Food product thickened or gelled with carrageenan and glucomannan

What are disclosed are edible materials containing a thickened or gelled phase comprising a mixture or a reaction product of at least one carrageenan and at least one glucomannan, wherein the gelled phase may be either a thermo-irreversible gel or a thermo-reversible gel and the pH of the edible material is below 8.

This invention relates to food products and, especially to a gelling system 
for use in the preparation of gelled or thickened food products. 
A variety of gelling, binding and thickening agents, are used in the food 
and confectionary industries to impart desired textural and aesthetic 
qualities to foodstuffs including, for example, meat loaves, canned pie 
fillings, petfoods, ice cream, yoghurts, formed fruit pieces, etc. 
It is known that glucomannans such as those extracted from the 
Amorphophallus sp. for example A. konjac, when treated with alkalis react 
to form a very tough thermo-irreversible gel. The pH required for this 
gelling reaction is at least 9 and a pH greatly in excess of 9 is 
frequently used. It is widely believed that calcium ions are also 
essential for this process. 
It is also known that gels can be formed using for example pectins and 
seaweed extracts such as alginates and agar. Alginates and pectates 
normally form thermo-irreversible gels in the presence of divalent ions. 
The reaction rate and strength of these thermo-irreversible gels increases 
with decreasing pH. By control of divalent ion availability, which is 
itself pH dependent, a thermo-reversible gel can be produced using 
pectates. 
Certain forms of carrageenan, especially kappa and iota carrageenans, but 
not lambda-carrageenan, can also be used to form gels. These gels are 
thermo-reversible and although carrageenans can form gels at low pH, the 
gels are readily hydrolysed if heated at temperatures in excess of 100 
degrees Centrigrade at pH values below 7. The extent of hydrolysis is very 
pH dependent increasing sharply with decreasing pH. 
It is further known that there is an interaction between kappa carrageenan 
and locust beam gum (carob gum) which results in enhanced viscosity 
development and gelation properties. A mixture of carob gum and 
carrageenan is widely used to provide viscous gravies, in for example 
canned pie fillings, and thermo-reversible gels in for example canned 
petfoods, brawns and table jellies. An additional advantage of the 
interaction is that the carrageenan gel texture is modified to provide 
additional desirable characteristics such as reduced brittleness and 
increased softness. 
In contrast to the thermo-irreversible gels of calcium alginate and calcium 
polypectate, carrageenan/carob gum mixtures cannot be used to provide 
structure in formed products which are to be subjected to heating above 
the melting point of the gel system. Thus, for example the 
carrageenan/carob gum gelling system cannot form the basis of a formed 
chunk in a product which requires to be heated above the melting point of 
the gelling system since the chunk disintegrates on melting of the gel. 
Until now, carob gum has been thought to be unique in its ability to 
enhance the gelling or thickening properties of carrageenan. Although, 
like carob gum, guar gum and tara gum are galactomannans, their 
interaction with carrageenans is considerably less than that of carob gum 
and these polysaccharides are of little use in this context. 
It has been proposed in Japanese published patent application No. 
1978/52648 to produce a gelled seaweed food by blending dissolved or 
colloidal seaweed with dissolved Devils Tongue material (a glucomannan 
containing material). The blend is caused to gel by the normal method for 
gelling glucomannan, namely, the addition of alkali. The gel is a 
thermo-irreversible gel. 
The presence of high alkalinity in food products is generally undesirable 
and accordingly the presence of a thickened or gelled phase which has been 
produced at high pH in most food products is very unacceptable. 
This invention is based on the observation that in complete contrast to the 
teaching of the prior art, glucomannans can be caused to form gels at a pH 
not higher than 8 in a gelling system in which they are present with a 
carrageenan. 
Parent application Ser. No. 138,726 filed Apr. 9, 1980 and now abandoned 
teaches that thermo-irreversible gels can be produced by reacting a 
mixture of at least one glucomannan and at least one carrageenan at a 
temperature of at least 100.degree. C. for a sufficient period of time 
provided that the pH is at least 5 but that in the presence of certain 
foodstuffs, especially meat and other proteinaceous materials the gels 
formed under the same conditions are thermo-reversible. Later filed patent 
application Ser. No. 310,281 filed Oct. 9, 1981 and now abandoned teaches 
that by suitably adjusting the conditions of gel formation 
thermo-irreversible gels can be produced, when the pH of the aqueous phase 
is between 5 and 8, whether or not the temperature is above 100.degree. C. 
and whether or not meats and other proteinaceous materials are present in 
the aqueous phase. More in particular, thermo-irreversible gels can be 
produced using a carrageenan/glucomannan reaction system when the pH is 
between 5 and 8 provided that the heat input is sufficient, even though 
the temperature of the system is not raised above 100.degree. C. and/or 
proteinaceous material of veyetable or animal origin is present. 
Thus the gels which can be formed may be thermo-reversible or 
thermo-irreversible depending on the treatment to which the gelling system 
is subjected. 
While the mechanism of gel formation is not fully understood, the degree of 
gel formation and the type of gel formed appears to be governed, inter 
alia, by pH, the glucomannan and carrageenan content (the "gum" content) 
and the heat input. 
At pH values below 5.0, the glucomannan/carrageenan system always produces 
a thermo-reversible gel. 
