salt present. From
their studies of the change in optical activity accomparwing gelation,
Ferry and Eldridge (23) concluded the rigidity of a gel is due to intra-
mclecular crosslinks or intramlecular rearrangement, while comparatively
small contributions are made by intermolecular links.

Boedtker and Doty (11), from their studies of aggregate and gel
formation in gelatin systems, proposed association occurs through
crystallite formation. This thesis is supported by the dependency of
aggregate size on thermal history of the sample, a characteristic of
polycrystalline materials. These investigators reported ionic strength

of the sol did not appreciably influence bond formation, concluded

10

electrostatic forces do not play a dominant role, and suggested the
reclaiming possibilities of twdrcgen bonds, dispersion forces, and dipole
interaction do contribute.

Earlier Ferry (22) presented evidence for two kinds of Van der Waals
forces, ludrogen bonds and nonpolar attractions, which are presumed to
be important in gelation of proteins and suggested both of these might
be involved in the gelation of gelatin. The exact location of the bonding
forces is not known; however Morel an! Grabar (M) believe the guanidine
group is essential to the formation of gelatin gels. Oxidative
destruction of #5 per cent of the arginine prevented gel formation
whereas milder oxidation without destroying the arginine weakened but did
not destroy the ability of the gelatin to form a gel. These cc-wcrkers
also reported destruction of 20 per cent of arginine and 15 per cent of
hydroxyproline destroyed the gel forming power. Thus, it is suggested
the hydroxyl groups are secondarily involved. Idscn and Braswell (36)
indicated Gustavson supported the possible important role of Ivdrogen
bonds of the keto-imide linkage and Kinchingtcn disputed the role of
arginine in the gelling process.

92.1 m

Idscn and Braswell (36) stated when a stress is placed upon a
gelatin gel for a short time, the gelatin gel gives by an amount pro-
portional to the applied force. Resistance to stress is a function of
rigidity or gel strength and is affected by the collagen source, method
of manufacture, and previous thermal history of the gelatin sample. In
addition to these, gel strength is also influenced by the presence of

electrolytes and/or non-electrolytes, pH, time and temperature of setting,

concentration, and molecular weight.

 

VIII

 

.I .. Vlv hill Iii-III!

11

W. Gelation temperature is affected by the
presence of electrolytes. Lowe (39) pointed out substances which lower
the melting point of gelatin also decrease rigidity. Iowe stated the
effect of anions at equal concentrations is usually given for above the
isoelectric point as follows: sulfate > citrate > tartrate > acetate >
chloride ) chlorate > nitrate > bromide > iodide. Sulfate usually
elevates the gelation temperature, while iodide may lower the gelation
temperature below 0°C. Belle et a1 (9) found fluoride increased the
melting point whereas salicylate, tribromoacetate, and diiodisalicylate
prevented gelation. The lowering of melting point was explained as the
result of materials breaking peptide kudrogen bonds which were involved
in mintaining the intramlecular crosslinks. The effectiveness of
certain large ions as melting point reducers may be due to their ability
to cover the peptide groups. The anions which raise the melting point
may do so by protecting ordered segments of gelatin from denaturation by
water or w cross-linking through interaction at the peptide links.

Lowe (39) suggested cations may have more effects than anions below
the isoelectric point. Nobel (1+8) found all alkali metal cations had
the same effect on elasticity of gelatin gels except lithium which had a
slightly greater effect. The range of alkaline earth cations is as
follows: barium ) strontium ) calcium ) cesium I magnesium. All of
these had a greater effect than water alone. Dahlberg et al (18) reported
greater gel strength in milk systems than in water and stated the presence

of salts in milk may be one reason for altemd gel strength.

We Norman and Shearer (25) studied the
effect of sucrose, urea, and levulose upon the setting time of gelatin

solutions. Small concentrations of non-electrolytes increased setting
time; this effect was maximum at 0.02 to 0.03 M. Gelatin gels set more
rapidly at concentrations exceeding 0.1 M. than in the absence of non-
electrolytes; however 0.2 M. was the highest concentration they used.
These workers found diffusion velocity varied directly with time of
setting and slower setting gels exhibited a more open structure. Advani
and Narwani (1) stated aldo and keto sugars condense with amino acid
groups of a gelatin sol. Although this phenomenon does not occur with
non-reducing disaccharides, there is a decrease in the free solvent of
the system due to hydration of sugar.

2g. Boedtker and Doty (11) found gels formed at the isoelectric point in
the absence of salts are weak; nevertheless, if the pH is more than one
unit away from the isoelectric point, weak gels are no longer formed.
With sufficient salt present pH makes little difference. Idscn and
Braswell (36) cited the following data of Gerngross: for a 10 per cent
gelatin solution rigidity was independent of pH between 4.1; and 9.0, for
a 3 per cent solution rigidity was independent between “.6 and 8.2, and

for a 1.5 per cent solution the rigidity was independent of pH between
“.3 am 6.70

W. Lows (39) indicated the slower a gelatin solution is
cooled the higher the temperature of gelation; all gels become firmer at
low temperatures than at high temperatures: and above 35°C no gel is
formed at any concentration of gelatin. Moreover, after a gel has formed,
its firmness increases with time of standing. Perry (21) stated rigidity

decreases rapidly with increasing temperature and vanishes at about 30°C.

13

Gels cooled at 15°C develop high rigidity whereas gels cooled at 0°C and
then returned to 15°C take ten times as long to develop comparable
rigidity. This phenomenon was further studied by Eldridge and Ferry (l9) .
Their results show some crosslinks are more stable than others. Thus,
when gelation is allowed to proceed slowly stable crosslinks are formed.
However, when the solution is chilled rapidly, crosslinks are formed in a
haphazard manner. Assuring the cross-linked bonds to be Ivdrogen bonds,
these workers analyzed the heats of formation data and estimated that a
single cross-linking loci may consist of less than 10 or as many as 1&5
hydrogen bonds which contribute to differences in stability.

Concentration, molecular; weight. Ferry and Eldridge (19, 23) have
expressed rigidity of gelatin gels as a linear function of approximately
the square of the concentration with slight deviations resulting from
physical conditions and previous history. They also expressed the square
root of the rigidity as a linear function of weight—average molecular
weight. In an earlier study Ferry (21) reported rigidity is influenced
more by preparation procedure than by the actual molecular weight.

love (39) said the setting time is shortened with increasing concentra-

tion; nevertheless 1.5 to it per cent is the normal range for food

preparation.
Carrageenan

Carrageenan is a water soluble polysaccharide extracted from
naturally abundant red seaplants. These twdrocolloids are strongly
negatively- charged polymers of high molecular weight having unique and

useful properties. It is now lmown that the carrageenan molecule consists

lb

of two chemically different constituents, designated as kappa- (H -) and
lambda- (A -) carrageenan, which are present in about equal amounts.

The use of carrageenan in the preparation of blanc mange puddings, cough
sirups, and hand lotions dates back to colonial times. The highly

refined product now in widespread use is the result of advancements in
manufacturing procedures spurred by the demand for substitutes for agar

and gum arahic whose availability was sharply curtailed during World War II.
The properties of am given carrageenan sample are a function of the

method of manufacture, the previous thermal history, presence of

electrolytes, pH, and the presence of other reactants.

Carragggggn m

Carrageenan is extracted from certain salt water plants, variously
called Irish Moss or carrageen (rock moss), which are designated more
exactly as Chrondus crismgs or Gigantina stellata in the class
ghodomcsae or red algae. Idscn (35) stated almost all the carra-

geenan processed in the United States is obtained from the Chrondus

m. Red seaweed exist principally in both the Eastern and Western
coastal waters: howmrer they flourish in more temperate climates and are
most abundant in the warmer waters off the Floridan, Californian, and

Mexican shores. Abroad, red algae abound in the coastal waters of India,
Malaya, Australia, and the Pacific Isles.

Manufactu_n__ng pgocedures
W0 @1333 EM grows from a disc-like root which attaches
itself to rocks in relatively shallow coastal waters. The moss is

usually gathered by hand when the tide recedes or raked from below the

15

surface of the water (70). Seasonal variations make harvesting more
profitable during certain times of year and give products with different
gelation quality. The difference in products is apparently related to
sexual.maturity of the algae. Preliminary drying, resulting in 80 per
cent moisture loss, is followed by controlled washings to leach out
color pigments. According to Marshall and Orr (#0) gelling quality of

the product is improved by a storage period between these two steps.

Qgtzgction. Carrageenan can he leached from the seaweed by water at
various temperatures or it may be precipitated from.a seaweed solution
by alcohol.

The temperature of water for extraction has a pronounced effect
upon the preperties of the carrageenan sample. Fulton and Hetcalf (26)
reported the cold water fraction had 1/6 the gel strength of the hot
water fraction. Data from three extraction temperatures, cold, #0 to
50°C; hot, 80 to 100°C; and pressure, 115 to 120°C, used by Rose (55)
showed only the hot extract had gel strength. Furthermore, a l to 2
per cent solution of the hot extract gelled readily. More recently
Goring and Young (30) found a certain quantity of gelation with extracts
at 30, 60, and 100 to 120°C; however there was a pronounced maximum gel

strength with the 60°C extraction. In conjunction with the fractionation
of the two constituents of carrageenan, Smith and Cook (60) first
extracted the solution at 60°C and then extracted the residue at 100°C.
The fractions contained 64 and 26 per cent H - and X -carrageenan,
respectively, at 60°C and 1b and 78 per cent at 100°C. Marshall and

Orr (#0) reported gel strength of the pressure extract could be improved

16

by treatment with an alkaline solution. An acid treatment hydrolyzes

the extract rapidly destroying its gel forming capacity whereas a certain
degree of alkaline hydrolysis produces a substance more sensitive to
gelation.

Filtration. gazing. Following extraction, the carrageenan solution is
clarified and filtered. The product may be bleached.with hydrogen
peroxide; however this practice has been found to have a deteriorative
effect upon the gelling power'and viscosity of the carrageenan sol. The
product is partially'evaporated under vacuum and then either spray dried
or completely vacuum dried. In the land process as reviewed by Teeng (69)
addition of sugars such as sucrose or dextrose to the carrageenan solution
has been advocated in order to protect carrageenan from deterioration
during evaporation and drying. In this way the moisture content could

be reduced to 2 to 3 per cent whereas without sugar protection, drying

to 10 to 12 per cent gave a product susceptible to deterioration.

Co 3 t n

The ashpfree polysaccharide is composed of Db and L-galactose,
3,6-anhydro-Dbga1actose, and sulfate ester groups. Rose (55) confirmed
the earlier work of Haas and Russelléwells (32) by showing hot and cold
water extractions of Chrondus crispus gave two polysaccharides of
different Optical rotation although Buchanan et al (13) have proved the
galactose portions of both to be similar.

The chemical heterogeneity of carrageenan has been supported by
recent electrophoretic, sedimentation, and diffusion studies. Cook and

associates (15) found the macromolecule was composed of two components,

17

one appeared to be linear and the other branched. These two components
'were separated by fractionation*with potassium chloride by Smith and Cook
(60). At approximately 0.15 M. potassium chloride one component pre-
cipitates as a gel, designated as the H -carrageenan, which is removed
from the unaffected fraction,ah -carrageenan, in the supernatant.

A complete methylation study of the structure of carrageenan is cited
by Smith and Montgomery (62). This method positions the sulfate group
on Cu and supports the oc 1.3 linkages with the possibility of some
branching on C6. These methylation studies were completed before the
fractionation of the two components. Following this development Smith
et a1 (61) reported the [Dd-portion contains D-galactose and 3,6-anlvdro-
D—galactose residues in ratio of approximately 1.431 together with 25
per cent esterified sulfate whereas the‘A -portion contains Dbgalactose
together with approximately 35 per cent esterified sulfate. These data
are supported by the work of O'Neill (b9. 50).

From infra-red and X-ray data, Hayley (8) proposed the stretched
fibers of carrageenan all have fiber periods of 25.2 A. Furthermore,
the fiber period of P(-carrageenan appeared to contain two trisaccharide
units, each composed of two sulfated 0<-Dbgalactose residues linked.o(193
and one 3,6-anlvdro-fi -D-galactose residue linked 1.4 and, within a
25.2 A. period, a single side chain residue of 3,6-anhydro-D—galactose
appeared to be linked through 06 of a sulfated Dbgalactose unit in the
main chain. The )x-carrageenan fiber period may represent 3 disaccharide
units, the majority'of which are composed of two l-BOCD-galactose sulfate
residues. Smith and Montgomery (62) have disgramed the generally

accepted chemical formula. Hansen and Whitney (33) dispOIOd the

18

composition of the H-carrageenan fiber period and have diagramed it
slightly differently.

5226151011 2; carragggn_an with milk
Carrageenan exhibits a specific reaction with milk which gives rise

to an increased stabilisation of suspended particles. Glabe and his
associates (28) reported 0.03 to 0.0h per cent carrageenan is necessary
to suspend one pound of cocoa in 100 pounds of milk whereas thirty times
as much carrageenan is needed to suspend the same amount of cocoa in an
equivalent weight of water. Rose and Cook (56) found the presence of
carrageenan increases the viscosity of Mlk to a point where the particle
size of ingredients such as cocoa is in a stable colloidal state.
Whether the increase in viscosity is due to a casein-carrageenan complex
or whether the carrageenan is associated with serum proteins is not fully
known.

Smith (59) stated l-L-carrageenan was more effective than A -car-
rageenan in increasing milk viscosity. However, with potassium depleted
milk, )\ ~carrageenan retained its original effect whereas K-carrageenan's
effect was greatly reduced. Moreover, the addition of potassium ions to
milk did not greatly increase the effect of H-carrageenan. The natural
potassium content of milk (0.04N.) seemed to be sufficient to develop
the full effect. Furthermore, the investigator found considerably more
carrageenan was necessary to affect a comparable viscosity increase in
0.014 N. potassium chloride than in milk. From these data anith con-
cluded ionic bonding of the anionic hydrocolloid with the potassium ion

did not account entirely for increased reactivity with milk.

l9

infatuation

Gel formation of carrageenan sols is a precipitation phenomenon,
involving ionic bonding between certain metallic cations and the strongly
negativelyacharged anionic polysaccharide. Both monovalent and bivalent
cations have the ability to form these ionic bonds although some are
much more effective than others. Bivalent cations form gel structures
by the formation of crosslinks between carrageenan chains whereas mono-
valent ions are involved in an intramolecular ionic bonding in which the
ion is thought to actually fit into the crystal lattice of the carrageenan
molecule. All carrageenan gels are thermally reversible. The exact
temperature at which the sol-gel transformation takes place depends upon

the concentration of ingredients present.

