Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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._ This invention concerns improvements in additives
for food products. More particularly, it con_erns such
addLtives whicll are manufactured from animal connective
tissue, particularly from beeE. Such tissue inc~ucles
material known as "paddiwak" which is a neck connective
tissue, but also includes all connective tissue e.g.
gristle and ligaments whicb connect meat with bone, bone
with bone or meat with meat.
Connective tissue in comminuted form is used in the
meat industry in some rneat products, for example
hamburgers. It provides~an economical source of protein,
and may be employed in varying proportions depending on
the legally permitted amount for that product. However,
15 because of its nature the material is extremely difficult
to use successfully. It can only be used if it has been
extènsively processed e.g. by boiling or emulsification
; ~ or by a combination of both. As a result~, it has only
been used in small proportions to the total product to
supplement~meat protein in products at the lower quality
end of the market. Much more often than no~t thè material
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has simply been discarded and has in many cases not even
found application in animal Eoods. Thîs has resulted in
the discarding of large quantities of protein at a time
when the neecl to utilise all possible sources of protein
is increasing.
Any processing of the connective tissue that occurs
is a time-consuming and labour-intensive operation.
The manufacturer must accurately predict his require~
ments for the tissue in order to avoid the loss of
inexpensive protein derived from the tissue which
would either have to be replaced by other sou~ces of
protein, normally more expensive, or not be replaced at all.
It has now been found that it is possible to
process connective tissue into a dehydrated powder form
in which it ls micro-biologically stable for extended
periods and can readily and rapidly be rehydrated
into a usable high-protein fGrm. In powder form, the
product i5 highly suitable as a protein su?plement for
inclusion in, for example, com~inuted meat products that
are suitable for human consumption.
According to one aspect of the present invention there
is provided a dehydrated, bacterlologically stable,
connective tissue product having a water content of less
th~n '0% by weight, a fat content of less than 10% by
~5 weight, and a particle size of less than 5mm, the dehydrated
product being capable of inclusion in a meat product.
Water content may be assayed by placing a weighed
sample of the material in a constant temperature oven
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at 105 C for four hours, allowing the sample to cool in
a desiccator, re~eighing and then calculatlng the percentage
loss of moisture.
Fat content may be assayed by solvent extractionJ
e.g. with petroleum spirit.
The water content is preferably in the range
4 to 9~/O by weight, typically from 4 to 6% by weight.
The fat content is generally in the range 2 to 5 %.
It is preferred that the water and fat contents be
as low as possible~ consistent with the production
of a substantially stable product.
The dehydrated product is mainly protein, this
typically constituting between 80 and 96% by weight
as calculated from the nitrogen content (protein
content = nitrogen content x 6.25). The nitrogen
content may be assayed in conventional manner e.g.
after digesting a sample with sulphuric ac~.d using
a catalytic mixture of copper sulphate and sodium
sulphate.
The particle size is of great importance to the
properties of the product when included in a comminuted
meat product. Rehydration speed decreases as particle
size increases. For most purposes~ in order to
ombine rehydratability with ease of handling, a
particle size in the range from 0.005 to 2 mm is
preferable, a range of ~rom 0.005 to 0.~ mm being
even more preferable.
The dehydrated product has an appearance like that
of talcg but is pale to dark -rown.
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The dehydrated product can be stored for several
months without refrigeration in ambient temperatures
of 13-19C.
The dehydrated product may be manufactured~
according to another aspect of the invention, by
drying ~resh connective tissue to a water content of
less than 10% with simultaneous removal of fat to a fat
content of less than 10%, rapidly cooling the product
and comminuting the product to a particle size of less
lO than 5 mm.
The product may be dehydrated in a variety of ways
employing heat or cold. Air, oil, or a combination of
both air and oil methods may be used at elevated temperature
prior to cooling, or the product may be freeze dried.
15 Dehydration is preferably carried out at from 80 to 150 C.-
~ he dehydration may be effected at reduced pressure,in which case lower temperatures may be employed. If
desired part of the dehydration may be effected at
reduced pressure and part at atmospheric pressure.
The temperature must be care-fully controlled at
- all stages of production to prevent degradation.