It has been observed however that in the presence of certain foodstuffs, 
for example meats and other proteinaceous materials of both vegetable and 
animal origin, the pH below which it is generally impossible to produce 
thermo-irreversible gels seems to be somewhat higher. This may be due to 
the inherent acidity of the proteinaceous materials but it appears that 
generally speaking for the formation of a thermo-irreversible gel in the 
presence of meat and other proteinaceous materials the pH should be at 
least 6.3 to 6.4. The thermo-reversible gels can be formed simply by 
incorporating a mixture of powdered glucomannan and carrageenan in hot 
water or can be formed in complex systems such as sterilised canned meat 
products. For thermo-irreversible gels however the gelling system must be 
subjected to a heat input which is at least equivalent to heating the 
gelling system to a temperature of at least 50.degree. C. for a period of 
up to 16 hours, the particular time needed for gel formation depending 
basically on the temperature, when all other conditions are equal. Under 
the heating conditions normally applied in the heat sterilisation of 
canned food products, for example 110.degree. to 130.degree. C. for 50 to 
60 minutes, a thermo-irreversible gel will normally be formed with a total 
gum content as low as 1% when the pH is between 6.3 and 8. As indicated 
hereinbefore however for thermo-irreversible gel formation it appears to 
be essential that the pH is above 5 but apart from this the heat input can 
be lower, the closer the pH is to 8 and the higher the concentration of 
gellable constituents in the aqueous phase of the system. The higher the 
temperature, of course, the shorter the heating period required to form a 
thermo-irreversible gel. 
Surprisingly, moreover, it has been found that the time to form a 
thermo-irreversible gel can be greatly reduced, when all other factors are 
the same, if the gelling system, having been produced by dissolving the 
ingredients in a hot aqueous phase, is cooled and subjected to an ageing 
process at room temperature before it is reheated to form the gel. 
It has also been found that the presence of certain other ingredients in 
the gelling system affects either the heat input required to form a gel or 
the toughness of the gel obtained for a given heat input. Thus, for 
example the presence of potassium ions in the gelling system produces a 
marked increase in the toughness of the gel, as also does the presence of 
carob gum in addition to the other gum ingredients. 
The invention provides a food product having a pH not higher than 8 
comprising a gelled or thickened aqueous phase containing a mixture or a 
reaction product of at least one gluocomannan and at least one 
carrageenan. 
The invention also provides a process for the production of an edible 
product having a pH between 5 and 8 and having a gelled aqueous phase 
provided by a mixture of at least one glucomannan and at least one 
carrageenan, which comprises subjecting a gellable combination to a 
temperature of at least 50.degree. C. for a period of up to 16 hours such 
as to form a thermo-irreversible gel in the aqueous phase. 
The invention further provides a meat analogue comprising proteinaceous 
material dispersed in and bound together by a thermo-irreversible gelled 
aqueous phase, wherein the gelling system comprised a mixture of at least 
one glucomannan and at least one carrageenan. 
Any carrageenan or carrageenan-type polysaccharide, for example, 
furcellaran is suitable. The carrageenan may be used in a crude form (e.g. 
washed seaweed) or in an alklaine modified form or in the form of the 
conventional carrageenan extracts of commerce. The carrageenan may be any 
form of carrageenan such as lambda, iota or kappa carrageenan or any 
mixture thereof, but the preferred carrageenan types are those containing 
some kappa carrageenan. 
The glucomannans may be used in a purified form or in the crude form. The 
crude form may merely be the ground source of gluocmannan without further 
treatment. Although and glucomannan is suitable, the preferred 
gluocmannans, mainly because they are only ones that are readily 
commercially available, are those that are found in the corms of the 
Amorphophallus genus and in particular in the corms of A. rivieri (Syn A. 
Konjac), A. oncophyllus, A. variabilis, A. bulbifera and A. blumei. 
The preferred ratio of glucomannan to carrageenan is in the range of 20:1 
to 1:20 and the preferred concentration of the combined mixture in the 
aqueous phase is 0.01% to 5%, preferably 0.5 to 5% by weight. 
The product of the invention is an edible material having a pH not higher 
than 8, which is structured, or shaped, or bound, substantially by a gel 
matrix produced from a mixture of glucomannan and carrageenan in the 
aqueous phase. 
The edible material of the invention may be any foodstuff or confectionery 
in which it is desired to have a gelled or thickened phase. As a 
thermo-irreversible gel the food product may comprise, for example a 
gelled chunk which with the addition of flavouring and colourings or other 
similar food materials may be used as a meat analogue and in this form the 
material may have a texture very similar to cooked lung. Preferably, as a 
thermo-irreversible gel, however, the gel serves as a binder for a meat 
analogue comprising meat or other proteinaceous material dispersed in and 
bound together by the gelled aqueous phase. As a thermo-reversible gel the 
edible material may be for example a meat-in-jelly petfood or at very acid 
pH down to about say 3 a thermo-reversible gel may be present in gelled 
deserts and confectionery, especially fruit based products in which the 
fruit acids considerably lower the pH. 
The edible product of this invention may be any foodstuff or confectionery 
in which it is desired to have a structured or shaped form which is 
resistent to structural breakdown upon heating. The gelled foodstuff may 
include flavouring, and colouring ingredients. If desired, humectants and 
fungistats may be included to provide microbiological stability in, for 
example, so-called "semi-moist" foods. A major advantage of the gelling 
system over other polysaccharide gelling systems such as alginates and 
polypectates is that there is no necessity for treatment with divalent or 
polyvalent ions, a process which often imparts a palatability negative to 
the product unless an efficient washing stage is included. 