Gel stre h

Strength or rigidity of carrageenan gels is affected primarily by
temperature of sample extraction and by presence of electrolytes. In
addition, gel strength is a function of the presence of other ingredients,

pH, temperature, concentration, and molecular weight.

Presence 0f electrolytes, Although the presence of cations is essential
to formation of gels, not all cations will produce gels of the same
strength. Rice (53) noted potassium chloride was more effective than
calcium chloride which, in turn, was more effective than sodium chloride
in precipitating and setting carrageenan sols. Calcium.sa1ts produce a
weak gel structure beyond.which further salt addition has no effect (58).
Gels formed in the presence of both potassium and calcium salts tend

toward the strength produced by calcium ions with the gelling temperature

20

controlled by potassium ions. This conclusion has been supported by
Marshall and Orr (“0) who stated, in every case studied, potassium pro-
duced firmer gels than magnesium, sodium, ammonium, calcium, or lithium
salts. Stoloff (6“) observed the rank order of decreasing effectiveness
of cations for gel strength development capacity is potassium, ammonium,
calcium, magnesium, aluminum, and sodium.

In their studies on the fractional precipitation of the components
of carrageenan by potassium chloride, Smith and Cook (60) found certain
other monovalent cations, such as cesium or rubidium, were also effective
gelling agents whereas sodium and lithium were not. Through further
study, these investigators concluded the smaller ions fit into the
crystal lattice of1fiL-carrageenan, the component involved in gelation,
whereas the larger hydrated ions of sodium and lithium do not. None of

the ions noted above affected ht-carrageenan.

Presence of other added ingredients. Tressler and lemon (68) stated
the presence of solutes in colloidal solutions of carrageenan compete
with colloidal micelles for water resulting in altered colloidal
properties. In general, the greater the quantity of solute present the
greater the gel strength. The elastic texture of carrageenan gels
prepared with other polysaccharides or mono- or disaccharides present

indicates that weak hydrogen bonds are probably involved to some extent
in these systems (58).

‘EE. Carrageenan gels are relatively unaffected by pH unless the system
becomes acidic enough to cause hydrolysis and degradation of the polymer.

This condition usually occurs at pH 3.5 or lower and is accentuated by
heat (58).

Temperature. Carrageenan gels are thermally reversible and, in common
with other thermally reversible gels, they melt at higher temperatures
than those at which they were formed. Fulton and Metcalf (26) noted

a 2 per cent gel melts between 5“ and 60°C although it originally forms
between 38 and 10°C. The gel strength is slowly reduced by high temper-
atures. Rice (53) stated gelation temperature is dependent upon the
type and amount of salt present. Stoloff (61+) reported if sufficient
carrageenan was present to form a gel, the original gelling temperature
increased with increasing concentrations of potassium chloride and was

independent of the hydrocolloid concentration.

Concentration, molecular weight. Firm gels may be produced with as low
as 1.0 per cent carrageenan solutions. Stoloff (61+) stated, as the
hydrocolloid is purified, the concentration must be increased or the
temperature lowered to obtain a gel. Goring and Young (30) found,
although there is a slight relationship, the gel strength of carrageenan
gels was more dependent on structural factors than on the molecular

weight of the sample.
Alginic Acid

Alginic acid is the ioniziable polysaccharide of high molecular
weight extracted from naturally abundant brown algae. According to
Steiner and McNeely (63), although the m'drophillic colloidal substance
was discovered by Stanford in 1883, most of the comrcial development
and theoretical discoveries have materialized in the last few decades.
c"unnercial production of algin began in California in 1929 and, due to

“39 abundance and versatility of the product, has eXpanded until algin

22

is the most important natural water-soluble gum produced in the United
States. The versatility of the product has led to its use as thickening,
suspending, stabilizing, gel-producing, film-forming, and adhesive
agents.

The ten: “algin" was first used by Stanford for the product which
he later identified as sodium alginate. Since Stanford's time algin
has been used as a common name for sodium alginate although some authors
use the term to refer to all soluble salts of alginic acid or more
vaguely to all salts of alginic acid and to alginic acid itself.

The gel formation of the alginates is dependent upon the presence
of bivalent cations. In addition, the properties of algin samples are
affected by their source, method of manufacture, previous thermal history,

pH, and presence of electrolytes.

Alginic acid source

Alginic acid is extracted from a number of different species and
genera all belonging to the class W or brown algae in which
filginic acid occurs, along with cellulose and other polysaccharides, in
the cell wall. From data compiled for the First International Seaweed
SWsium held at Edinburgh in 1952, the major sources of brown algae
are reported as the American coastal waters of both Atlantic and Pacific
Oceans and the coastal water of Northwest Europe including those of
Nontay, Great Britain, France, and Spain; while less prolific beds are
located off Japan, Chile, South Africa, Australia, and New Zealand (35).
Thfiae brown algae flourish in temperate and in polar zones; thus the
giant kelp Macrocystis py'Lifera, principal sources of alginates on the

Pacific Coast. are found from Alaska to California whereas M

23

digitata, principal Atlantic sources, are located in coastal waters of

Nova Scotia.

Manufacturing_procedures

The grade or quality of the material is governed by temperature and
duration of water and/or acid washes and the method of precipitation of
calcium alginate. Fresh seaweed gives the best grade and predrying is
deleterious unless carried out at room temperature. Black et al (10)
observed that any form of thermal drying leads to depolymerisation of
highpgrade alginate present in fresh seaweed. However, airbdrying or
drying in a vacuum dessicator over calcium chloride gave no loss of

grade and drying over phosphorus pentoxide to almost anhydrous conditions
lowered the grade slightly.

Harvestigg. The giant kelp of the Pacific coast spreads out on the
surface of deep water and can be harvested by ocean-going mechanical
barges. The Lamigggi; grows under the water's surface and is gathered
by motor boats equipped with grappling hooks operating at depths of 10
to 20 feet. A small quantity is gathered as driftweed after a storm or
raked from the bottom in shallow waters (73).

Although a number of manufacturing processes have been developed
since the Stanford process was first used in nineteenth century Scotland,

the two processes most commonly used in the United States are the Algin

Corp. process and the Kelco process.

A C ratio 8 68 . In this process, patented by'le’Gloahec

and Berta in 1938, either fresh or dried Laminaria is soaked in a

2“

solution of calcium chloride. At the end of the soaking period the
seaweed is first washed with water, then with dilute hydrochloric acid
to remove any residual salts, and finally with water. The seaweed is
digested with.warm dilute sodium carbonate for approximately 3 hours at
room temperature with continuous agitation. The mass is diluted to
form an emulsion which, after the cellulose has been removed, yields a
crude solution of sodium alginate. The crude product is decolorized,
clarified, and precipitated with hydrochloric acid to give alginic acid.
This alginic acid may be dried at lbO to 160°F (60 to 71°C) or it may
be converted into alginates before shipping.

Kelco process (6Q; 59). This process, originally patented by Green in

1936, avoids heating the solutions over 50°F (10°C). Freshly harvested

Macrogzstis pyzifera is leached for several hours with weak hydrochloric
acid to reduce the salt content. The acid liquor is drained, then the
chopped or shredded kelp is digested at pH 10, brought about by sodium
carbonate addition, to give a gelatinous mass. Following a second soda
ash digestion, the product is completely disintegrated in a hammer mill.
This solution is clarified and filtered. The filtrate, containing
sodium alginate, is then treated.with 10 per cent calcium chloride to
precipitate the alginic acid as a calcium salt. The curdlike calcium
alginate is separated, washed, and bleached. It is then converted into
alginic acid by addition of hydrochloric acid. Repeated washings
constitute the final step; however alginic acid prepared in this way is
somewhat unstable and must be stored under refrigeration. Consequently

it is frequently'converied into a salt which can be dried for shipment.

25

Composition
Uhtil recently'alginic acid was generally accepted as a linear

polymer of anhydro-fi -D-mannuronic acid of high molecular weight linked

in such a way that each anhydromannuronic acid unit had one free carbonylic
acid group and two free hydroxyl groups. This concept of structure was
derived from fundamental investigations of Nelson and Cretcher (l7, #5)

in the late 1920's. Chanda et al (1h) reported results from studies
carried out on less degraded alginic acid which confirmed the view that
the main structural feature of the alginic acid molecule to be a chain

of l,h-linked-,6 -Dbmannuronic acid residues. X-ray analysis by Astbury (7)
had shown that the stretched fibers gave a well defined diffraction
pattern, indicating a high degree of orientation. Interpretations of
these data agreed with the concept of alginic acid as a linear chain.

More recent chromatographic studies done by Fischer and Dorfel (2”)

showed alginic acid‘was composed of L-guluronic as well as D-mannuronic
acid. Therefore more research will have to be done before the structure
of the alginic acid chain can be stated.

93} formation

Gelation of alginate sols is a precipitation reaction with cross-
bonding occurring between a negativelyacharged alginate anion and a
positivelybcharged cation supplied by the gelling agent. The gelation
process for alginate sols is not thermally reversible. Idscn (35)
reported sodium alginate solutions will form gels with acids or‘with
calcium salts.

The metallic cation gel structure has been studied hy a number of

investigators. Mbngar and wassermann (43) assume the main valency chains

26

in the stretched calcium alginate fibers are attached to each other in
a broadside-on position by salt bridges operating between the bivalent
calcium and the carbonyl groups of the polyanion. This formation of
crosslinks implies that segments of adjacent alginate chains are
relatively straight and approximately parallel to each other. A recent
investigation of Thiele and Andersen (65) supported the bonding theory
proposed. Moreover, they stated the orientation of the gel structure,
due to reproducible directed coagulation in converting the sol into a
gel, is influenced by the direction of flow of diffusing ions and by
the ion itself. A high degree of orientation is associated with
dehydration of the colloidal particles and with a small capacity for
swelling. Thiele and Hallich (66) in a later study of the ionotropic
gel formation of sodium alginate sols by the diffusion of ions found,
under suitable conditions, drape of water segregated. As gel formation
progressed in the direction of diffusion these liquid drops became
tapering capillaries that were straight, parallel, and often nearly
identical.with one another. The exact structure and size of the
capillaries were specific to the diffusing metal ion and were related

to the degree of ionotropic orientation produced by the ion.

93; strength

The gel strength or rigidity of an alginate gel depends largely
upon the presence of electrolytes. These gels are also influenced to
some extent by pH and concentration. Unlike the other gel systems

previously reviewed they are not thermally reversible and do not require
chilling for gelation to occur (#1).

 

27

Presence of electrggytes. Gelation of alginate sols requires the
presence of certain metal cations. Thiele and Andersen (65) reported I
differences in the degree of orientation of iouotropic gels due to the
directing ability of the gelling cation. This directing ability decreases
from lead to copper to cadiwm to barium to calcium. Scott (57) presented
another phase in the effect of electrolytes upon gel strength of poly5
carboxylates such as the alginates. Complexes which had been formed by ”Hal
polyanions with cationic detergents were soluble in salt solutions at

concentrations characteristic to the structure of the polyanion polymer.

 

For alginates 0.33 N. potassium chloride or 0.30 N. magnesium chloride
had sufficient ionic strength to maintain 70 per cent of the poly; ;_;“

saccharide in solution.

‘EE. At extremes of the pH scale alginate solutions‘will thicken and

form gels without the addition of bivalent cations. Algin solutions are
unaffected by pH ranging from “.5 to 12. Below pH h.5 the solutions
thicken, gel, and finally at pH 3 alginic acid is precipitated. The
processor (2) stated the alginates with the exception of propylene glycol
alginate which is resistant to both excessive acid or alkali, will

thicken and form weak gels at pH's above 12.

Concentration. Steiner and McNeely (63) preposed firmness of alginate
gels is a function of both the concentration of the alginate and the
bivalent ions present. Gibson and Rothe (27) stated 0.8 per cent sodium

alginate gives desirable dessert gels or*milk puddings.

 

28

Commercial Applications of Gelling Agents

The most important quantitative use of gelatin in the food industry
is in the manufacture of gelatin desserts. Gelatin is also used
extensively in the stabilization of marshmallow foams. In baked products
gelatin acts as a stabilizing agent in chiffon-type fillings thus pre-
venting syneresis; and in icings, particularly the boiled type, it not Fa»
only serves as a setting material but has some influence on sugar crystal- I
lization. In the dairy industry gelatin stabilizes ice cream by pre-

551' ‘;’h. filo

venting crystal growth. Gelatin is also used in the preparation of

4.1:

Jellied meats and madrilene soups. Idson and Braswell (36) ranked

I‘

capsule preparation first in the use of gelatin in the pharmaceutical
industry. In pills, tablets, and lozenges gelatin has found application
as a binding agent and for coating and glazing purposes. Stable
emulsions of mineral oils, caster oil, and vitaminpcontaining fish oils
are among the many prepared with gelatin as the emulsifying agent.
Feeding tests (47) have shown carrageenan to be completely harmless
in amounts normally used in foods and it has been accepted as a safe
food additive by the Federal Food and Drug Administration (20). The first
major use of carrageenan in foods was for the stabilization of cocoa
particles in chocolate milk. A more recent list of uses presented by
Glabe et a1 (29) includes the strengthening of wheat gluten to produce
a firmer spaghetti, the texture improvement of white cakes, and the
production of quick-drying icings. Various carrageenan types have been
recommended (58) for use in stabilizing whipping cream and ice cream,
producing milk-base puddings and pie fillings, producing water-type
dessert gels, stabilizing and thickening fruit pie fillings, stabilizing
hand lotions and cough sirups, and emulsifying mineral oils.

