Note: Descriptions are shown in the official language in which they were submitted.
,~63~3G3
~ he prese~t invention relates to protein products
that are of value as food, more especiall~ for animals, but
also for human beings.
Whey protein (that is, the protein content recover-
able from wheys of milk origin) have been obtained having
- various functional properties by separation from acidic
cheese and casein wheys, followed by spray or other dryiug.
; Separation techniques which have been employed include direct
; acid precipitation of concentrated whey solutions at elevated
temperatures, precipitation of acid whey~ as metal-protein
, complexes, e.g. ferric whey precipitate a~ pH 2.5, and
;¦ precipitation of the protein by addition o~ salt, e.g.
ammonium sulphate, at pH 4Ø ~he reco~ery of whey proteins
by ultrafiltration of acidic wheys has also been described.
~he acidic whey protein obtained by these procedures
is ¢oagulable by heat but normally yields a hard, brittle ~ -
product of relatively low value as a binding agent. In the
recent past therefore, although tech~iques have been
established whereby functioni~l whey proteins can be obtained
from whey ~ge~erally regarded as a waste product), the whey
protein obtained has had limited applications ~nd valueO
We have now found that if the pH value of whey
protein is adjusted to within the range 6 to 9 at some stage
prior to heat coagulation i~nd îs coagulated at such a p~, -
then th~ coagulated product has a firm coherent texture well
uited to function as a protein matrix for food products
or as the basis for simulated animal products. It is also
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1~3863
very valuable as a binder in meat-containing products. The pH adjustment
- can be carried out by neutralising normal commercially available, dried~ -
acidic whey protein, for example at the time of formulation of the product,
but can instead be carried out on the freshly precipitated protein before
drying. In any case, a similar product is ultimately achieved after heat
coagulation.
Accordingly, one aspect of the present invention provides a method
of making a protein food product comprising the steps of: forming a mix com-
prising an aqueous solution or dispersion of acidic whey protein, said whey
protein having been separated from whey under acidic conditions; adjusting
the pH value of said whey protein or mix to within the range 6 to 9; and heat-
ing said mix at pH 6 to 9 to coagulate said protein.
Another aspect of the invention provides a protein food product
comprising a coherent matrix composed of heat-coagulated whey protein, said
whey protein having been separated from whey under acid conditions but having
at coagulation a pH of 6 to 9.
A variety of alkaline substances can be used for the neutralisation
~f acidic whey protein. Alkali metal hydroxides, such as sodium or potassium
hydroxide, are convenient but other hydroxides, such as calcium hydroxide, or
salts of alkaline reaction, such as sodium or potassium carbonates, sodium
tripolyphosphate or tripotassium orthophosphate can also be used. Where the
neutralisation is carried out at the stage of formulation of the product the
use of carbonates can give aeration of the product and result in a product
having a texture similar to that of a meat loaf.
~ In the simplest application of the invention, an aqueous solution
`~ or dispersion of whey protein is neutralised to within the stated pH range
and then heat coagulated to a firm, coherent mass, which can be used, with
flavouring,
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~063~63
as a foodstuf~, more especially for non-human use.
If the whey protein solution or dispersion is suffi-
ciently viscous, whether by ~irtue of a high concentration
of whey protein or by Pddition of thicke~ers, such as guar
gum, to ~he dispersion, to which may also be added fats,
colourin~ matter and other additives including nutritional ~ -
- suppleme~ts, the dispersion may readily be blanched in
boiling water (for example after extrusion) to form firm,
coherent pieces which simulate offal meats such as kidney,
and which may then be used in c~nned food products. ~he
~hey protein dispersion at pH 6 to 9 possesses good fat
emulsification properties, so that substantial proportions
of fat, which is nutritious but relatively cheap, can be
incorporated into the product without giving it an unaccept-
able, greasy feel.