Another advantage of the gelling system over calcium alginates lies in the 
stability of the glucomannan/carrageenan gels to heating in the presence 
of polyphosphates. Food analogues structured by calcium alginate soften 
considerably when heated in the presence of polyphosphates whereas the 
products of this invention do not. This is particularly useful for meat 
analogues which are to be included in common convenience foods since these 
often contain polyphosphates. 
Yet another advantage of the gelling system used in this invention is that 
it is odourless and flavourless even after severe heat treatment. This is 
in marked contrast to many vegetable protein binders such as the soya, 
cottonseed, and wheat proteins used in commerce. The gelling system of the 
invention does not therefore contribute a palatibility negative to the 
foodstuff in which it is included.

The following Examples illustrate the invention. In the Examples the 
carrageenans were commercially available samples of the type specified and 
the Amorphophallus sp. extract contains approximately 90% glucomannan. 
EXAMPLES 
1. Thermo-reversible gels. 
A petfood product was prepared to the following recipe: 
______________________________________ 
INGREDIENT % by weight 
______________________________________ 
"Meats" Offal Meats 40 
Fibrous Muscle Meat 16 
Hydrated T.V.P. 10 
Condensed Whey 3 
"Gravy" Dye Solutions 0.7 
Water 29.09 
Potassium Chloride 0.5 
Kappa-carrageenan 0.16 
Carob gum (Industrial Grade) 
0.55 
100.00 
______________________________________ 
The gravy was prepared by mixing all the ingredients at room temperature 
using a high shear stirrer. Sufficient alkali was added to the gravy in 
order to maintain a final product pH of 6.2. The gravy was then added to 
the coarsly chopped "meats" and the product was filled into metal cans, 
which were sealed and heat sterilised in a pressure cooker @ 130.degree. 
C. for 60 minutes after which time the cans were immersed in cold water 
for half an hour. The product was examined after 1 day. 
A similar product was prepared but instead of the 0.16% carrageenan and 
0.55% carob gum added to the gravy, 0.11% carrageenan and 0.55% 
glucomannan extracted from Amorphophallus sp. was used. 
Upon examination the products were assessed to be similar in appearance, 
taste and firmness. The product containing flucomannan/carrageenan was 
rated as tougher to cut than the control containing carob gum/carrageenan 
even though the carrageenan level was lower. 
The pH of both products was 6.2. 
Both gels were thermo-reversible each melting at 75.degree. C. and setting 
at 42.degree. C. and 52.degree. C., respectively. 
EXAMPLE 2 
This example demonstrates the greater stability of glucomannan/carrageenan 
solutions to heating at low pH. 
The process of Example 1 was repeated using the following recipe. 
______________________________________ 
CONTROL TEST 
PRODUCT PRODUCT 
INGREDIENT % by weight 
% by weight 
______________________________________ 
Meat Offal Meats 37 37 
Fibrous Muscle Meat 
16 16 
Hydrated T.V.P. 
10 10 
Condensed Whey 6 6 
Gravy Dye Solutions 0.7 0.7 
Water 29.09 29.09 
Potassium Chloride 
0.5 0.5 
Kappa carrageenan 
0.16 0.16 
Carob gum (Industrial 
0.55 -- 
Grade) 
Amorphophallus sp. 
-- 0.55 
extract 
100.00 100.00 
______________________________________ 
The pH of both products was 5.7. 
The control product containing carob gum barely supported its own weight 
and consisted of meats surrounded by low areas of very weak gel slurry and 
a large quantity of free water liquid. This is typical of the degradation 
of this gelling system subjected to high temperatures at relatively low 
pH. 
In contrast the product containing glucomannan was an integral solid meat 
and jelly pack, self supporting and containing areas of clear, soft, tough 
gel without syneresis. 
EXAMPLE 3 
This Example demonstrates the preparation of a "formed" solid which is 
stable to heat in a thermo-irreversible structure using 
carrageenan/glucomannan. 
A 6.8 pH buffer solution was prepared using; 
______________________________________ 
0.4% NaH.sub.2 PO.sub.4 
2H.sub.2 O 
0.44% Na.sub.2 HPO.sub.4 In distilled water 
0.2% KCl 
______________________________________ 
2 parts of kappa carrageenan and 5 parts of Amorphophallus sp. extract were 
dispersed in 1000 parts of the buffer solution ahnd heated to the boil 
with stirring. 
The dispersion was heated in an autoclave at 130.degree. C. for 50 minutes. 
After removal from the autoclave the resulting firm, very tough, solid was 
cut into chunks. The chunks exhibited remarkable resistance to shearing 
forces and had a texture similar to cooked lung. With the addition of 
flavourings and colourings the chunks make an excellent meat analogue. 
The chunks were heat sterilised in water in sealed cans at 130.degree. C. 
for 1 hour. The chunks retained their separate identity demonstrating 
thermo-irreversibility of the gel. 
EXAMPLE 4 
This example demonstrates the use of different carrageenans. 