29

Algin has been eaten for hundreds of years as a constituent of

kelp while algin itself has been used in various foodstuffs for a quarter
of a century. Extensive animal feeding tests (06, 51) have shown that
algin is nontoxic and not an allergen. According to Gibson and Rothe (27)
propylene glycol alginate has found extensive use as a thickening and
emulsifying agent in French dressings and is one of the Optional
emulsifying agents listed by the F.D.A. Steiner and McNeely'(63) fm-fi
enumerated a number of other uses. The addition of algin to milk in

special formulation produced a soft custard-type pudding. Fruit Juice

 

gels have been prepared by the addition of calcium ions and algin.

If,” -..-_‘ '

Formula adjustments produce firmer gels useful in candies. In Germany
some interest has been shown in the use of algin films as edible coatings,
such as sausage coatings. Algin can also be used to produce nonsticky
icings and glazes. Steiner and McNeely also stated that algin is the
most important ice cream stabilizer in the United States and Great
Britain. Differences among the three gelling agents in stabilization

of ice cream has been discussed by Potter and Williams (52) who

reported algin produced no viscosity change in the ice cream mix and
eliminated the necessity for aging whereas gelatin increased viscosity
and required aging and carrageenan produced such a high initial
viscosity that cooling was difficult. In the pharmaceutical industry
algin has found extensive use as a tablet-disintegrating agent.

Numerous investigators reported algin's use as thickening and stabilizing

agents in.ointment bases, suspensions, and emulsions.

30

Gel Strength Measurements

Various tests have been developed to measure the strength of gels.
Host of them depend upon.measurement of force necessary to erupt the
gel structure for a specified distance or the distance erupted by'a
specified force. In contrast the Exchange Jelometer measures the

natural elasticity of the gel. The measurement of strength of gelling

1mm]
_ J

A“.

agents is standard procedure for their manufacturers. In fact, the
Bloom gelometer test is so universally applied to testing of gelatin

that grades of gelatin are designated as various Bloom values.

‘ ‘Il’g “as.“ M emu

.L"

Bloom gglometer (12, 67)

The Bloom gelometer test measures the weight necessary to force a
12.7 mm. round plunger h mm. into a gel which has been prepared under
standardized conditions. Depending upon the grade of gelatin either a
6.66 or a 12.5 per cent solution is prepared and held at 10°C for 17
hours before testing. It is generally accepted that results of a 6.66
per cent concentration are expressed as blooms and those of a 12.5 per
cent concentration as double blooms. values obtained from.ge1atin

samples range from 0 to slightly over 300 grams and each gram.constitutes
a bloom.

Boucher Jelly tester (38)

The Boucher test measures the force in milliliters of water
required to make a 5 mm. depression by a plunger 13 mm. in diameter*into
a standard gel. The 5 per cent gelatin solution is held at 10 t 1°C
for 16 to 18 hours. This test is performed within two minutes after the
gelatin gel is removed from the constant temperature bath. A force of

31

one milliliter of water is designated a 1 Jellogram. The full nomal
range extends from 1+ to 500 jellograms. To equate the Boucher value
to Bloom values the following formulas are used:

Bloom (6.66%) = Boucher x 2/3 + 18

Bloom (12.5%) = Boucher x 7/3 + 146

Terr-Baker Joly tester (37)

F ‘

The Terr-Baker Jelly tester applies pressure to a plunger of known
area, which is resting on the surface of a standard gel. The pressure

is read at the instant the gel breaks. In preparation of the gel its

1..— e*—_ e——ae t-‘24135
'- ' ’J. n. ‘ ' ’
I I

‘

.

surface is covered with a light film of mineral oil to prevent sldn
formation. Following aging, the oil is removed and the tester's
plunger is situated over the gel. Pressure applied by a flow of water
is controlled so the manometer column rises 60 cm. per minute. The
manometer is read when the gel breaks. Tests are made in triplicate and
averaged and gel strength is reported as the height (in centimeters)

reached by the liquid in the manometer at the gel's breaking point, for

a given concentration.

Nchs penetrometer (37)

This test measures the time required for a plunger of a given weight
to cut into the gel to a specified depth. A standard gel is prepared
and following aging the top l/h—inch layer of gel is removed. The
plunger of the Fuchs penetrometer is adjusted so that it rests on the
top surface of prepared gel. A weight is imposed on the plunger which
is held in a true vertical position. The plunger itself is a sharpened

hollow metal tube that is highly polished. The plunger is released and

32

time, in seconds, required for the plunger to cut into the gel to a
certain depth is noted. This depth is determined by markings on the

rod or shaft affixed to the plunger. Time required to reach two different
depths is noted for each test.

Exchange jelly132§tgg (16)

The Exchange jelly tester measures the amount of natural elasticity
which a gel possesses. This is accomplished by pouring a gel to a
standard depth of 3.125 inches and carefully inverting the gel onto the
instrument which is fitted with a microscrew whose one complete revolution
lowers the screw 0.03125 inches or 1 per cent of the original height.

Thus by adjusting the screw so the tip just touches the released jelly
per cent sag can be determined directly. This test is unique in that it
does not rupture the jelly and does not strain it beyond its normal

elastic limit. Reproducibility of the test is considered good.

Recording gel tester (34)

This test is a mechanized modification of the Sears method. In
this test a device lowers at a slow uniform rate a gel containing an
embedded disc which is attached by a cord to a dynamometer capable of
measuring the desired rate of force. As the gel is slowly lowered, the
dynamometer reacts upward with a continuously increasing force on the
disc until the yield point of the gel is reached. (The dynamometer-
recorder mechanism of the Corn Industries Viscometer can be adapted to
record this force.) The load can be read in gmpcm. from the dynamometer
or can be converted into grams. The reproducibility'of the test is good;
the average variation in tests of replicable gels did not exceed 1 5 per

cent of the mean yield point.

J7

‘ttt‘M‘fl-lfi'unpaflj—i afi’fl

PROCEDURE

Three types of gelling agents were arbitrarily selected for this study:
acid-processed. pure. unflavored gelatin with a bloom value of 220: carra-
GOGDlnsl and algin preparation.2 These products are recommended by their
manufacturers for use as efficient gelling agents in.milk-type desserts.

Preliminary Investigation

The amounts of carrageenan and of algin preparation required to
produce gel strength equivalent to that of pure gelatin in a whole milk-
cornstarch system were determined through preliminary study.

The milk-cornstarch system consisted of 9116 milliliters (32 ounces)
of reconstituted milk, prepared from 127.6 grams of whole milk solids

[Emma 412:3. ”am".u.u ....5. W
. ‘3
5

and 887 milliliters (30 ounces) of no to 50°C tap water. and 13.5 grams of
cornstarch. Previous investigation indicated that the addition of lb
grams of pure gelatin produced desirable gel consistency for this system.
Varying amounts of carrageenan and of algin preparation were tried until
each of these agents produced a gel comparable to the product obtained
with 1a grams of gelatin. A Precision Penstrometer (Arthur H. Thomas Co.)
with lSO-gram load cone attachment was used to establish equivalent gel
strength among products.

For test samples prepared with gelatin or with carrageenan 829
milliliters (28 ounces) of milk was placed in a double boiler and heated
to 80°C. In the preparation of the gelatin samples the gelatin was
hydrated in 58.5 milliliters (2 ounces) of cold milk and dissolved

over hot water. The cornstarch was dispersed manually in the remaining

 

Hype 10 Carrageenan manufactured by Marine Colloids, Inc”
Chicago 5, Illinois.

2l‘iargel. a mixture of algin and calcium carbonate. manufactured by
Kelco Compaw. Chicago 6. Illinois.

33

 

 

—~ _.=-—+i__._:7 _ —

 

3“

58.5 milliliters (2 ounces) of cold milk. The two mixtures were com-

bined, blended, and added to the heated milk. For the carrageenan

samples the cornstarch and carrageenan were dry-bl ended manually,
dispersed by the gradual addition of 117 milliliters (1+ ounces) of cold
milk, and then added to the 80°C milk.

The procedure used for the algin preparation samples differed
slightly. Preliminary trials indicated the algin preparation could be
dispersed more efficiently in hot milk than in cold. Therefore, all of
the milk was heated to 75°C. The algin preparation and cornstarch were

dry-blended manually, sprinkled on the surface of the hot milk, and

 

incorporated with a French whip.
All mixtures resulting from the addition of cornstarch and gelling

agent were held at 77t1°C for fifteen minutes with controlled inter-

mittent stirring. At the end of each cooking period samples were poured

into coded 5-ounce pyrex custard cups to a designated depth, covered

with Saran wrap, and refrigerated at 3 to 6°C for 20 to 2b hours before

penetrometer measurements were taken.
From this investigation it was found that 2.5 grams of carrageenan

or 12 grams of algin preparation produced gel strength equivalent to 1h
grams of pure gelatin in the milk-cornstarch system studied. Penetrometer
values for the six replications for the three gelling agents and the

analysis of variance for these values appear in the Appendix.
If the weight of the gelatin required is considered unity, 0.179

times as much carrageenan or 0.857 times as much algin preparation may

be substituted to produce equivalent gel strength in the milk-cornstarch

system described.

 

35

Basic Formula

The basic formula was developed through preliminary study of products
made from selected milk-type dessert formulas in which pure gelatin was
used for the gelling agent. Only formulas in which whole egg and corn-
starch constituted a part of the thickening effect were considered.

The basic fox-mils consisted of constant proportions of whole milk

solids, whole egg, cornstarch, salt, and water:

 

W M 5
Whole milk solids 510.1; grams
Whole ease l$6.0 grams
Cornstarch 5h,o grams
Salt 6.0 grams
Water 3781+.o milliliters (128.0 ounces)

Formula modification

This basic formula was modified by the addition of 56 grams of pure
gelatin for Series 1, 10 grams of carrageenan for Series 2, and 1&8 grams
of algin preparation for Series 3. The amounts for carrageenan and for
algin preparation were based on the proportional weight of gelatin re-
quired by these agents to produce comparable gel strength as determined
by preliminary study.

Each series was further modified by the type and concentration of
sweetener added: (a) 275 grams and 735 grams of dry sucrose, based on
20 and 1+0 per cent of the total weight of the modified formula exclusive
of water, and (b) 9.1? gram and 214.5 grams of dry calcium cyclamate,

based on the standard sucrose-calcium cyclamate sweetness equivalent for

 

 

 

 

 

36

the sucrose concentrations selected for the study (31). A control for
each gelling agent was also prepared without sweetener.

In the experimental design presented in Table l, the concentrations
of sweeteners for Series 1, 2, and 3 are designated as A, B, C, D, and
E for the control, 20 per cent sucrose, 1&0 per cent sucrose, calcium
cyclamate equivalent to 20 per cent sucrose, and calcium cyclamate
equivalent to #0 per cent sucrose, respectively. PrOportions of in-

gredients for the fifteen experimental treatments are presented in the
Appendix. I

Table 1. Design of experiment.

IW . w. mmivmim

W
Sweetening Agent

Type and Concentration Series 1 Series 2 Series 3
Gelatin Carrageenan Algin Preparation

 

 

A. Control X X X
B. Sucrose -- 20% x X X
C. Sucrose -- ”0% x x x
D. Ca. cycle. = 20% Sucrose X X X
E. Ca. cycla. =- uoat Sucrose X x x

 

Ingredient Procurement

Where possible, the materials used in this studv were obtained from
common lots and, unless otherwise noted, were kept in dry storage at

room temperature.

 

 

37

......Ba c foam W

whole milk was spray-dried by the Michigan State University Dairy,

 

stored in closed polyethylene bags at -20°C until approximately a week
before its use, at which time it was transferred to refrigerator storage
at 3 to 6°C.

Fresh eggs were obtained from the same flock of White Leghorn hens
at the Michigan State University Poultry Farm. The eggs were mechanically
blended, packed in covered plastic-coated containers, quick-frozen at
-bO°C for 1&8 hours, and stored at -20°C until needed.

The cornstarch and salt were obtained from the Michigan State Univer-
sity Food Stores and were stored in their original fiber containers.

Cold water, in which the natural hardness had not been altered w
chemical means, was used in this stew. A standard chemical test1 was
used to determine the degree of hardness of the water used in each

replication.

Gelling agents
The gelatin was obtained from the Michigan State University Food

Stores and stored in its original fiber container with metal top.
Carrageenan and algin preparation were obtained from Marine Colloids, Inc.
and Kelco Comparw, respectively. Both products were stored in closed
polyetlwlene bags in their original cardboard drums.

 

1A Model 69 Kit, Each Chemical Compalv, Ames, Iowa, was used
to test for water hardness. The author gratefully acknowledges the
assistance of Angela Honey, Research Technician, Michigan State
University Dairy Plant, in the determination of water hardness for

thi‘ study.

 

 

 

38

Sweetening _a_g_e_nts
Superfine sucrose was obtained from the Michigan State University

Food Stores and stored in closed polyetlwlene bags in airtight metal
containers. The entire lot of calcium Sucaryl1 was supplied by the
Abbott Laboratories and was stored in its original brown-glass container.

Batch Size

All modifications of the basic formula yielded approximately one
gallon of custard. Preliminary work with both quart and gallon batches
showed no significant difference in gel strength as measumd by a precision
penstrometer for a given series at a particular type and concentration of
sweetener. In order to present findings which might be helpful to
institutional users as well as homemakers, gallon batches were prepared
throughout the study. Four replications of each treatment were prepared.

Prepreparation of Ingredients

mole dried milk, sufficient for one day's preparation, was weighed
on a torsion balance with a ltd-kilogram capacity, reconstituted with
no to 50°C water, stored in a 5-gallon milk can, and refrigerated at 3
to 6°C for 1+8 hours prior to use. The frozen eggs were defrosted for
1&8 hours in a refrigerator at 3 to 6"C and held at room temperature 3
hours prior to use.