~he neutralised whey protein can also be advantage-
ou~ly employed in admixture with vegetable proteins such as
wheat gluten, cotton seed protein and, more especially soya
protein flour~, concentrates or isolates. ~hese proteins
alone do not produce firm, coherent chunk~ on blanching in
~ater, but in a dispersion containing whey protei~ at pH 6
to ~ they modify the texture of the chunk, giving increased
elasticity and toughness.
j Preferred fo~mula~ions for coagulated, e.g. blanched~
1 25 chu~k products, for example simulating kidney9 based on whey
¦ protein contain 15-70% by weight whey protein, 30-85% water
1 a~d 0-45% other edible material. Where other substances
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having a thickening or binding property are present, the
proportion of whe~ protein can be less than 15%.
In another typ~ of product in accordance with this
invention, meat, meat by-products or other protein of animal
origin, e.g. sodium caseinate, is incorporated i~ the whe~ -
protein solution or dispersion or, conversely~ neutralised
whey protein may be incorporated as a birder in a meat-based
product to modify or improve the texture or flavour. Such
products can be used for human ~ood or for animal food.
When meat or meat by-proaucts are used in admixture with whey
protein it is preferred either to use denatured meats or
proteins or a meat of low iron content (e.g. chicken meat),
or to àdd a chelating agent for iron, such as trisodium
citrate or ~D~A, in proportion to the level of undenatured
animal protein. As an example of the use of neutralised whey
protein in a meat-based product may be mentioned sausage,
where the whey protein can be used to toughen the texture
and reduce the amount of binding meat required. The amount
of whey protein that can be incorp~rated is limited by the
necessity for a high level of chelating agent if much meat
is present.
In meat-containing products of this type, preferred
~ormulations contain 15-6~/o by weight whey protein, 40~ 8~/o
meat or meat b~-products, 0-45% added water, 0-20~/o other
edible materials and 0-7~% sequestrant. It will be appreci-
ated that by the term "meat" is meant not only the flesh of
mammals but also that of other animals, such as fish,
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~0638163
poul~ry or crustacea. Similarly, "meat by-products"
refers ~ot only to blood and offals o~ mammals but also to
the corresponding portions of other animals.
Iu yet another modification of the inve~tion, the
whey protein coagulated at pX 6 to 9 serves as a protein-
aceous matrix to bond other food materials in a composite
food. Such other foodstuffs ma~ include cereals, cereal
products such as rusk and biscuit, and nuts. ~he added solid
foodstuffs may be in the form of ground powder or meal or
; 10 granules or pieces. Fat, flavouring, colouring a~d other
` additives may be included, and the products may serve as
complete foods. They can, for example, be adapted for use
as complete dog foods, in place of conventional complete dry
i dog ~oods, but products of this type can also be suitable
- ' ' 15 for human food, depending on the nature of the solid food-
'~stu~fs incorporated.
I'Another variant of the inve~tion is to include i~
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''the whey protei~ product a proportion of one or more tha~
' one water-soluble humectant substance sufficient to maintai~
''' 20 a desired moisture content and reduced water activity (Aw)
'- in the product, for example in the dry or semi-dry range
from 5 to 20% moisture or in the semi-moist range from, say,
~ 20 to about 45%. In this way products can be obtained with
I a softer texture, and which may be stored without sophisti-
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:~ ~ 25 cated'packaging without hardeni~g or bacteriological deterior- '
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ation. Suitable humectants include polyh~dric alcohols, '
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~ugars, salts, other non-toxic low molecular weight water-
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~oluble compounds, low molecular weight polypeptides,
including fish solubles, or mixtures of these.
Particularly preferred products of this kind have a
moisture content in the range 5 to 20%~ and more especially
15 to 2C%~ and a water activity in the range 0.50 to 0~75,
- and msre especially about 0.65. This commonly requires a
level o~ humectant substances of 15 to 2~/o by weight of the
product. Preferred formulations for this semi-dry type of
product contain as essential ingredients 5-5~/o by weight whey
protein, 0-20% fat and 5-25% humectant, with a moisture
conten-t of 5-2~/o and a water activity of 0.60-0.75.