(a) Use of Iota carrageenan 
The process of Example 1 was repeated using the following recipe: 
______________________________________ 
TEST 
CONTROL PRODUCT PRODUCT 
INGREDIENT % by weight % by weight 
______________________________________ 
Offal Meats 37 37 
Fibrous Meat 7 7 
Hydrated T.V.P. 
26 26 
Dye solutions 
1.5 1.5 
Water 27.4 27.0 
Sodium Chloride 
0.4 0.4 
Calcium Hydroxide 
0.1 0.1 
Iota Carrageenan 
0.6 0.6 
Amorphophallus sp. 
-- 0.4 
extract 
pH 6.1 6.3 
______________________________________ 
The control product containing no glucomannan was barely integral just 
supporting its own weight. The pack readily broke down under slight 
pressure to reveal glossy meat in a viscous gravy. There were small areas 
of a very weak paste-like gel. 
In contrast, the product containing the glucomannan was integral easily 
supporting its own weight. This pack had significant areas of an elastic 
clear glossy gel. 
(b) Use of Lambda Carrageenan 
The process of example 1 was repeated except that: 
In the control product the carrageenan and carob gum were replaced by 0.5% 
Lambda carrageenan and the difference was corrected for adjustment of the 
water content. The pH of the product was 6.6. 
In the test product the carrageenan and carob gum were replaced by 0.5% 
Lambda carrageenan and 0.4% Amorphophallus sp. extract. Again the recipe 
was corrected by adjustment of water content. The pH of the product was 
6.8. 
The control was a non-self supporting meat in gravy product. The gravy was 
viscous, glossy and clear. 
The product containing the glucomannan was firmer and more resistant to 
rupture and had some areas of clear gel. 
EXAMPLE 5 
This example demonstrates the use of different types of glucomannan source. 
Example 1 was repeated with the carrageenan and carob gum replaced by the 
following ingredients: 
In product A, Amorphophallus oncophyllus extract (0.31%) and kappa 
carrageenan (0.32%) were used (pH 6.8). 
In product B, the process and recipe of product A was repeated but 
replacing the 0.31% A. oncophyllus extract by 0.25% A. rivieri extract (pH 
6.7). 
In product C, the process and recipe of product A was repeated but 
replacing the 0.31% A. oncophyllus extract by 0.31% glucomannan from 
Indonesian Amorphophallus sp. extract prepared by the process described in 
Japanese published patent application No. 1979/49346 (pH6.8). 
Examination of the finished products after the day showed that all three 
were virtually identical being integral solid meat and jelly packs, self 
supporting and containing areas of clear, soft, tough gel without 
syneresis. 
EXAMPLE 6 
This example demonstrates the interaction between glucomannan and 
carrageenan to produce thermo-irreversible gels under different pH 
conditions. 
1. Buffer solutions at pH values of 5.5, 6.5, and 7.0 were prepared to the 
following formation: 
______________________________________ 
pH mg Na.sub.2 HPO.sub.4 
mg NaH.sub.2 PO.sub.4 
______________________________________ 
5.5 205 4795 
6.5 1615 3385 
7.0 3090 1910 
______________________________________ 
Each of the above dry salt mixtures was dissolved in 500 ml of distilled 
water. 
Kappa carrageenan was dissolved in each buffer at 80.degree. C. at a 
concentration of 1% w/v. 
Once the carrageenan has dissolved, 1% glucomannan as used in Example 5 
product C is added while mixing with a high shear mixer. 
The solutions were sealed in cans, heat sterilised at 130.degree. C. for 1 
hour, cooled and examined. 
For comparison purposes, the above exercise was repeated replacing the two 
gums by 1% of the glucomannan along in one case and by 1% kappa 
carrageenan alone in the second case. 
The results obtained are noted below. 
______________________________________ 
1% kappa- 
carrageenan 
1% kappa- and 1% 
carrageenan 1% glucomannan 
glucomannan 
______________________________________ 
pH 5.5 Thin solution 
Slightly Tough, 
viscous slightly 
solution brittle gel; 
similar 
texture to 
alginate gels 
pH 6.5 Very weak, Viscous Tough brittle 
brittle gel; 
solution gel 
Excess 
syneresis 
7.0 Weak, brittle 
Viscous Tough brittle 
gel; some solution; some 
gel 
syneresis very weak gel 
pieces present 
______________________________________ 
The gels produced using 1% glucomannan in conjunction with 1% kappa 
carrageenan were cut into chunks and canned in water. These were then 
re-processed at 130.degree. C. for 1 hour. 
After re-processing, the chunks remained integral and discrete. 
EXAMPLE 7 
This example relates to a chocolate jellied-milk. 
______________________________________ 
RECIPE TEST PRODUCT CONTROL 
______________________________________ 
Calcium Sulphate 
0.50 g 0.50 g 
Potassium citrate 
1.25 g 1.25 g 
Sugar 77.00 g 77.00 g 
Chocolate powder 
10.00 g 10.00 g 
Low methoxyl pectin 
2.00 g 2.00 g 
(DE of 30-50%) 
Potassium-sensitive 
0.62 g 0.62 g 
carrageenan 
Calcium-sensitive 
1.19 g 1.19 g 
carrageenan 
Glucomannan as used 
0.95 g -- 
in Example 5 
product C 
Carob gum (Industrial 
-- 0.95 g 
Grade) 
______________________________________ 
The above dry powders were weighed out and mixed together. 