In order to ensure reasonably rapid dehydration, an air
temperature in the upper limits of the range previously
indicated is preferred for the initial stage of the
25 dehydration. High temperature has been found to be
disadvantageous as it tends to prevent rehydration of
the product. At the same time, a proportion of ~he
fat originally present in the product is rendered off,
and removed.
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As the water content of the product falls, the
temperature oE dehydration may be reduced and should
be carefully controlled in order to prevent
degradation of the product.
It is possible to reduce the moisture content
down to the final value (typically 4-6%) by careful
drying. It may be preferable to control the final dry-
ing stage, particularly if this is carried out in heated
oil, for example in a steam-heated rendering vessel.
When the required moisture content has been reached,
the excess oil is drained away.
The product may, if so desired, be centrifuged
or treated with a food grade oil solvent or both in
order to reduce further the fat and oil content.
~fter dehydration~ the product should be cooled
as rapidly as possible in minimum contact with
the atmosphereO In batch processes it may be
convenient to cool first to ambient temperature before
effecting further processing.
The adjustment of particle size will generally
take place after dehydration has been completed, though
it may be convenient to effect at least some adjustment
in particle size before dehydration in order to facilitate
the carrying out of the dehydration process. Where the
final adjustmen~ in particle size is effected after
completion of the dehydration, the dehydrated product
may be comminuted at ambient temperature (13-19C) or,
alternatively it may be frozen prior to comminution.
Although freezing may be-effected in a refrigerator
or freezer, it has been found to be preferable to effect
this by treatment with a cryogenic medium e.g. a solid
or liquid gas, particularly solid carbon dioxide or liquid
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nitrogen.
Freezing with the cryogenic medium appears to result
:in a microcrystalline-like structure of the dehydrated
product as a result oE the rapid fa]l in temperature.
Such a structure is readily broken down on comminution
andlubrication effects, due to the ~at, do not occur
in the comminutor while the product is in,a frozen state.
The resulting commlnuted product may then be stored at
ambient temperature.
The dehydrated product may be added to fresh
meat products, for example hamburgers and sausages.
It may be added to baked meat products such as pies,
cooked meats, canned meat products (e~g. canned
hamburgers) pastes and soups. The product will absorb
at least its own weight in moisture in such products and
will retain it during subsequent heat processing. At the
small particle sizes employed, it has the advantage
of being practically indis'cërnible in the comminuted
meat product though the protein content of the meat
product will be greatly increased,
It may also be incorporated into products
' containing meat but which are not in themselves meat
products, e.g. dried products such as dried soups.
The dehydrated product ma~ be added, without previous
rehydration, to such'products providing that during
a processing cycle rehydration occurs before
consumption.
The quantity of the product which is added to
food stuffs containing meat will depend on the permitted
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requirements being met in the finished product.
Generally speaking,in the U.K. for e~ample not more than
5% by weight, calculated on the meat, will suffice3
though in other countries larger quantities e.g. up to
20% may be perrnitted.
It will be understood that the dehydrated product
may be blended7 if desired7 with other materialst
additives; stabilisers and emulsifiers employed in
the food processing art, e.g. vegetable proteins,
animal proteins 9 or products normally associated
with or added to meat products and products containing
meat.
It is a particular advantage of the dehydrated
product according to the invention that is has a
lS long storage life at ambient temperàtures. The
presence of antioxidants and preservatives is not
generally necessary, although these may be added in
the concentrations customarily employed iE the
storage conditions are particularly severe.
In order that the invention may be better
understood, the following example is g;ven by way of
illustration.
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Example
A. ManuEacture of dehydrated connective tissue
2~ 1000 kg beef neck connective tissue is comminuted
into pieces of approximately 1 square inch in surface
area, though this measurement is not critical.
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The tissue is then transferred to oil (or fat)
contained in a heated vessel. The tissue and oil
(or fat) are constantly stir-~ed at a temperature of
about 125C until the moisture content is reduced to
the desired final value of about 4-6~/o~
The now dehydrated tissue-is removed from the oil
(or fat), is drained and is then spun to remove still
further oil (or fat). The tissue is then transferred
to a closed vessel and liquid nitrogen is blown into
it in order to reduce the temperature rapidly.
The resulting product is immersed in liquid
nitrogen at about -75C for 3-6 minutes and is then
ground to produce a final product having a particle
si2e of about 0.1 mm.
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