Each day's preparation consisted of three batches of custard
representing one replication of each gelling agent at one level of
sweetener. All ingredients were weighed or measured on the day of
preparation. The sucrose, whole egg, cornstarch, and salt were weighed

1Abbott laboratories' registered name for cyclsmate.

 

39

on a torsion balance with a “.5-kilogran capacity whereas the gelling
agents and calcium cyclamate were weighed on a torsion balance with a
2.0-kilogram capacity. To facilitate removal and to minimise handling
losses the gelling agents and the calcium cyclaumte were weighed on
glazed black weighing paper and transferred with the aid of a mrrow
rubber spatula. lbs fluid milk as well as the water used for recon-
stitution were masured in 500- and 2000-cubic centimeter graduated

enamel pitchers.

Cooking Process

Irradiately preceding the cooking of each replication, the relative
humidity was determined from the difference in dry- and wet-bulb temper-
atures read on a Tyeos Husddiguide.

A ten-quart Groen Steam Kettle, Model TDB, was used in the
preparation of all products tested. Steps in the cooking procedures for
Series 1, 2, and 3 were kept as similar as feasible and are presented in
Table 2. Differences among dispersion methods for the selected gelling
agents, as established through preliminary trials, necessitated slight
procedural variations. hid cooking temperatures of 7h°C for the
control samples and for those made with both concentrations of calcium
cyclamate, and 80°C for the 1&0 per cent sucrose samples were established
through preliminary study of the effect of sucrose and calcium cyclamate
on the coagulation temperature of the egg protein in the basic fomula.
The and cooking temperature for the 20 per cent sucrose samples was
arbitrarily set at 77°C, half way between the temperature established for

the control and for the 1+0 per cent sucrose samples.

{H

 

4 L «HIE Hf”. a»

 

 

. .3933? gages no edge.”
.33 you new Henna—co you 0.1K. «.5. 53.3: “ON you 02R. .3825 *3 you 0.8 350a 5000 an
.3... .82... a 05... .335... 800 05....3» 05 g. a.

 

oge Hadodnaooo

5d. p.58 as. 33.0.»...
3 03.2.... 3.68.. 0.5... .n
0.8 no use a. .800. 09. “as
38 e. As an... ...:s 3.0.6

.9525: Hsnoaosooo

5? $58 05 0820.30

3 033...... 23...... 85... .n
no.8 do 0... a. use... 05 as
38 «a A... :8 :3: 520.6

.wcdhuavs Henoansooo

59 £58. 0.8 03301...
3 .0332?» 83.3.. H53... .n
mean no use we .833 use #3....
300 no ...”... awn 59 Euro

 

.85 09.8.3 .00. 03.808 :85 3.8.3 .00. 03.20... :35 00.8.3 .00. 3.80... ..
85.5.3»
#834835 .822»... 5.5 .0523. 9.33.. .055... “E33.
.3... 3 you 0.3.... ... 3... 1.35 0059380 50.. .5: ....35 0.580.... 5.: .5...
83.3.. 0:395. .88.... 2 .80 0.8K as 3... 2.3 ma .8. ?E a. 39. 83
0c. .2... 0.2 no ..3 so can .8. .3... 0.8 3 0.00. in... .5 fie- 0.8 3 0.00.
8.35....» 835. 0.053.»... m no.8 5 08:8 8.8.2.3.. ~ .30 5. 08:8 3.8.0.8 n
.5238 0.5830 5.:
and. 38 do 4.. 8:338 05 and. 38 «o .d.
in 0. 83.0... .3080 B 8. 5 0.32.30 a...3.a£n.§0
.3sdunokfie compound“. was .33....038 .Ssfidonnns con: 303308
can: 39.323 5.533 can: 332? .53.ng 2333 has no 39850 as
has no 03.3.6 and £9.33 he no 00803 65. £83» Jase .aousaufioo £333 aon
.68 Jean 5.: 33.3.5.0 .58 .38 :3: .8083 .26 0.58.... 05 in. 38
839.88.. 50d. 08.03.. A... 3.802.... 02.0%.. .d. 8. flu. 03.30.. 53.0 m
.338. 5.30 580 $0.3 .333. 3.30 .380 3.73 .33... .330 580 5.73
5 0.2. 3 03...... ..E 833 5 0.8 3 03a... .4... 8.5 S 0.8 3 03.... ..d. :93
.3... 32... 033338... AS... 3...: 33388... as 39.: 33333... H
838...... «WW. 28.8 .538 .5... ~30
m 03.8. m 03.28 a union

 

’41

Throughout the heating and cooking periods time-temperature relation-
ships were recorded on a Pfinneapolis-Honeywell Tym 153 Electronik Multi-
point Recorder. Three themocouple leads, taped together to tom an
equilateral triangle measuring approximately l-inch per side, was
centrally positioned in the cooking mass in the Green Steam Kettle. The
purpose of the triple readings was twofold: (a) to give three readings
during each 96-second interval throughout the heating periods (i.e.,
throughout the heating of the milk and the heating of the entire mixture
after the addition of the eggs) in order to assure exact end points, and

(b) to serve as a check on the accuracy of the thermocouple leads them-

 

selves during the constant-temperature cooking period.

Throughout the preparation all dry-blending, dispersing, and stirring
were done manually with a French whip. During the 15-minute cooking
period stirring was controlled so that the mixture was stirred for two
minutes and then allowed to rest for two minutes. This intermittent
stirring ended with a l-minute rest period. All timing was done with

a stop watch.
Preparation of Samples

As soon as the custard reached the designated and temperature, the
cooked mixture was poured through a medium-tine, wire-mosh household
strainer directly into a calibrated container for measurement of batch
depth. In calibrating this container the investigator determined the
container depth in millimeters for volumes ranging from 150 to 190 ounces
at Z-ounce intervals. A table was constructed from these data for the

conversion of mass depth to mass volume.

is quickly as possible, 12 portions of the cooked custard were
poured into coded, 5-ounce pyrex custard cups to a measured depth of
l 3/1b inches and individually covered with Saran wrap secured with a
rubber band. This handling procedure required approximately 15 nimtes.

All samples were refrigerated at 3 to 6°C for 19 to 20 hours before
objective evaluation.

Objective Measurements

01 the day following preparation, objective tests were made to
determine the gel strength, measured both as the ability to resist
penetration and as the ability to hold a rigid shape; syneresis; and
:18. All samples were taken directly from the refrigerator and the Saran

wrap removed. The custard was loosened carefully with a thin, flexible,
l-inch stainless steel spatula.

mtration

Gel strength, as measured by resistance to penetration by a falling
force, was determined by a Precision Universal Puntroneter with a 5-
second penetration for a lSO-gran load cone attachment. This polished,
balanced, brass cone had an elongated sharpened tip. The ISO-gran load,
which meets the A. S. ‘1‘. M. stewards, consisted of 102.5 grams and
h7.5 grams for the cone and the shaft, respectively.

The prepared sample was placed on the leveled platfom of the
pmetroneter so that the tip of the cone was centered over the custard.
With the penetroneter dial set at zero, the cone and shaft assembly was
lowered manually until the tip of the cone just touched the surface of
the custard. This assenbly was then allowed to fall free for a period

 

43

of five seconds and the amount of penetration recorded to the nearest 0.1
millimeter. Figure 1 shows the measurement of penetration after the
release of the cone as well as the equipment used in this test.

Three samples from each replication were tested and the measurements

averaged for the penetrometer value for that replication.

m 2223-. 9.9.:

In order to compare the firmness of custards, measurements of the
height of the inverted sample before and after a specified time interval
were needed. The apparatus shown in Figure 2 was developed to minimize
damage to the gel structure of the sample during testing and to facilitate

Wm“‘“m7

the collection of such data.

The glass surface, on which the sample was to be inverted, was
positioned level with the zero-point of the ruler mounted at the left
of the apparatus. The knurled vertical bar, mounted at the right of the
apparatus, paradtted adjustment of the height of the horizontal bar.
Both the base of the apparatus and the horizontal bar were leveled
periodically throughout the stub.

The loosened custard was inverted on the glass surface of the
apparatus and the horizontal bar lowered until it Just touched the
top of the custard as illustrated in Figure 2. After the initial height
of the sample was recorded to the nearest 1/32 inch, the horizontal bar
was raised so that it no longer touched the custard and the sample was
allowed to stand undisturbed at room temperature for 15 minutes. At the
end of this period the horizontal bar was lowered until it touched the
sample and the height was recorded.

.2328 sea... 3.3:: .533. .38». 88 sob-o3
need we issues- aauaen hen egg .N one»: go eeeeden nevus 839383 means-set .H 98»:

 

“5

Three samples from each replication were tested in this manner.
The per cent sag for each sample was calculated from the difference

between readings divided by the initial inverted height. These per-

centages were averaged to determine the per cent sag for the replication.

Mmsis

The method of Miller et al (#2) was used to determine the weight of
drainage of the custards. The equipment required for this test is shown
in Figure 3.

 

The jellied custard was inverted on fine wire screening (15 wires
per inch) which had been placed over a petri dish of Imam weight.

The
assembly was imediately covered with a stainless steel bowl to prevent

evaporation and allowed to stand 30 minutes. At the end of this period I

the wire screening, containing the custard, was removed. The weight of
the drainage, recorded to the nearest 0.01 gram, was equal to the differ-
ence between the weight of the petri dish before and after testing.

Drainage weights of three samples from each replication were averaged
to determine the value for the replication.

pH

Hydrogen ion concentrations were determined for triplicate samples
of raw egg slurries on the day of preparation and for triplicate samples
of jellied custard slurries on the day of objective evaluation as well as

for duplicate samples of the distilled water used in the preparation of
them.

 

 

323-8 eta... coon-5.. gird. none 3333.38 «is... 8.5.5 new no... venison .n 262

      

nae, . J'uwv ...... .
C... . .

I.

47

The egg slurry was prepared by blending manually l5 milliliters of
defrosted whole egg with 60 nulliliters of distilled water. Meaty-five
grams of the Jellied custard was blended manually with enough distilled
water to bring the total volume to 75 milliliters. All samples for the
pH detersinations were used at room temperature (22 to 28°C) and were
tested on a Beckman Zeromatic pH Meter with a glass and a saturated

calomel electrode.
Analysis of the Data

The data were analyzed according to procedures recommended by the
statistician of the Michigan Agricultural mperiment Station. Analyses
of variance were used to evaluate differences attributable to treatments
for penetration, per cent sag, and syneresis. Significant differences
among treatments were evaluated through use of the Studentised range

table.1

 

lDuncan, D. Multiple F test. Journal of Biometric Society
2: 3-1}, March, 1955.

' “ImmKA—‘Kiifi ~' 11

i-‘

RESULTS AND DISCUSSION

This study was directed primarily toward the objective measurement
of gel strength and syneresis of Jellied custards prepared with three
gelling agents and two concentrations of two types of sweeteners. The
treatment variables were fifteen in number and consisted of all possible
combinations of gelling agents and sweetener concentrations as well as
a control for each gelling agent prepared without sweetener.

Control of techniques used in the preparation of the samples was as
complete as possible. In addition, data relative to water hardness,
relative humidity of the laboratory during preparation, time and temper-
ature of refrigerated storage, pH of raw egg and Jellied custard samples,
and batch yield were collected. Tine-temperature relationships during
cooking were recorded. Variations in these data were noted and considered
in the interpretation of the findings of the study.

Water Hardness and fivsical Factors

Among treatments the mean hardness of water used for reconstituting
the milk solids varied from 299.3 to 312.1 parts per million. Mean
values per treatment for relative laboratory humidity and time and
temperature of refrigerated storage, based on four replications, ranged
from 50.0 to 6M2 for relative humidity and 19.3 to 19.6 hours of storage
at 3.3 to ltd-WC. These data show only minimal variation among treatments
for each factor and are presented in the Appendix.

 

 

“9

PH

Irrespective of the type and concentration of sweetener used, the
pH ranges of Jellied custards prepared with pure gelatin, carrageenan,
and algin preparation were 6.1+ to 6.9. 6.6 to 7.1, and 6.9 to 7.3.
respectively. The pH ranges for individual treatments are reported in
the Appendix. All samples were considered neutral although, within each
gelling agent series, custard samples sweetened with calcium cyclamate
exhibited slightly lower pH values than the control samples and those
sweetened with sucrose.

Idscn and Braswell (36) reported 9.1 as the isoelectric point of
acid-processed gelatin. Boedtker and Doty (11) stated that gelatin gels
formed at the isoelectric point in the absence of salts are weak: however
if sufficient salts are present or if the pH is more than one unit away
from the isoelectric point, weak gels are no longer formed. Since the
gelatin custard females for this study contained a quantity of electro-
lytes and the pH of all samples was below 7.0, it seemed likely that pH
did not affect the gel strength of these samples. According to their
processors (2, 58), carrageenan gels are relatively unaffected by pH
unless the solutions are extremely acidic and alginic acid gels are un-
affected within a pH range of ’4.5 to 12. In view of the findings
reported by these workers, it was concluded that pH of the mixture did
not affect the gelling strength of the selected gelling agents.

Batch Yield

Mean batch yield for treatment, sweetener conglomerate averages, and

per cent volume increase, based on control batch yield, are reported in

 

50

Table 3. Average per cent volume increases for samples prepared with 20
per cent sucrose, ho per cent sucrose, calcium cyclamate = 20 per cent
sucrose, and calcium cyclamate 2 ho per cent sucrose were 5.55, 11.51,

2.85, and 2.10, respectively.

Table 3. Treatment means and sweetener conglomerate averages for batch

yield of Jellied custard.

 

 

 

 

mm
Algin Sweetener
sweetening Agent W .Arszaza...
Type and V01. V01. V01. Vol. Vol. Vol. Vol. Vol.
Concentration Inc. Inc. Inc. Inc.
0t. { 0t. 1 0t. { at. %
Control I0.91a 14.92 10.9“ 11.92
209: Sucrose 5.23 6.52 5.20 5.69 5.16 0.15 5.20 5.55
“0% Sucmse 5052 12.32 5on8 11038 5a“? 10073 50” 11051
Ca.cyc1a.=20$suc. 5.08 3.116 5.06 2.85 5.05 2.23 5.06 2.85
5.03 2,21. 5.08 2.83 5.03 2.10

Ca.cyc1n.=u0$s:ac. ‘1.97 1.22

aBased upon four replications.