570 ml of milk was then heated to 85.degree. C. and the dry powders were 
whisked in using an egg-whisk. 
The resulting mixture was then allowed to set at room temperature for 2-3 
hours, to form the product. 
The recipe allows by the addition of preservatives, flavours and food-grade 
colours although these are not included in the recipe as given. 
The control product, containing carob gum was a neutral (pH 6.1) 
chocolate-flavoured dessert gel that cut cleanly with a spoon. There was 
some syneresis. The product containing glucomannan had a pH of 5.97 and a 
similar texture but showed no syneresis. 
EXAMPLE 8 
This example relates to a fruit-flavoured dessert gel and demonstrates the 
use of glucomannans in low pH food systems. 
______________________________________ 
RECIPE TEST PRODUCT CONTROL 
______________________________________ 
Calcium sulphate 
0.5 g 0.5 g 
Adipic acid 2.5 g 2.5 g 
Potassium citrate 
1.25 g 1.25 g 
Sugar 77.00 g 77.00 g 
Low methoxyl pectin 
2.00 g 2.00 g 
(DE 30-50%) 
Potassium-sensitive 
0.62 g 0.62 g 
carrageenan 
Calcium-sensitive 
1.19 g 1.19 g 
carrageenan 
Glucomannan as used 
0.95 g -- 
in Example 5 
product C 
Carob gum (Industrial 
-- 0.95 g 
Grade) 
______________________________________ 
The above powders were weighed out and mixed together. 
570 ml of pineapple juice was heated to 85.degree. C. and the dry powders 
incorporated with an egg whisk. 
The resulting mixture was then allowed to set for 2-3 hours at room 
temperature to form the product. 
The formation allows for the addition of preservatives, flavours and 
food-grade colours as required although these are not included in the 
recipe above. 
The control product containing carob gum was an acidic (pH 3.3) 
pineapple-flavoured dessert gel that cut cleanly with a spoon. There was 
some syneresis. The product containing glucomannan had a pH of 3.3 and a 
similar texture but showed no syneresis. 
EXAMPLE 9 
This example demonstrates the preparation of a typical thermally 
irreversible meat analogue product. The meat analogue product was prepared 
using the following recipe: 
______________________________________ 
INGREDIENTS % by Weight 
______________________________________ 
Meats Fibrous Muscle Meats 
27.3 
Offal Meats 16.2 
Ground Bone 6.5 
Gravy Amorphophallus sp. extract 
1.5 
Kappa - carrageenan 
1.0 
Water 47.5 
100.00 
______________________________________ 
The meats were coarsely chopped and then mixed in the proportions given 
above, before being minced through a 5 mm screen. The minced meats were 
then added to the correct proportion of water and the whole was then 
heated to 90.degree. C. with occasional stirring. When the mixture had 
attained a temperature of 90.degree. C. the gravy powders were added, 
using the proportions given above, while the mixture was thoroughly 
macerated using a high-shear stirrer. During the addition of the gravy 
powders the temperature of the mixture was kept in the range 
90.degree.-95.degree. C. When the gravy powders were evenly dispersed, the 
mixture was poured into an aluminium tray, covered and left to cool. When 
cool, the product was processed in a pressure cooker after which time the 
product was cooled. 
When cool, the product was found to be tough, with a meaty appearance and 
could be cut cleanly into chunks with little or no fines being produced. 
The product resembled cooked lung. 
The pH of the product was 6.4. The product was found to be 
thermally-irreversible when assessed in the following manner: 
The product was cut into cubes of side-length about 25 mm and 250 g of the 
cubes were placed in a metal can. The can was then filled with water and 
sealed before being processed in a pressure cooker at 130.degree. C. for 
one hour. The can was then cooled by immersion in cold, running water. 
When cool, the can was opened and the contents assessed. 
Thermo-irreversibility was confirmed since the chunks were still tough and 
discrete with clean surfaces after this treatment. Thermally-reversible 
chunks fuse together under the test conditions forming a single lump. 
The structural integrity of the analogue is entirely due to the glucomannan 
and carrageenan present, since any contribution from the meats was 
destroyed by the 90.degree. C. pre-heat treatment. 
EXAMPLE 10 
This example demonstrates the advantage of ageing the analogue mix prior to 
the heat forming process to improve the analogue toughness. 
______________________________________ 
Ingredients % by Weight 
______________________________________ 
Meats Fibrous Muscle Meats 
27.3 
Offal Meats 16.2 
Ground Bone 6.5 
Gravy Amorphophallus sp. extract 
0.75 
kappa - carrageenan 
0.5 
Water 48.75 
100.0 
______________________________________ 
Using the above recipe the process of Example 1 was repeated up to and 
including the addition of the gums at 90.degree. to 95.degree. . When the 
gums were evenly dispersed, the mixture was split into two equal portions. 
Product A 
The hot mixture of one of the portions was poured into cans which were 
immediately sealed and transferred to a pre-heated autoclave. Without 
delay the cans and contents were heat sterilized at 130.degree. C. for 50 
minutes after which time they were cooled to room temperature by immersing 
in cold water. This product had had no ageing prior to the heat setting 
process. 
Product B 
The hot mixture of the second portion was poured into cans which were 
sealed and left to cool to room temperature overnight. After 12 hours at 
room temperature, the cans and contents were heat sterilized in a similar 
manner to Portion A. This product has been aged prior to the heat setting 
process. 