It is e~ually possible to utilize the invention in
the preparation of products of hi~her moisture co~tent, for
example with moisture contents in the range 20 to 45%, the
level of humectant being adjusted to produce a water activity
in the product which confers bacteriological stability,
notably in the range 0.75 to 0.85~ Preferred formulations
for such semi-moist products contain 10-40% by weight whey
protein, 10-4~/o humectant, and 0-2~/o other edible material,
with a moisture conte~t and water activity in the ranges
just mentioned.
Tha various modifications of the invention may be
combined. ~hus a whey protein matrix may incorporate a
number of particulate or granular ~ood~tuffs and may also
2~ contain a suitable amount of humectant to confer on the
product a softer texture which is maintained during storage
at ordinary temperatures and relative humidities. A parti-
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~63~363
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cularly preferred formulation for such a product contains
5-5~/o by weight whey protein, 0-2~o fat, 15-6~Jo solid food-
stuff or edible matter, 5-25% humectant and 5-20% water,
and the product has a water activity of 0.60-0.75.
~he ~ollowing are examples of the practice of the
inve~tion.
E3cample 1
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~ his example provides a simulated animal product
formed from a whey protein dispersion containing a thickener.
Whey protein (acidic) 30.~/o by weight
Water 5~-~/
t Dried blood ~.~/o " "
Dyestuff solution 2.4%
Beef dripping 10~/o
Guar gum 1.~/o
¦ Sodium hydroxide 1~/o ll ~l
~he i~gredients were mixed together in a high speed
homogeniser, the sodium hydro~ide being first dissolved in
the water. ~he mix, which had a pH of 7.5, was then ex-
truded through a mincer into a hot water bath at 95 to 100C. -
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~he extruded cylinders were cut off into ~-inch pieces at
the mincer plate, blanched in the hot water for 3 minutes
and cooled.
The product was fi~m and coherent and had a smooth
internal texture closely similar to that o~ organ meats such
as kidne~ It may if desired be passed throug~ a cutting
machine to simulate the sharp edge appearance of cut kidneys.
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~ he product was sufficiently tough to withstand
mechanical handling. A~ter sterilisation in cans in a meat
miX, the product surface readily shed the gra~y and meat
mousse background in a similar manner to the surface of
real kidney.
~xample 2
Example 1 was repeated but with the substitution of
` 8.3% fresh blood and 1~G% trisodium citrate for the dried
;~ blood. The amount o~ water was adausted accordingly to
46.1%.
- ~he product obtained was similar to that of Example
.
Example ~
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Example 1 was repeated with the exception that instead
of sodium hydroxide, potassium carbonate was added until a
pH of 8.0 was achieved~
~ he resulting product had an aerated texture similar
to that of meat loafO
~ le 4
~h; S example demonstrates the use of vegetable
protein in conJunction with the whe~ protein~
Example 1 was repeated but with the substitution of
, - 2~h whey protein and 1~/o soya protein concentrate for the
~/o whey pxotein of the original example.
The product obtained was in the form of a very
tough chunk with a dense lung-like texture.
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1~63863
~ his example demonstrates the use of whe~ proteis
to bind meats in a sausage type product.
Whey protein (acidic) 25~3% by weight
Meat off-cuts 23.~/o
~ripe 11.~/o ll ll
~rotters 15.4% " "
Blood 15.~/o
Salt 2.~% " "
Trisodium citrate 5.~/o
Sodium hydroxide 1.2% ll 1'
~he sodium h~droxide and trisodium citrate were
dissolved i~ the blood and immediately mixed with the meats
which had pl~eviously been finely macerated. ~he mix, which
had a pH of 7.5, was extruded through a mincer plate and
blanched as in Example 1. ~he product was a firm discrete
I chunk similar to meat balls prepared in a ~imilar way but
; having the whey protein replaced with expensi~e binding meat.