Analysis of variance of batch yield, presented in Table h, showed
significant difference attributable to sweetener concentration, at the
l per cent level of probability. In a comparison of conglomerate averages
of batch size for concentrations of sweetener, differences were established
as follows: #0 per cent sucrose-sweetened custard volume ) volumes of
custards made with all other sweeteners. Twonty per cent sucrose-
sweetened custard volume was greater than custard volumes of non-sweetened
and the higher concentration of calcium cyclamate-sweetened samples.
There was no significant difference, 1 per cent level of probability,
between batch yields of custards sweetened with both concentrations of
calcium cyclamate and non-sweetened custards and between batch yields

of 20 per cent sucrose-sweetened custards and custards sweetened with the

51

lower concentration of calcium cyclamate. Inasmuch as differences in
volume affect the dilution of the gelling agent, it is conceivable that
differences in gel strength may be due, in part, to batch yield.

Table 1+. Analysis of variance for batch yield of Jellied custards.

 

Source of Degrees of Sun of Hean
Variance Freedom Squares Squares
Total 10 0.5850

Gelling Agents 2 0.0000 0.0000
Sweeteners 1+ 0. 57“]. 0.1035"
Error 8 0.0109 0.0014

 

"Significant at 1 per cent level of probability.

with the exception of two treatments, gelatin or carrageenan in
combination with calcium cyclamate = M sucrose, the orderly relationship
between weight of sweetener and batch yield appeared to account for
volume increase. However, when the mean batch yields of samples made with
combinations of gelatin or carrageenan with both concentrations of calcium
cyclamate were compared, the relationship between weight of sweetener and
batch yield was reversed. Although this reversal of volume is less pro-
ncunced for carrageenan samples than for gelatin samples, this finding
suggests that the higher concentration of calcium cyclamate may have
affected the gelling capacity of these agents.

Tim—Tamerature Relationships Daring Cooking

The cooking curves for each treatment were divided into three
periods: the heating curve of the milk, the 15-minute holding period

igmw m ‘17 cram]
I" r
.' d

52

at 77t1°c after the addition of gelling agent and sweetener, and the

heating period after addition of the egg-milk mixture.

ma 21m 93. as:

The heating curves of milk for all treatments showed only minimal
variation. The average heating times for both the gelatin and carrageenan
series, heated to 80°C, was 9.0 minutes and for the algin preparation .1...
series, heated to 75°C, average heating time was 8.3 minutes. The rate
of heating was controlled so approximately 5 pounds of pressure were
maintained on the lO-quart Green Steam Kettle. The thermostat was set
at 200°? until the milk reached a temperature of 60 °C for the gelatin and

 

carrageenan series and 50°C for the algin preparation series, and then
lowered to 170 °F.

__t_em__ume- mm @2122? me engage-22:11.12

The time-temperature curves for the 15-minute holding period at
773°C after the addition of gelling agent and sweetener exhibited
greater variation. Each graph in Figure 4 presents the mean time-
temperature relationships for three gelling agents at one type and con-
centration of sweetener. Steam kettle temperature was regulated between
170°? and 180°F to maintain the custard mass at ”11°C.

Although gelling agents presented time-temperature patterns which
appeared similar for all sweetener concentrations, the greatest variation
occurred within the 110 per cent sucrose series. All treatments exhibited
a drop in temperature upon the addition of the gelling agent-sweetener
mixture. This rank order of temperature decrease was: carrageenan series

> gelatin series > algin preparation series. These differences

53

 

 

°C

 

 

   
   

      
 

I I I I T I I I
80 -
78 - - ~
-.. __ ' o—".
__ \ /e——e,’0 e e\\.’_.—-s--e% _
/ ' °

 

 

 

76 / -«
e
c ’ ~
CONTROL
__ Temp. \/ d
Drop
726 _____ 4—1 1 1 I 1 l 1 1 L 1 1 l 1 I 1 1 1
24 Sec 0 2 4 6 8 IO I2 I4 I6 I8

Minutes Holding Time

 

 

 

 

 

 

 

 

 

 

°C
I 1*
\\ I, 20% SUCROSE J
72~Temp. \./ _.
Drop
{_______JTII111111111111111_+
24 Sec. 0 2 4 .6 8 _ IO. l2 I4 I6 I8
°C MInuIes HoldIng Tlme
I I
40% SUCROSE "
72_Temp. \ / ..
_ \/
{______f I 1 1 1 1 I 1 L I 1 1 I 1 1 I 1 L1
24 Sec, 6 2 4 6 8 IO l2 I4 I6 I8

Minutes Holding Time

Figure 4. Mean time-temperature relationships for three gelling
agents with two concentrations of two types of sweet-
eners and a control during the 15-minute holding period.

 

 

H PURE GELATIN
°-—* CARRAGEENAN

H ALGIN PREPARATION

@ 6) Indicates addition of gelling and sweetening agents

 

   

   
  

 

 

 

 

    

 

 

 

I
.1
.“.\ / _

s.___./
CALCIUM CYCLAMATE 4
74 20°/o SUCROSE -1
72 v I 1 L 1 L I 1 1 1 I 1 I I L I I J
24 Sec. 0 2 4 6 8 IO I2 l4 l6 l8
Minutes Holding Time
°C

I
800 1
73 I
76 _I
I \ [I CALCIUM CYCLAMATE ‘
74 “ Temp. \ z 40% SUCROSE ‘
' Drop X -
724::____JI I I I I 1 I I L 1 1 1 1 I 1 1 L 7
24 Sec. 0 2 4 6 8 IO I2 l4 l6 l8

Minules Holding Time

Figure 4. (Continued)

 

55

in degree of temperature drOp were attributable to specific techniques

used for incorporating gelling agents.

Gelatin tine-aggram relationshig. f'l'he gelatin series showed a
temperature drop of approximately 5°C after gelling agent-sweetener
addition followed by an innediate rise in temperature which peaked
between 2 and 5 minutes except for M per cent sucrose which peaked
between7and9ninutes. This peakwas followedbyaprogressive
temperature drop with the last portion of the holding period exhibiting
a fairly constant temperature. It appears probable from this pattern
that the swelling of gelatin and cornstarch occurs during the last half
of the holding period.

Carrageenan tin-tegperature relationships. Curves for the carrageenan
custard samples showed a tuperature decrease of 6.5% followed by a
rise in temperature which peaked between it and 7 minutes. We peak
temperature was lower than peak temperatures or both gelatin and algin
preparation samples. Following this , the temperature dropped slightly
and then remained fairly constant. The slower rise in temperature nay
indicate the swelling or carrageenan occurs soon after addition of the
gelling agent-sweetener mixture and. as a result, the temperature of
the custard lease remains fairly constant. Furthermore. the initial
addition of a cooler mixture, as shown by the increased drop in temper-
ature, may also influence the rate of temperature rise.

Akin preparation tine-temperature relationships, Time—temerature

patterns for the algin preparation series except those sweetened with
#0 per cent sucrose exhibited a slight drop of 0.2°C followed by a rise

 

56

in temperature which peaked at approximately 2 minutes. This peak was
followed by a steady decrease in temperature which ended about 8 minutes
later, remained fairly constant, and finally rose just prior to the end
of the holding period. This curve appears to indicate that swelling of
algin preparation occurred shortly after its addition and the reaction
may be more endothermic than the swelling of the other gelling agents
thus causing the greatest decrease in temperature. The temperature

rise at the end of the holding period may indicate that, under these
conditions, the swelling of algin preparation and cornstarch is completed
after 13 or 1’4 minutes.

Custards gelled with algin preparation and sweetened with 1&0 per cent
sucrose showed a slower rise in temperature which peaked at approximately
12 Inmates followed by a slight decrease in temperature. This curve did
not exhibit a temperature increase at the end of the holding period.

Fasting 23:19.: 311:: W alarm against;

The heating curves of the mixture after the addition of the egg-milk
mixture varied only as the end temperatures varied. The addition of
this mixture caused a 6 to 7°C drop in temperature and the average
heating times for end points of 7h, 77, and 80°C were 3.2, n.2, and 5.?
minutes, respectively. The rate of heating was controlled to maintain
5 pounds of pressure with a thermostatic setting of 185°F.

Time-temperature relationships for the 15-minute holding period
and for the heating after the addition of the egg-milk mixture show
variations in the amount of heat to which the gelling agents were
exposed. Gelatin, in solution, undergoes degradation under the influence
of heat, especially at extremes of the pH scale. In a study of heat

57

degradation of gelatin prepared from omhide, Amos (3) reported the

breakdown of gelatin is slowest at neutrality and is independent of con-
centration. The investigator's results show a 2 per cent solution
heated for 2 hours at 85°C at neutrality lost slightly over 1/5 of its
original gelling power. The processor (58) reported carrageenan is not
sensitive to heat above pH of 3.5 and at pH 7 can be retorted under
pressure for several hours. Within the limits of this study, no
consistent relationship was found between gel strength and time-

temperature relationships during the cooking process.

Gel Strength and Syneresis Tests

Gel strength was measured both as the ability to resist penetration
and as the ability to hold a rigid shape. Resistance to penetration
was determined by a Precision Universal Penetrometer with a 5-second
penetration for a ISO-gram load cone attaclment. mgidity of the sample
was detemdned as per cent sag calculated from measurements of the
height of free-standing inverted samples before and after a specified
time interval. The results were analysed for effects of gelling agents
and two chemically different sweetening agents: sucrose, a non—reducing
disaccharide classified as a non-electrolyte, and calcium cyclamate,

a strong electrolyte which is 90 per cent ionized in solution. The
weight of drainage due to syneresis was determined for a 30-minute
period with controlled evaporation. Throughout the discussion of both
gel strength tests and the test for syneresis jellied custards prepared
without sweetener, 20 per cent sucrose, #0 per cent sucrose, calcium

cyclamate = 20 per cent sucrose, and calcium cyclamate = '40 per cent

58

sucrose will be referred to as sweetener A, B, C, D, and B, respectively.

frustration
Mean penetration readings, based on four replications per treatment,

and conglomerate averages for three gelling agents and five concentrations
of sweetener are surmrized in Table 5. The original penetrometer readings
are presented in the Appendix.

Table 5. Smary of penetroaeter values for Jellied custard: treatment

means and conglomerate averages for gelling and sweetening
agents (millimeters).

 

 

 

 

 

Sweet-
Sweet- W wine we“
ening Pure Algin Agent
“Silt Gelatin Carrageenan Progration Ave. 5% If
A 27.1i8c 31.5u 26.u8 28.1»9 Treatment 0.70 0.91;
B 27.12 30.79 26.09 28.00
c 27.72 31.16 25.41» 28.11 Sweetening
D 27.34 33.07 29.87 30.09 Agent 0.1m 0.9+
E 25.69 33.35 33.97 31.00
Ave. 27.07 31.98 28.37 Agent 0.31 0.152

aSignificant Studentized range values for 2 consecutive averages.
bGelling agent average.

cBased on four replications.

Analysis of variance of these data revealed significant differences
in gel strength, at the l per cent level of probability, attributable to
treatments. The Studentized range test was utilized to sort out signi-
ficant gel strength differences due to gelling agents, sweetening agents,
and individual treatments. The rank order of differences are presented
in Table 6.

 

59

Table 6. Mean squares and rank order of significant differences for
penetration of Jellied custard.

 

 

Source of Mean Significant Differencesa
Variance D. F. Square 1% level Additional at 5% level
Penetration 11+ 35.32" 1 > 3 > 2

B c A ) D > E B c A

E1>I31131fg=61

82 CZ A2) D2 1:2 82 0 A2

 

 

A3 83 03) D3) E3

 

f; ‘1) ‘2 ‘3) A1
83) 81) 82
03) C1) 02
D1) D3) 132

E1) 732 E

 

“Significant at l per cent level of probability.

aSignificantly greater than those that follow. Treatments are
listed in ascending averages. Underlining denotes no significant dif-
ference.

Key: Pure gelatin conglomerate average
Carrageenan conglomerate average
Algin preparation conglomerate average
Control conglomerate average
20$ sucrose conglomerate average
sucrose conglomerate average
Ca. cyclamate x 20% sucrose conglomerate average

Ca. cyclamate 8 ”Of sucrose conglomerate average
1519191313‘23202‘32323 A38303D333 Treatmentunitave.

WUOtflbUNI-J

b

 

60

Gel strength for gelling and sweeteninggaggnts. Conglomerate averages
for penetration data rank gel strength for custards prepared with three
gelling agents as gelatin > algin preparation >. carrageenan custards,
significant at l per cent level of probability. At the same level of
probability, penetrometer values for conglomerate sweetener averages show
samples made with the following types and concentrations of sweeteners
ranked gel strength as: B = C = A > D > E. Additional significance
at 5 per cent probability indicate that custards prepared with B have

greater gel strength than custards prepared with A.

Gel strength difference! withingelatin series. Samples from the treat.

ment combining gelatin with the highest concentration of calcium cyclamate
were significantly stronger, at the l per cent level of probability, than
samples from treatments combining gelatin with the other type and con-
centrations of sweetener. love (39) noted that below the isoelectric
point of gelatin, cations have more effect than anions. Thus calcium
would have more effect than cyclamate at the pH reported for the gelatin
custards of the present study. These gel strength findings agree

with the findings of Nobel (“8) who stated that calcium strengthens
gelatin gels. The lack of significance for gel strength of samples

with sucrose addition disagrees with the works of Friedman and Shearer
(25) and Advani and Narwani (1). It is likely that the effect of”

sucrose may be offset by the significant increase in custard volume.