The meat analogues resulting from Portion A and Portion B were cut into 
chunks and subjected to the test for thermo-irreversibility and described 
in Example 1. 
Chunks from Product A were fused together to form a single lump. Some chunk 
definition was evident within the lump but the chunks were weak. 
Chunks from Product B were discrete, had clean surfaces and were tougher 
than the chunks from Product A. The pH of both products was 6.5. 
EXAMPLE 11 
This example illustrates the preparation of a thermally irreversible meat 
analogue product using raw meats. 
The product was prepared according to the following recipe: 
______________________________________ 
Ingredients % by Weight 
______________________________________ 
Fish 50 
Gravy Water 47.5 
kappa - carrageenan 
1.0 
Amorphophallus sp. extract 
1.5 
100.0 
______________________________________ 
The fish was chopped and then minced through a 5 mm screen. 
The gravy was prepared separately, by firstly heating the water to a 
temperature of 90.degree. C. The water was maintained at this temperature 
while the Amorphophallus sp. extract and the kappa carrageenan were added 
and dispersed using a high shear mixer. When the powders were fully 
dispersed, the gravy was added to the minced fish and the resultant 
mixture was homogenized using a high shear mixer. 
The product was then left to cool to room temperature before being 
processed in a pressure cooker at 110.degree. C. for one hour. The product 
was finally allowed to cool to room temperature before being assessed for 
appearance, pH, toughness and thermo-irreversibility. 
The thermally-irreversible product was tough with a texture similar to a 
meat loaf, the fish being evenly dispersed throughout the pack. The pH of 
the product was 7.1. 
EXAMPLE 12 
This example demonstrates the use of the glucomannan/carrageenan gel system 
to provide a meat analogue with high pet animal acceptance. 
1. Analogue Preparation. 
The following recipe was used: 
______________________________________ 
Ingredient % w/w 
______________________________________ 
Liver 12 
Offal Meats 28 
Fibrous Muscle Meat 
16 
Hydrated TVP 10 
Condensed Whey 3 
Carob gum 0.5 
Flavouring salts 0.2 
Dye Solution 0.7 
Water 26.5 
96.9 
______________________________________ 
The ingredients were mixed together and minced through a 4 mm plate. 
The minced product was stirred using a low shear mixer whilst adding 1.5% 
Amorphophallus extract and 1.6% commercial grade kappa carrageenan 
ensuring that the gums were well dispersed. The resulting mixture was 
heated in an autoclave for one hour at 130.degree. C. in a suitable 
container. 
After cooling, the solid pack was cut into chunks approximately 10 
mm.times.7 mm.times.7 mm in size to provide the meat analogue. 
2. Preparation of Pet Food. 
The following recipes were used: 
______________________________________ 
Product A Product B 
Ingredients % w/w % w/w 
______________________________________ 
Meat analogue (as above) 
70 -- 
Gravy A 30 -- 
Raw Meat Mix (as in 1 above) 
-- 97 
kappa Carrageenan -- 0.2 
(Commercial Grade) 
Water -- 2.8 
100.0 100.0 
______________________________________ 
Gravy A 
Ingredient % w/w 
______________________________________ 
Water 87.5 
Liver 12 
Dye Solution 0.3 
Flavour 0.2 
100.0 
______________________________________ 
The liver and flavour salts were added to the gravy to ensure that in 
Product A, the concentrations of these palatable ingredients were similar 
to those in Product B. 
Product A 
The appropriate weight of chunks analogue was added to the cans and the 
cans were filled with Gravy A to give the correct ratio of chunks to 
gravy. The can and contents were sealed. 
Product B 
All of the ingredients were mixed together and sealed in cans. 
Both products were heat sterilized @130.degree. C. for one hour. After 
cooling to room temperature the can were stored for one day at room 
temperature before opening to assess the contents. Samples of Product A 
and Product B were also fed to cats in a preference situation. 
Product A consisted of tough, integral, well defined, chunks of meat in a 
weakly gelled gravy. 
Product B consisted of a solid pack of minced meats embedded in a fairly 
tough clear thermo-reversible jelly. 
To a human panel the chunks from Product A tasted similar to the Product B. 
There was no detectable flavour difference resulting from the inclusion of 
Amorphophallus extract and carrageenan as the binder system in Product A. 
In Cat Preference trials, a panel of 40 felines ate both products with 
equal relish. 
EXAMPLE 13 
This example demonstrates the use of hot gum dispersion to aid the 
development of thermo-irreversible glucomannan/carrageenan gels. 
Two meat analogue materials were prepared: 
1. With gums mixed in the cold. 
2. With gums mixed at elevated temperature. 
Both had the following recipe: 
______________________________________ 
Ingredient % by Weight 
______________________________________ 
Offal Meats 12.8 
Fibrous Muscle Meats 
22.0 
Ground Bone 5.2 
Water 57.5 
kappa - carrageenan 
1.0 
Amorphophallus sp. extract 
1.0 
100.0 
______________________________________ 
For each meat analogue material, the meat constituents were roughly 
chopped, thoroughly mixed in their correct proportions and then minced 
employing the method illustrated in Example 1. The meat mix was then 
cooked by boiling in water for five minutes. The meats were strained, 
cooled to room temperature and employed in the following preparations: 
1. Cold Gum Dispersal. 
To 40 parts of the above meat mix 57.5 parts of water was added. The 
mixture was then thoroughly dispersed with a high sheer mixer. The 
required weights of gums were then dispersed into the mix whilst 
continually shearing for 1-2 minutes. The mixture was then poured into 
cans, sealed and sterilized at 130.degree. C. for one hour. 