~he final pH of the product was about 6.60
Example 6
` ~his example demonstrates the use o~ whey protein
~eutralised prior tv drying.
~o 3 litres of cheese whey was added sufficient
hydrochloric acid to reduce the pH of the salution to 4Ø
~he solution was heated to the boil and 5 ml of 30% calcium
chloride was added dropwise with stirring. After 15 minutes
the mixture was cooled to room temperature and oentrifuged
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363
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~ at 5000 rpm for 10 minutes to collect the p~ecipitate.
; After being washed twice with dilute hydrochloric acid
solution the sediment3 comprising the whey protein, was
neutralised to p~ 700 with sodium hydroxide solution and
dried at 60C in an oven~
The following formulation was made up
Neutralised whey protein 3~/o by weight
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: Water 6~.~%
Dried blood ` 1.~/o 1~ It
Dyestuff solution 2~4% " "
Guax gum 1.~/o 't ~l
¦ ~he mixture was heat coagulated as described in
Example 1 and produced coherent firm chunks. In contrast,
whey protein separated and dried without ~eutralisation9 did
not produce chunkæ when used in the same fo~mulation by the
I same process, but merely separates as a scum.
¦ ~he two following examples describe the production
of complete food products co~taining humectants and anti-
mycotics a~d are suitable for storage under ambient
oonditions withouO loss o~ textu~e.
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~(~6,31563
~Z
.- Whey protein 12.6% by weight
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Sodium caseinate 12.6% " "
Rusk 44.1%
Beef dripping 5.~/o
Vitamin mix 4.6%
Choline chloride solution O.ZYo
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.. Glycerol 5.~/o " "
: 10 Sucrose 1305% " "
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:~ Salt 1.5% " " :-
.~t Potassium sorbate 0.~/oI Dyestuff solution 0.6% " "
;s` Wet mix:
. 15 Dry mix 78.03% by weight
I Water - 21.14% " "
I Sodium hydroxide solution 0.83%
(25% W/w)
~he dry ingredients were weighed into a bowl mixer
: fitted with a spade attachment and the beef drippi~g
.~ (at 60a), dye solution and glycerol, water i~nd sodium
hydroxide solution were added during mixing.
The wet mix, which had a pH of 6.5, was spread in a
~-i~ch layer on greased trays9 the sur~ace brushed with fat
and the mix baked at 375F for 21 minutes in an air-
circulating ovenO
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~0638G3
~ he final product was cut into ~-inch sized pieces
and pac~ed. The product had a moisture content of 15.~/o and
a water activity (Aw) of 0.70.
In a dog feeding trial the product was found to have
a much higher acceptance than a traditional dry complete dog
food, which had a cereal-based structure.
~ he product had a sweet, nutty taste to the human
palate and a firm, coherent texture, whereas a similar
product prepared without neutralising the whey protei~ had
not only a hard, brittle texture but a sour, u~pleasant
taste.
After storage for one month at ambient temperature
in the relative humidity range of 55 - 8~o the product was
found to be bacteriologically stable and had retained its
firm, coherent texture.
Ex~mple 8
Dry mix:
Whey protein 130~o by weight
Sodium caseinate 13.~/o ~l
... .
Arachis oil 5.0% "
Roasted peanuts 45.~/o ~
Vitamin mix 4.6% " "
Choline chloride solutio~ 0.~/o "
Glycerol 5.oo/o ~
Sucrose 13.5% " "
` Potassium sorbate 0.1% " "
Dyestuf~ solution 0~6% " "
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1063863
Wet mix
:. Dr~ mix 78.0~% by weight
Water 21.14% " 1l
Sodium hydroxide solution 0.83% " "
(25% W/W)
:~ ~he product was prepared as described i~ Example 7 :
(the mix having a pH of 6.8) and had a firm, coherent
texture, and could readily be cut into suitably sized
pieces. The final pH of the product was 6Ø
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