Gel stmth differences within carraggenan series. When carrageenan

was used as the gelling agent, non-sweetened and sucrose-sweetened

custards had significantly higher gel strength than cyclamateasweetened

61

custards. The B-custard euthibited greater gel strength than the A-
sweetened custard at the 5 per cent level of probability. The increased
gel strength of samples made with 20 per cent sucrose supports the theory
of Tressler and Lemon (68) who preposed that the presence of solutes in
colloidal solutions of carrageenan compete with the colloidal micelles
for water. Dilution of gelling agent due to the increase in batch yield
may explain why gel strength increased significantly only for the lower
concentration of sucrose. The effect of calcium cyclamate on carrageenan
gels has not been reported in the literature. Possibly increased ionic
strength or a specific effect of calcium ions or the large cyclamate anions
contributes to the results noted in this study.

Gel strength differences within algin preparation. For samples prepared
with algin preparation, the A custard was significantly stronger, l per
cent level of probability, than C custard. At this same level the A, B,
and C «stands had greater gel strength than D custard. All the foregoing
custards were stronger than the custard prepared with the higher con-
centration of cyclamate. Scott (57) reported that complexes formed w
polyanions such as alginic acid with cationic detergents were soluble

in salt solutions at concentrations characteristic to the polyanion
polymer and that 0.33 N. potassium chloride or 0.30 1'. magnesium chloride
had sufficient ionic strength to maintain 70 per cent of the alginate in
solution. Although the normalities of calcium cyclamate concentrations
used in the study under discussion were approximately 0.02 and 0.05,
respectively, and would not appreciably affect ionic strength of the
custard formula, calcium cyclamate addition appeared to reduce gel
strength.

62

Gel 31.35321: differences within sweetener series.‘ Custards prepared with
the three gelling agents for A, B, and C sweeteners ranked gel strength
as follows 3 algin preparation ) gelatin > carrageenan custard. For
samples prepared with D sweetener, the gel strength of the algin
preparation and gelatin custards was reversed. The rank order of gel
strength for Iii-sweetened custards was gelatin ) algin preparation >

carrageenan samples.

The inverted samples in Figure 5, representing 15 treatments, do
not illustrate as great a variation in gel strength as is indicated by
significant differences in mean penetrometer measurements. Differences
in inverted heights are readily observed in the cyclamate series of
custards. As can be seen in Table 5. page 58, samples prepared with
calcium cyclamate :- 1&0 per cent sucrose exhibited the greatest variation
in millimeters of penetration for treatment means, ranging from 25.69 to
33.97 m.

£6.15 ....cent as

Original per cent sag data appear in the Appendix. From this
table it can be seen that sag percentages for the treatment combining
algin preparation and sweetener B were at least 5 times greater than sag
percentages of all other treatments. This treatment was sipificantly
different from all others and these values were not included in the
analysis of variance. Mean per cent sag values for fourteen treatments,
based on four replications per treatment, and conglomerate averages for

three gelling agents and five concentrations of sweetener are summarized
in Tabb 7e

63

GELLING AGENTS

SWEETENER Gelatin Carrageenan Algin Preparation
CONC.

Control

 

20% Sucrose

 

h0% Sucrose

Ca. cycla. =
20% Sucrose

Ca. cycla. =
h0$ Sucrose

 

Figure 5. Initial inverted heights of jellied custards
prepared with three gelling agents and five
concentrations of sweetener.

 

Table 7. Sumner-y of per cent sag values for Jellied custard: treat-
ment means and conglomerate averages for gelling and sweet—

 

 

 

 

ening agents.
Siteet-
SVeet- W suing .
onins Pure Alain Agent __§.§..B..L7___¥_
gent Gelatin Carrggceenan Preparation Ave. # 5 l
A 2.81° 2.99 0.87 2.22 Treatment 0.66 0.88
B 2.79 3.68 1.88 2.79
D 1e92 5e98 3032 Be?“ Agent 0.38 0e51-
E 1.72 ‘ 5.11 -- 3.91
Awe 2.112 “.18 1.85 Agent 0e29 0.39

 

———~

“Significant Studentized range values for 2 consecutive averages.
bGelling agent averages.
cBased on four replications.

Analysis of variance of these data revealed significant differences
in rigidity among treatments, at the l per cent level of probability.
The Studentised range test was used to establish significant rigidity
differences due to gelling agents, sweetening agents, and individual
treatments. The rank order of these differences is presented in Table 8.

Elsi-(lit; differences 1'0}: 5911125 and sweeteW. The conglomerate
averages of gelling agents rank custard rigidity as algin preparation )
gelatin ) carrageenan custard. In comparison with penetration findings,
algin preparation and gelatin custards have reversed positions. This
reversal may result from the omission of data for one algin preparation
treatment.

Conglomerate averages of sweetening agents indicate the non-
sweetened samples are significantly more rigid than the other types and

concentrations of sweeteners, at a probability of l per cent. At the

 

65

 

 

 

 

 

 

 

 

Table 8. Mean squares and rank order of significant differences for
per cent sag of Jellied custard.
Source of mean Significant Differencesa
Variance D. 1?. Square 1% level Additional at 5% level
Per cent Sag l3b 113.09“ 32/ 11> 2
A>fl g E D 2.50242
31 D1 B1 A1 Cl E1131> B1*“1‘31
A:a> B2> C2152132 C232) D2
A 0:133) D3 A3) C; a:
A3>A1A2
133131132
03) 01> c2
a>s>e
F032

 

“Significant at l per cent level of probability.

aSignificantly greater than those that follow.
underlining denotes no significant

listed in

ascending averages.

difference.
b'Algin preparationp--Ca. cyclamate a “0% sucrose was not included.

1 Pure gelatin conglomerate average

2 Carrageenan conglomerate average

3 Algin preparation conglomerate average
A Control conglomerate average

B 20% sucrose conglomerate average

C sucrose conglomerate average

D Ca. ”313108“ 3 20%
E Ca. cyclamate I hofi

Treatments are

sucrose conglomerate average
sucrose conglomerate average

A1 31 C1 D1 E1; A2 £2 02 D2 E2; A3 B3 03 D3 E3 Treatment unit ave.

66

5 per cent level, samples containing 20 and 1&0 per cent sucrose are

significantly more rigid than samples containing the two concentrations
of calciun cyclamate.

errences for__gglati‘n series. Winn gelatin was used as the
gelling agent, samples prepared with sweetener E were significantly more
rigid, at the l per cent level of probability, than samples prepared with
sweeteners B, A, and 0. Within this series mean sag percentages of E

and D custards as well as D, B, A, and C custards were not significantly
different. However, custards containing either concentration of cyclanate

were more rigid than non-sweetened and sucrose-sweetened custards at

 

5 per cent level of probability. Since rigidity and gel strength are
closely related, these . results are also in accord with the findings of
NO“). (1+8) e

Efgidity differences for carrageenan series. Samples made with
carrageenan an! various sweetener concentrations rank in rigidity,
significant at l per cent probability, as A > B > C = E but > D and
E = D-custards. At the 5 per cent probability, custards made with the
higher concentration of calcium cyclanate were more rigid than custards
prepared with the lower concentration of calcium cyclamate. These
findings disagree with Tressler and lemon's (68) theory that the
presence of solutes decrease free water thus allowing less liquid for
the gelling agent to entrain. Elasticity has been noted in the
nannfacturer' s bulletin (53) as characteristic for sucrose-carrageenan

gels.

6?

Bi t diffe ces for a re tion. . Significant differences
in rigidity for custards prepared with algin preparation show samples
sweetened with cyolamate had lower rigidity than non-sweetemd and sucrose-
sweetened samples. Custards prepared with the higher concentration of
calcium cyclamate formed a very tender gel structure. Possibly the
calcium alginate is dissolved by the salt concentration as has been
reported by Scott (5?); however in view of the normalities of calcium
cyclamate used in this study, this explanation appears questionable.

These findings evoke taro important questions: When present in relatively
small concentrations, does calcium cyclamate affect the gel structure of
alginates? What percentage of soluble alginate must be reached before

the gel formation of the system is adversely affected?

l-‘tigiditz differences within sweetener series. Non-sweetened custards
ranked in rigidity as algin preparation ) gelatin a caman samples.
Algin preparation and gelatin custards sweetened with 20 per cent sucrose
as well as gelatin and carrageenan samples sweetened with 20 per cent
sucrose showed no significant difference in rigidity. Forty per cent
sucrose-sweetened custards eldxibited the rank order of algin preparation
> gelatin > carrageenan samples for rigidity. When cyclamate = 20 per
cent sucrose was the sweetening agent, rigidity was greatest for gelatin
custards and lowest for carrageenan samples. Gelatin custards sweetened
with the higher level of calcium cyclsmate were more rigid than carra-
geenan custards sweetened with the higher level of calcium cyclamate.
Figure 5, page 63, illustrates the initial inverted height of
samples representing the 15 treatments. From this , the per cent sag of

custards containing cYclamate can be observed. Tenderness of gel

 

68

structure for the custard.representing the treatment combining of algin

preparation with sweetener B may be noted from the visible degree of sag.

§IE££2§E£
Table 9 summarizes mean drainage values, based on four replications

per treatment, and conglomerate averages for three gelling agents and

five concentrations of sweetener. Original syneresis values are reported

Table 9. Summary of drainage values for Jellied custard: treatment.
means and conglomerate averages for gelling and sweetening
agents (grams). ‘

 

 

 

 

Sweet-
Sweot- ...—W ening
ening Pure Algin Agent a
{Agent Gelatin Carrggeenan Preparation ‘éve. 52 :2
A 0.08° 1.00 0.50 0.53 Treatment 0.65 0.87
B 0.0? 0.75 0.3b 0.39
C 00"‘5 1.01 0.36 0e60 Sweeten-
D 0.12 2.21 0020 0.84 111g Agent 0032 00M
E 0.11 5.27 0.33 1.90
G. Ab Gelling
Ave. 0.16 2.05 0.3“ Agent 0.29 0.39

 

aSignificant Studentized range values for 2 consecutive averages.
bGelling agent averages.

cBased on four replications.

Analysis of variance of drainage due to syneresis revealed that
there were significant differences attributable to treatment, at the
1 per cent level of probability. Significant drainage differences due
to gelling agents, sweetening agents, and individual treatments were
found by use of the Studentized range test. The rank order of these data

is presented in Table 10.

69

Table 10. Mean squares and rank order of significant differences for
drainage of Jellied custard.

 

Source of mean Significant Differencesa
Variance D. F. Square 1% level Additional at 5% level
Syneresis 1b 7.21“ 2 > 2 1

E)DCAB DCAB

 

E2>92>C2A232
D2)D3D1

132>Ezn1

 

”Significant at l per cent level of probability.

aSignificantlygreater than those that follow. Treatments are
listed in descending averages. Underlining denotes no significant
difference.

Key: 1 Pure gelatin conglomerate average
2 Carrageenan conglomerate average
3 Algin preparatiOn conglomerate average
A Control conglomerate average
B 20%Tsucrose conglomerate average
C 40% sucrose conglomerate average
D Ca. cyclamate = 20% sucrose conglomerate average
E Ca. cyclamate = #0% sucrose conglomerate average

AlBlchlElg AZBZCZDZEZ; 58303D3E3Treatmentmfitave.

Drainage differences for gelgggg and sweetegigg agggts. Drainage due to

syneresis was significantly greater for samples with carrageenan used
as the gelling agent than for samples with gelatin or algin preparation
used as the gelling agents. Conglomerate averages for sweeteners show
that custards containing sweetener E exhibited a larger‘weight of

 

70

drainage than all others, significant at l per cent probability. At 5 per
cent probability custards sweetened with the lower concentration of calcium

cyclamate had a larger weight of drainage than custards sweetened with 20

per cent sucrose.

Drainage differences within gelatin and algin preparation series, No

significant differences for drainage were found between custards gelled
with gelatin or algin preparation.

Drainage differences within carrageenan series. For samples gelled by

carrageenan, the weight of drainage varied with sweetener addition,

 

significant at 1 per cent probability: E > D > C = A = B samples. E'—

Drainage differences within sweetener series. Sucrose- and non-sweetened
custards exhibited no significant differences in the weight of drainage
due to syneresis when combined with a particular gelling agent. For
both concentrations of cyclamate the amount of drainage from custards
prepared with carrageenan was significantly greater, 1 per cent
probability, than custards made with algin preparation or gelatin. The
weight of drainage from custards sweetened with cyclamate and gelled

with algin preparation or gelatin was not significantly different.
Texture of Non-sweetened Jellied Custard

Texture differences of non-sweetened Jellied custard prepared with
gelatin, carrageenan, and algin preparation were subjectively compared

both by mouth-feel and by appearance of the cut sample. The texture of
B‘mples, noted as mouth-feel by the investigator, may be described as

71.

follows: gelatin - smooth, clings to the roof of the mouth; carrageenan --
mctremely smooth, airy, melts in the mouth; and algin preparation -- pasty,
:rough, almost gritty.

Differences in cut surface appearance of non-sweetened custards are
illustrated in Figure 6. Texture of the gelatin custard is neither
extremely smooth nor coarse. Smll air bubbles are apparent in the other-
wise smooth carrageenan sample. The custard containing algin preparation
exhibits a coarse, pebbly texture. The gelatin and the carrageenan
custards display a bubbly surface whereas the surface of the algin

preparation sample is quite smooth. E

 

72

 

 

.mpcewm mcflnaem swans. spa: sandman fineness panama. Bumpemsmncoc mo meommanm £6

ZOHH<m<mmmm ZHOA¢ z<zmmo<mm<o

.0 shaman

 

ZHBjmo

SUMMARY AND CONCLUSIONS

The purpose of this investigation was to compare the effects of
two concentrations of sucrose and two concentrations of calcium cyolamate
upon the gel strength of selected gelling agents in the preparation of
Jellied custard. The gelling agents, arbitrarily chosen from products
recomended by their respective manufacturers for use in silk-type desserts,
were acid-processed, pure, unflavored gelatin with a bloom value of 220;
carrageenan;1 and algin preparation.2

The basic experimental formula consisted of constant proportions

of whole milk solids, whole egg, cornstarch, salt, and water. This

 

formula was modified for series 1, 2, and 3 by the addition of pure
gelatin, carrageenan, and algin preparation in the gram-ratio of 1.00 x
0.179 3 0.857, respectively. This ratio was established through pre-
liminary laboratory investigation of equivalent gel strength among agents
for a standard milkacornstarch system. Each series was further modified
by the type and concentration of sweetener added: 20 and no per cent
sucrose, based on total weight of the modified formula exclusive of
water; dry calcium cyclamate in amounts required for sweetness comparable
to the sucrose concentrations selected for the study; and a control
Without sweetener for each gelling agent.