2. Elevated Temperature Gum Dispersal. 
To 40 parts of meat mix 57.5 parts of water was added. 
The mixture was then heated to 90.degree. C. whilst continually stirring 
with a high shear mixer. The gums were then dispersed into the mix using a 
high shear mixer and maintaining the temperature at 90.degree. C. for 1-2 
minutes. The mixture was then poured into cans, sealed and cooled to room 
temperature prior to being sterilized at 130.degree. C. for one hour. 
Both samples 1 and 2 were allowed to cool to room temperature after 
sterilization, before being assessed for thermo-irreversibility employing 
the method illustrated in Example 1. 
Upon examination of the meat analogue chunks after the 
thermo-irreversibility test, obvious differences were apparent. 
1. Cold Gum Dispersal. 
The chunks had fixed together forming a continuous lump of meat and gel 
moulded to the shape of the can bottom. Gel had dissolved into the aqueous 
phase from the chunks producing a very viscous solution. The pH of the 
solid material was in the range of 6.30-6.38. 
2. Hot Gum Dispersal. 
The chunks were completely integral retaining their original shape before 
the test. They were glossy and juicy in appearance. The pH of the chunks 
was in the range 6.38-6.40. Some excess gel had diffused from the chunks 
to the aqueous phase to form a viscous solution. 
EXAMPLE 14 
This example illustrates the formation of thermo-irreversible gels 
employing a low temperature for a prolonged period of time. 
Two 1 liter portions of gel were prepared having the following recipe: 
______________________________________ 
Ingredient % w/w 
______________________________________ 
1. Amorphophallus sp. extract 
1.500 
2. kappa carrageenan 1.000 
3. NaH.sub.2 PO.sub.4 2H.sub.2 O 
0.382 
4. Na.sub.2 HPO4 0.618 
5. Water 96.500 
100.000 
______________________________________ 
The required quantity of water was taken for two liters of gel and heated 
to 90.degree. C. The water was then mixed using a high shear stirrer and 
ingredients 3 and 4 added. Ingredients 1 and 2 were then added and mixing 
continued whilst maintaining a temperature of 90.degree. C. for five 
minutes. The solution was divided into two equal parts, each being poured 
into an aluminium tray, covered and allowed to cool. 
One of the trays containing the gel was then heated to 76.5.degree. C. for 
a peiod of 16 hours, employing a constant temperature water bath and a 
thermocouple linked to a chart recorder to monitor the gel temperature. 
The gel was then allowed to cool to room temperature. 
Both the heat treated and non heat treated gels were then assessed for 
thermo-irreversibility employing the method illustrated in Example 1. 
Chunks from the non heat treated gel had completely fused together forming 
one continuous lump at the bottom of the can. The pH of the gel was 6.85. 
Chunks from the heat treated gel remained totally integral and retained 
their original shape. The chunks were tough and glossy in appearance. Some 
gum had diffused from the chunks into the aqueous phase but this was not 
excessive. 
EQU pH of chunks=7.01. 
EXAMPLE 15 
This example illustrates the effect of pH on the toughness of the 
thermally-irreversibility of the meat analogue product. 
Two products were prepared using samples of offal meat from the same 
source. The products were prepared to the same recipe as that given in 
Example 3, except that the fish was replaced by the same proportion of 
offal meat. 
The products were prepared in the same way as described in Example 3 except 
that prior to the addition of the gravy, the offal meat was treated with a 
suspension of calcium hydroxide in water to adjust the pH. 
When the preparaion of the products was complete, they were assessed for pH 
and toughness. Product (A) had a pH of 6.85 was thermo-irreversible and 
was markedly tougher than product (B) which had a pH of 5.65 and was 
thermo-reversible. 
EXAMPLE 16 
This Example illustrates the minimum heat input required to product a 
thermo-irreversible gel. 
A pH 7.1 buffer solution was prepared by dissolving the following salts in 
distilled water. 
______________________________________ 
Ingredient Wt/g % w/w 
______________________________________ 
Na.sub.2 HPO.sub.4 
49.44 0.618 
NaH.sub.2 PO.sub.4.2H.sub.2 O 
30.56 0.382 
Distilled Water 7920.00 99.000 
8000.00 100.000 
______________________________________ 
1 liter of pH 7.1 buffer solution was taken and heated to 90.degree. C. The 
solution was then stirred employing a Silverson high shear mixer whilst 
maintaining the temperature at 90.degree. C. 15 grams of knojac and 10 
grams of carrageenan were then dispersed into the buffer solution and 
mixed thoroughly with the Silverson high shear mixer for a period of five 
minutes. During this time the solution temperature was maintained between 
90.degree.-95.degree. C., after which the solution was poured into an 
aluminium tray, covered and allowed to cool to room temperature. A number 
of trays were made up in this manner and these were each heated for a 
period of 16 hours at a different temperature. 
Two methods of heating were employed: 
(i) 30.degree.-80.degree. C. using a constant temperaure water bath. The 
aluminium tray was submerged in the water to the upper level of gel. The 
gel temperature was then allowed to equilibrate with that of the water. 
(ii) 80.degree.-130.degree. C. using an Astell autoclave, vented to give 
temperatures up to 100.degree. C. maintaining atmospheric pressure and 
under elevated pressure to obtain temperatures up to 130.degree. C. 
The temperature of the gel was monitored in each case by means of a 
previously calibrated thermocouple linked to a twin channel chart 
recorder. A second thermocouple was also employed to monitor the 
temperature of the heating environment. Timing at any given temperature 
was started at the point where the gel temperature was in equilibrium with 
the heating environment. 
The following heating conditions were employed. 
______________________________________ 
Temperature .degree.C. 
Time/Hours 
______________________________________ 
100 16 
85 16 
76.5 16 
65 16 
61.5 16 
*50 16 
41 16 
______________________________________ 
The gels produced were assessed for thermo-irreversibility and toughness 
employing the following methods: 
Toughness 
The gels were measured for toughness employing an Instron food tester. 
The Instron food tester was set up as follows: 
______________________________________ 
Load cell = 50 Kg 
Crosshead speed 
= 500 mm/minute 
Chart speed = 1000 mm/minute 
______________________________________ 
The gel from each of the solutions prepared was emptied from its tray and 
the subjective textural characteristics of the gel were noted. 
Part of the gel was then cut into cubes having approximate side length of 
15 mm. 85-90 g of these cubes were transferred into a modified Minnesota 
cell which included a 10 mm screen. The chunks were then extruded through 
the screen by means of a plunger which was attached to the Instron load 
cell. The average toughness value was taken as the maximum load from the 
Instron recorder trace obtained. This procedure was repeated for four 
85-90 g. quantities of chunks and the average toughness value taken. 
Thermo-irreversibility 
The remaining part of the gel was taken and cut into chunks of 
approximately 1" side. 250 g. of these chunks were placed in a steel can 
and the remaining volume made up with water. The can was then sealed and 
processed at 129.degree. C. for 59 minutes in an Astell autoclave. It was 
then allowed to cool to room temperature prior to opening. 
A thermo-irreversible gel is confirmed if the gel chunks have retained 
their integral shapes and are not fused together. 
A thermo-reversible gel is identified if the gel chunks have melted and 
fused together in the bottom of the can. 
pH values of the gels were measured both before and after the test for 
themo-irreversibility. 
The results are illustrated in the following table: 
Results 
______________________________________ 
Temp. .degree.C. 
Thermo-irreversibility 
Colour Toughness 
pH 
______________________________________ 
100 Yes Opaque 2.8 6.9 
85 Yes Opaque 4.7 7.0 
76.5 Yes Opaque 6.0 7.0 
65 Yes Opaque 8.0 7.0 
61.5 Yes Opaque 10.0 7.0 
*50 Yes/No Opaque 9.0 7.0 
41 No Translucent 
6.6 7.1 
______________________________________ 
*Several experiments were carried out employing 50.degree. C./16 hours 
heating conditions which produced in some cases, gels which were 
borderline in terms of thermoirreversibility and in other cases gels whic 
were thermoreversible. It can be concluded that the minimum heat input fo 
thermoirreversibility lies at about 50.degree. C./16 hours. 
EXAMPLE 17 
In order to establish more clearly the effect of pH on the formation of 
thermo-irreversible gels in meat analogue materials a number of expeiments 
were carried out using meats at natural pH and at an artificially adjusted 
neutral pH. For the majority of the experiments the formulation used was 
as follows: 
______________________________________ 
Meat 50% by weight 
Konjac 1.5% by weight 
Carrageenan 1% by weight 
Water 47.5% by weight. 
______________________________________ 
For one experiment using lung the amount of meat was reduced to 40% by 
weight and the water content increased accordingly. 
The required amount of water for 1 Kg. of product was taken and heated to 
90.degree. C. This was then stirred with a Silverson high shear mixer 
during the addition of the required quantities of konjac and carrageenan. 
Stirring was continued until a homogeneous mix was obtained. 
The required weight of meat was taken and mixed thoroughly with the aqueous 
gel blend. The resulting mix was spread evenly into an aluminium tray and 
allowed to cool. 
The materials in the tray were heated to a temperature of 110.degree. C. 
for a period of 60 minutes in an Astell laboratory autoclave. The trays 
were then allowed to cool prior to being tested for toughness, pH and 
thermo-irreversibility using the methods described in Example 8. 
Results 
______________________________________ 
Meat Thermo-irreversibility 
pH Chunk toughness/Kg. 
______________________________________ 
Meat No 5.7 6.15 
trimmings 
Liver No 5.7 5.1 
trimmings 
Liver Yes 6.4 8.7 
trimmings 
Fish Yes 7.1 13.4 
Kidney Yes 7.3 7.3 
Lung Yes 7.2 11.7 
______________________________________ 
In those cases where the pH is below 6 and thermo-irreversibility is not 
acheived the meat is at its natural pH. In those cases where the pH is 
above 6.4 and thermo-irreversibility is achieved the pH was initially 
adjusted to 7-7.5 by the addition of calcium hydroxide. 
The results illustrate that when meat is present in the konjac-carrageenan 
gelling system pH is an important factor in determining whether the gel 
will be thermo-irreversible or not.