All products were cooked in a 10-quart Groen Steam Kettle. Pre-

liminary preparation, cooking procedure, and sample preparation were

h‘

1Type 10 Carrageenan manufactured by Marine Colloids, Inc.,
Chicago 5, n1.

Znarzel, a mixture of algin and calcium carbonate, manufactured
by K9100 Company, Chicago 6, Ill.

73

7n

kept as similar as feasible. Differences among suitable dispersion methods
for the selected gelling agents necessitated slight procedural variations.
All samples were refrigerated at 3.3 to h.h°c for 19.3 to 19.6 hours
before objective evaluation.

Data relative to water*hardness, relative humidity of the laboratory
during preparation, time and temperature of refrigerated storage, pH of
raw egg and Jellied custard samples, and batch yield were collected. Tims- r“
temperature relationships during cooking were recorded on a Minneapolis-
Honeywell Multipoint Recorder.

 

Objective tests were made to determine gel strength, measured both

as the ability to resist penetration and as the ability to hold a rigid

 

shape, and syneresis. Resistance to penetration was determined by a
Precision Universal Penetrometer with a 5-second penetration for a 150-
gram.load cone attachment. ‘Measurements for the calculation of per cent
sag were taken to compare the rigidity of custards. Per cent sag was
calculated from the difference between the inverted sample height before
and after a 15-minute free-standing period divided by the initial inverted
sample height determination. Drainage due to syneresis of a free-standing
inverted sample was measured as the weight of the drainage resulting
from a 30-minute standing period with controlled evaporation.

‘Water hardness, physical factors, and pH data indicated only
minimal variation. Variance resulting from the addition of types and
concentrations of sweeteners was found to be significant for batch yield.
The orderly relationship between weight of sweetener and batch yield
appeared to account for volume increases of all custards sweetened with

sucrose, all custards sweetened with the lower concentration of calcium

75

cyclamate, and algin preparation custards sweetened with the higher con-
centration of calcium cyclamate. Mean batch yields for gelatin or
carrageenan samples sweetened with the higher concentration of calcium
cyclamate exhibited smaller volumes than samples made with these gelling
agents and sweetened with the lower concentration of calcimn cyclamate.
This reversal suggests the higher cyclamate concentration may have affected
the gelling capacity of these two agents. Furthermore, since differences
in total weight of ingredients used affect the dilution of the gelling
agent, it is conceivable that gel strength differences apparent in this
study may be due, in part, to the variation in batch yield.

Heating curves of milk and of the custard after the addition of the
egg-milk mixture showed only slight variation among treatments. Within
the limits of the study, time-temperature relationships for the 15-minute
holding period at 77'_'_'l°C established consistent patterns for each gelling
agent at all concentrations of sweetener. Time-temperamre cooking
curves also presented thermal eXposure during the holding period for
each treatment. No consistent relationship was found between gel strength
or the sample and time-temperature relationships during cooking.

Significant differences for gel strength were established from both
penetration and per cent sag data. Custards gelled with algin preparation
01‘ gelatin exhibited greater gel strength than custards gelled with
carrageenan. The rank order for gelatin and algin preparation custards
Varied with the type and concentration of sweetener present. ancrose-
a"veetened custards gelled with algin preparation seemed to have greater

gel strength than sucrose-sweetened custards gelled with gelatin whereas
an inverse gel strength relationship occurmd for cyclamate-sweetened
”simples gelled with these two agents.

76

Per cent sag data showed rigidity of carrageenan gels decreased with
sucrose addition and this effect was greater as the concentration of
sucrose increased. Penetration data, however, did not support these
findings.

The addition of dry calcium cyclamate seemed to increase gel strength
for gelatin custards while it decreased gel strength for both carrageenan .
and algin preparation custards. This effect was increased as the con- '
centration of calcium cyclamate was increased. Custards gelled with
algin preparation and sweetened with the higher concentration of calcium

 

cyclanate exhibited the largest decrease in rigidity.

IE"

Variance in the weight of drainage due to syneresis among treatments
was found to be significant. Syneresis was evident only for custards
gelled with carrageenan and the weight of drainage appeared to be
enhanced by the addition of dry calcium cyclamate.

Custard texture for non-sweetened samples gelled with gelatin,
carrageenan, and algin preparation can be described as moderately smooth,
extremely smooth and airy, and coarse and pebbly, respectively. Gelatin
and carrageenan custards displayed a bubbly surface whereas the surface
of algin preparation custards was quite smooth.

Although the jellied custards were not evaluated for flavor, all
custards except those sweetened with the higher concentration of calcium
cyclamate were considered acceptable by the investigator. Custards
prepared with calcium cyclamate = 1+0 per cent sucrose had a bitter
fiftertaste.

The findings of this limited study indicate custard gel strength
is a function of both gelling agent and type and concentration of

sweetener used. Evaluation of these findings evoked certain questions
which suggest the need for studv in these related areas: (1) a study in
which the amount of gelling agent is equilibrated for increased volume
contributed by the sweetening agent to determine whether dilution of the
gelling agent has contributed significantly to the findings of the
current stuck; (2) sodium cyclamate should be substituted for calcium
cyclamate to determine whether the effect of dry calcium cyclamate on
gel strength was due to calcium or cyclamate ions; and (3) varied amounts:
of gelling agents should be used in custards sweetened with calcium
cyclamate to determine whether the effect of calcium cyclamate on gel

 

strength could be overcome.
Further investigations are warranted to establish whether syneresis

is inherent in the milk-type carrageenan gel or whether formula modifi-

cations can overcome this drainage.

£3.

:3.

JLC).

JJL.

31:3.

14

LITERATURE CITED

Advani, R. D. and Narwani, C. S. Reactions of sugars with gelatin.
Jour. Ind. Chem. Soc. 27: 615-618. 1950.

Algin at work. Kelco Company, Chicago, Illinois. 1952.

Ames,‘W. H. Heat degradation of gelatin. Jour. Soc. Chem.
Ind. 66: 279-284. 1947.

Ames, W3 H. The manufacture of hide glue and gelatin. Jour. Soc.
leather Trade Chem. 333 "'07. 19149.

Ames,‘wz M. The preparation of gelatin. II. Methods of shortening
the soaking period. Jour. Soc. Chem. Ind. 63: 2314-241. 19%.

Andlng, Ce Es, Jr. Gelatin. In Kirk, R. Ea ‘m Othmerg De (filters).
The encyclopedia of chemical technology. Vol. 7. p. lh5-153.
New Yerk, Interscience. 1951.

Astbury, W. T. Structure of alginic acid. Nature 155: 667-668.
1995.

Bayley, S. T. X-ray and infrared studies on carrageenin. Biochem.
et Biophys. Acta 17: 194-205. 1955.

Belle, J., Riese, H. C. A. and Vinograd, J. R. mechanism of
gelation; influence of certain electrolytes on the melting
points of gels of gelatins and chemically modified gelatins.
Jour. Phys. Chem. 60: 1299-1306. 1956.

Black, w. A. P., Cornhill, w. J. and Mar, E. T. The properties
of algal chemicals. 1. The evaluation of common British brown
marine algae as a source of alginates. Jour. Sci. Food Agr.

3: 51‘2‘5500 1952e

Boedtker, H. and Doty, P. A study of gelatin molecules, aggregates,
and gels. Jour. Phys. Chem. 58: 968-983. 195“.

Bronson, W. F. Technology and utilization of gelatin. Food Tech.
5: 55-58. 1950.

Buchanan, J., Percival, E. E. and Percival, E. G. V. The poly-
saccharides of carragheen moss (Chrondus crispus). I. The

linkage of the D-galactose residues and the ethereal sulphate.
Joure Chem. SOC. 1%3: 51.58. 19430

Chanda, S. K., Hirst, E. L., Partival, E. G. V. and Ross, A. G.

The structure of alginic acid. II. Jour. Chem. Soc. 1952:
1833-1837. 1952.

78

2115-»

16-

3L1?N-

18-

19.

20-

21-

13:3.

21+.

2315.

26.

137’.

28.

79

Cook, W. 3., Rose, R. C. and Colvin, J. R. Macromolecular properties
of carrageenin. Biochem. et Biophys. Acta 7: 601. 1951.

Cox, R. E. and Higby, R. H. A better way to determine the Jelling
power of pectins. Food Ind. 16: hue-uu2,5os.507. l9hh.

Cretcher, L. H. and Nelson, W. L. A new type of acid carbohydrate
from seaweed. Science 67: 537-538. 1928.

Dahlberg, A. C., Carpenter, D. C. and Hening, J. C. Grading of
commercial gelatin and its use in manufacture of ice cream.

Ind. Eng. Chem. 20: 516-526. 1928.

Eldridge, J. E. and Ferry, J. D. Studies of the cross-linking
process in gelatin gels. III. Dependence of melting point
on concentration and molecular weight. Jour. Phys. Chem.

58: 992-996. 195%.
F.D.A. names 182 safe additives. Food Eng. 32: 81-82. 1960.

Perry, J. D. mechanical properties of substances of high molecular
weight. IV. Rigidities of gelatin gels: dependence on con-
centration, temperature, and molecular weight. Jour. Am.
Chem. SOC. 70: 221414-2299. 191‘8e

Ferry, J. D. Protein gels. In Edsall, J. T. and Bailey, K. (editors).
Advances in protein chemistry. Vol. 4. p. 1-78. New York,
Academic Press Inc. 1948.

Ferry, J. D. and Eldridge, J. E. Studies of the cross-linking
process in gelatin gels. Jour. of Phys. and Colloid Chem.
53: 18h-196. 1949.

Fischer, F. G. and Dorfel, H. The polyuronic acids of brown algae.
(AbatraCt) Chemo Abse 50: 7237s 1957.

IFriedman, L. and Shearer,‘w. N. The effect of non-electrolytes
upon the setting time of gels. Jour. Am. Chem. Soc. 61:
17u9-175l. 1939.

Butch, C. 0. and Metcalf, B. Preparation of irish moss extracts
for use as a Jelling and stabilizing agent in foods. Canad.
Joure R950, Sect. F 23: 273-285. 1%5.

Gibson, K. F. and Rothe, L. B. Algin versatile food improver.
FOOd Else 27("0e 10): 87-89e 1955s

Glam, E. Fe, 60m, P. Fe and MONO“, Pe We EfoCtS of 11'181')
moss extractive (carrageenin) on wheat-flour products.
Cereal Sci. Today 2: 159-162. 1957.

129%.

3C)..

BELA-

322”.

lajL.

1+2:

80

Glahe, E. F., Goldman, P. F. and Anderson, P. W. Row irish moss
extractive improves protein-content foods. Food Eng. 29:
65—67. 1957.

Goring, D. A. I. and Young, G. E. Studies on carrageenin:
comparison of fractions obtained.with potassium.chloride and
by successive extraction at elevated temperatures. Can.
Jour. We 33: “80-14950 19550

Gross, H. M., Abbott Laboratories, North Chicago, Illinois.
Information on calcium cyclamate. (Private communication.)
1960.

Haas, P. and Russell-wells, B. On carrageen (Chrondus 2535225).
IV. The hydrolysis of carrageen musilage. Biochem. Jour.
23: h25-h29. 1929.

g.
I-
4

Hansen, P. H. T. and Whitney, R. M; A quantitative test for
carrageenin ester sulfate in milk products. Jour. of Dairy Sci.
“3 3 175.186 e 1960 e

Hjermstad, E. T. A recording gel tester. Cereal Chem. 32: 200-207.
1955.

Idscn, B. Seaweed colloids: $10 million now and growing fast.
Chem. Week 79(no. 3): 57-80. 1956.

Idscn, B. and Braswell, E. Gelatin. In Hrak, E. MR and Stewart,
G. F. (editors). Advances in food research. Vol. 7. p. 235-338.
New York, Academic Press Inc. 1957.

Kerr, R. W; Chemistry and industry of starch. 2nd ed. New York,
Academic Press Inc. 1950.

Koprowski,‘W. 5. Determination of Jelly strength of glues and
gelatins by the "Boucher” jelly tester. Analyst 76: 732-73“.
1952.

Lowe, B. Experimental cookery from the chemical and physical
standpoint. hth ed. New York, John Wiley and Sons, Inc. 1955.

marshall, S. M. and Orr, A. P. Effect of different ions on gel
stgzngth of red seaweed extractives. Adv. in Chem. 11: 101-103.
19 .

Mechanism of algin gel formation. Kelco Company Publication
CD-301, Chicago, Illinois. 1959.

Miller, G. A., Jones, E. M. and Aldrich, P. J. A comparison of the
gelation properties and palatability of shell eggs, frozen
whole eggs, and whole egg solids in standard baked custard.
Food Res. 2b: 584-59h. 1959.

1&3.

51.

52.

53.

81

Hongar, J. L. and Wassemann, A. Influence of ion exchange on
optical properties, shape, and elasticity of fully-swollen
alginate fibers. Jour. Chem. Soc. 1952: 500-510. 1952.

Morel, J. and Grabar, P.
gelation.

The groupings of gelatin responsible for
(Abstract) Chem. Abs. 1:6: 71149. 1952.

Nelson, W. L. and Cretcher, L. H. The alginic acid from Macromtis

225313“. Joure Am. Chem. SOCe 51: 191k1922. 19290
Nilson, H. W. and lemon, J. M. Metabolic studies with algin and
gelatin. 0.5. Fish and Wildlife Ser. Res. Rept. 1+: 1-9. 1992. p
’1
Nilson, H. W. and Wagner, J. A. Feeding tests with carrageenin.
FOOd ROB. 2h: 235-239e 1959.
Nobel, P. C. The influence of cations on the gelatin gel. III. The

influence on the elasticity. Rec. trav. chim. 71: 639-6b2.

 

1952.
O'Neill, A. N. 3,6-anhydro-D-galactose as a constituent of H- *2
carrageenin. Jour. Am. Chem. Soc. 77: 2837-2839. 1955.

O'Neill, A. N. Derivatives of 14-0- B -D-ga1actopyranosy1-3,6-
anmrdro-D-galactose from H. -carrageenin. Jour. Am. Chem. Soc.
773 632u'6326e 1955s

Ouer, R. A. Sensitivity to kelcoloid.
1949.

Ann. Allergy 7: 681-682,?18.
Potter, F. E. and Williams, D. H. Stabilizers and emulsifiers in
ice cream. Milk Plant Monthly 39(no. a): 76-78. 1950.

Rice, F. A. R. The effect of solvent and temperature on the
viscosity of the polysaccharide of irish moss and the effect

of solvent on its initial gelation. Canad. Jour. Res., Sect.
8 21:: 12-19. 1916.

Richardson, E. G.
293 494-502.

Rose, R. C. Extraction, fractionation, and evaluation of
cmd. Joure Res., Seet. F 283 202-2]2e 1950.

The mechanics of gelation.

Trans. Faraday Soc.
1933.

carrageenin.

R080, Re Ce m COOk, W. H.

The suspending power and viscosity of
carrageenin.

Canad. Jour. Res., Sect. F 27: 323-336. 1999.

Scott, J. E. The solubility of cetylpyridium complexes of biological

polyanions in solutions of salt. Biochem. et Bio s. Acta
10: 1:28.429. 1955. ply

 

58.

59.

60.

61.

62.

63.

65.

66.

67.

68.

69.

70.

71.

72.

73.

82

Seakem extracts technical issue. Marine Colloids, Inc.
(formerly Seaplant Corporation), New York. 1957.

Smith, D. B. The effect of) .. and lot-carrageenins on viscosity of
Milk. Can. Joure TBChe 313 209'2120 ‘19550

Smith, D. B. and Cook,‘W. R. Fractionation of carrageenin. Arch.
Biochem. and Biophys. 458 232-233. 1953.

Smith, D. B.’ O'Neill, A. No and Pbrlin’ A. Se StUdies on the
heterogeneity of carrageenin. Can. Jour. Chem. 33: 1352-1360.
1955.

Smith, F. and Hontgomery, R. The chemistry of plant gums and
mucilages and some related polysaccharides. New Yerk,
Reinhold Publishing Corp. 1959.

Steiner, A. B. and EcNeely,‘W. R. Algin in review. Adv. in Chem.
113 68-82e 195“.

Stoloff, L. Irish moss extractives. Adv. in Chem. 11: 92-100.
195“.

Thiele, H. and Andersen, G. Ionotropic gels of polyuronic acids.
II. Degree of order. (Abstract) Chem. Abs. #9: 15371. 1955.

Thiele, H. and Hallich, K. Capillary structure in ionotrOpic gels.
(Abstract) Chem. Abs. 51: 13520. 1957.

Thomson, A. 0. Laboratory control in gelatin and glue manufacture.
Indus. ChOMiSt 28: 255-258. 1952.

Tressler, D. K. and lemon, J. M. Marine products of commerce.
2nd ed. New York, Reinhold Publishing Corp. 1951.

Tseng, C. K. Phycocolloids: useful seaweed polysaccharides.
In Alexander, J. (editor). Colloid Chemistry. V61. 6.
p. 629-73“. New York, Reinhold Publishing Corp. 19h6.

Tseng, C. K. Seaweed resources of North America and their
utilization. Econ. Botany 1: 69-97. 1997.

'Ward, A. G. Recent advances in gelatin research. Chem. and Ind.
183 502-505. 195“.

Weiser, H. B. Colloid chemistry. 2nd ed. p. 327-335. New York,
John Wiley and Sons, Inc. 19h9.

wooduard, N. Seaweeds as a source of chemicals and stock feed.
Jour. Sci. Food Agr. 2: h77-h87. 1951.

83

APPENDIX

 

 

Table 110

‘Mean penetrcmeter values for gel strength

equilibration (millimeters).

Gelling Agents

 

 

Replication Gelatin Carrageenan Preparation
1 27.20a 26.60 28.17
2 27.147 26.23 27.00
3 29.27 28.00 25.27
a 230h3 25037 25057
5 25.70 2h.63 26.23
6 29.67 25.97 25.93
Average 26.31 26.27 26.36

 

aBased on three readings.

 

 

Table 12. Analysis of variance of mean penetrometer values
for gel strength equilibration.
Source of Degrees of Sums of Mean
Variance Freedom Squares Squares
TOtfll 17 ““059
Gelling agents 2 0.17 0.09
M? 15 ”4.192 2e96

-__.

 

85

econoem mo: u eveseaohu smaoaeo a w oeonosm wow u samemfloho.eeavaeo u o oeoaoem $0: a o
(Immmuosm.mmw - m Hopscoo - a :oasaauaopa cause - m cacoomaauao . N cepmaoo - a ”ace

 

o: --- --- namu --u, o.e imww ewe sown; :.oaw munli
we --- --- ma.m --- o.e an we: seem e.oum n-m
m: --- --- -uu nmn 0.0 em mm: amen 3.0Hm can
we --- --- --- new o.o an we: amen :.oan m-n
m: --- us- an: --- o.w em mm: amen 2.0Hm <um
--- 0H --- n.:~ --- o.e an we: swam e.oam m-~
--- 0H --- as.m --- 6.6 an we: amen a.oam o-~
--- 0H nun --- non o.w an em: amen n.0Hm ocm
--- 0H --- --- new o.w an we: amen e.oan m-~
--- ca --- --- --- 0.6 an ow: amen e.oan «em
--- --- en n.e~ --- o.e an we: swam e.oHn m-H
--- --- en ea.m --- o.e an em: swan 3.6Hn qua
--- --- en --- nae o.e an em: swam 2.6Hn o-H
--- --- on --- new 0.6 an we: seen e.oan m-a
--- -- o.e an we: seem a.o~n «-H

 

 

 

fie". e emails; stress: 33 #3 San
nodvmasnean canoe» save even oeoaosm uHam seamen ammo nouns. medaoe
nawn< unease idem anoho lanoo eHogz. made aces
095m endedeo eHogz undone
‘IhmmmmflmnuamW1

.euuuuso eaaeaon co aoapaumaoua one as ea»: unassuoc Hancoeaaonxu essence: .nH canes

Table 1“. ‘Water hardness, physical factors, and pH for jellied cus-
tard.made with.three gelling agents and two concentrations

of two sweeteners.a

 

 

 

Treat- gzfisf Relative Hours Temp. Raw Jellied
ment ness Humidity Stored Stored Egg Custard
(pm) °c
l-A 312.1 59.0 19.3 3.3 7.197.“ 6.8-6.9
l-B 307.8 62.5 19.3 3.“ 7.1-7.“ 6.8-6.9
1-C 299.3 6“.0 19.3 3.“ 7.1-7.5 6.3-6.9
l-D 303.5 52.0 19.3 3.3 7.197.“ 6.6-6.7
1-E 307.8 63.9 19.“ 3.7 7.197.“| 6.“-6.6
2-A 312.1 5“.8 19.3 1+.“ 7.2-7.5 7.0-7.0
2-B 307.8 61.7 19.“ 3.8 7.1-7.5 7.0-7.0
2-C 299.3 6“.2 19.5 “.2 7.3-7.5 6.9-7.1
2-D 303.5 50.2 19.“ “.0 7.197.“’ 6.8-6.9
2-E 307.8 60.0‘ 19.5 “.0 7.3-7.6 6.6-6.7
3-A 312.1 5“.8 19.5 3.5 7.1-7.3 7.2-7.3
3-B 307.8 62.0 19.“ 3.“ 7.1-7.5 7.2-7.3
3-C 299.3 60.2 19.5 3.5 7.1.7.5 7.2-7.3
3-D 303.5 50.0 19.“ 3.5 7.3-7.5 7.1-7.2
3-E 307.8 59.2 19.6 3.3 7.1-7.5 6.9-7.0
aValues based on four replications per treatment.
Key:l - Pure Gelatin A - Control

B - 20% Sucrose
C - “0% Sucrose
D - Ca. cyclamate a 20% Sucrose
E - Ca. cyclamate = “0% Sucrose

2 - Carrageenan
3 - Algin Preparation

Tabl. 15e

Penetrometer values for jellied custard:

original data,

treatment means, and conglomerate averages for gelling and

sweetening agents (millimeters).

 

 

 

 

 

 

Sweet-
Sweetening Agent Series 1 Series 2 Series 3 ening
Type and Concentration Pure Carrageenan Algin Agent
111 Gelatin ___ Preparation Ave.
A ControI 27e33 31e17 26e67
27.20 31.10 25.70
27.83 32.00 26.57
27e56 31087 26e93
“ban 2?.“8 Blesh 26eu8 28eh9
B 20% Sucrose 26.63 30.77 25.63
27.20 30.23 26.63
27057 aleoj 25053
27.“? 31.13 26.5?
Mean 27.12 30.79 26.09 28.00
c 40% Sucrose 27.30 31.07 2“.80
28.13 31.07 26.00
27.43 31.“? 25.80
28.03 30.63 25.17
Mean 27.72 31.16 25.““ 28.11
D Ca. Cyclamate . 20% Sue. 27.07 32.70 30.93
27.30 33.27 29.77
27.17 33007 29050
27.33 33.23 29.2?
Mean 27.30 33.07 29.87 30.09
E Ca. Cyclamate = “0% Sue. 2“.67 32.97 39.23
26.23 ’ 33.53 33.53
25.73 33-“3 3“.“3
26e13 330“? 33067
mean 25.69 33.35 33.97 31.00
Gelling Agflnt AYOTRgO 27e07 31e98 28e37
Significant Studentized Range Value for 2 Consecutive Averages
evel 1% level
Treatment means 0.70 0.9“
Sweetening agent averages 0.“0 0.5“
Gelling_ggent averages 0.21 0.“2

 

 

Table 16 e

Per cent sag values for Jellied custard:

 

origina1 data,

treatment means, and conglomerate averages for gelling and
sweetening agents.

 

 

 

 

 

 

‘Statistician considered data too large to be included in

 

. .__§sllinz.iasnt_ Sweet-
Sweetening Agent Series 1 Series*2 Series 3 ening
Type and Concentration Pure Carrageenan Algin Agent
..1 Gelatin ‘_fiPreparation Ave.
A Control 3.56 2.77 0.70
2.82 2.82 1.38
2.76 2.82 0.69
2.11 3.56 0.70
Mean 2.81 2.99 0.87 2.22
B 20% Sucrose 2.78 “.27 2.07
2.81 “.18 2.07
2.82 3.51 2.0“
2.76 2.77 1.3“
Mean 2.79 3.68 1.88 2.79
C “0% Sucrose 2.91 “.8“ 0.69
2.8“ “.9“ 1.38
2.76 “.90 1.99
2.88 “.21 1.30
Mean 2e85 “.70 lea“ 2e%
D Ca. cyclamate 8 20% Sue. 2.05 5.7“ “.36
1.“5 6.58 2.70
2.05 5.77 3.“?
2.13 5.8“ 2.7“
Mean 1.92 5.93 3.32 3.7“
E Ca. cyclamate = “0% Sue. 1.36 5.02 31.36a
2.12 5.23 27.5“3
1.36 5.12 3“.31a
2.02 5.07 22.853
mean 1.72 5.11 29.02a 3.“1
Gelling Agent Average 2.“2 “.“9 1.85
‘7‘ Significant Studentized Range Values for Two Consecutive Averages
_1L.1_2_vs.1_
‘ Treatment means 0.88
Sweetening agent averages 0.51
__ Gelling—agent averages 0. 39

 

analysis with remaining figures.

89

Table 17. Drainage values for Jellied custard: original data, treat-
ment means, and conglomerate averages for gelling and sweet-
ening agents (grams).

 

 

 

 

W Sweet-
Sweetening Agent Series 1 Series 2 Series 3 ening
type and Concentration Pure Carrageenan .Algin. Agent
Gelatin Preparation Ave.
A Coutml 0006 1.08 0.“8
0.09 0.99 0.67
0.11 1.02 0.“1
0.05 0.92 0.“5
than 0.08 1.00 00% 0053
B 20% Sucrose 0.0“ 0.82 0.“6
0.05 0067 0053
0.06 0.67 0.17
0.13 0.8“ 0.20
M6811 0.0? 0075 003“ 0039
c “03% Sucrose 0.71 0.93 0.27
0.“3 0.86 0.59
0.25 1.00 0.20
0.39 1.25 0.36
Mean 0.05 1.01 0.36 0.60
D C8. ”ch-la“ 3 20% Sue. 0.20 3e°9 0006
0.10 2.0“ 0.21
0.09 1.38 0.15
0.08 2.33‘ 0.36
Mean 0.12 2.21 0.20 0.8“
E Ca. cyclamate 8 “0% Sue. 0.19 5.11 0.“6
0.09 70a? 0.”?
0.06 “.67 0.26
0.08 3.83 0.13
Mean 0.11 5.27 0.33 1.90
Gelling Agent Average 0.16 2.05 0.3“

 

Significant Studentised Range values for Two Consecutive Averages

Treatment means

Sweetening agent averages

Gelling_§gent averages

 

ev l ev 1
0.65 0.87
0.32 0.““
0.29 0.39

 

 

If..-
H5”:

 

3t"
.“I .
(V

.3??? fl
9., r
I ‘ .‘a
e‘. a
i§‘$z
_; «if.
left"

‘9“!
>Q:!H

HICHIGQN STQTE UNIV. LIBRRRIES

 

I!!!" III lllllll lill ll!“ IUIHII IHII

312 30106 3494