Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
346fo9
~ .1009
_ H~DR~TED EDIBLE PRODUCTS
The present invention relates to dehydrated edible
products, and in particular to products including pieces
or particles o~ comminuted food, ior example derived irom
pureed meat and vegetables.
Dried ~oods capable o~ reconstitution on the addition
o~ water are well known. Examples include soups, desserts
and snack products. Some of these products, o~ten referred
to as iinstant', are suitable ~or consumption within a ~
short time a~ter reconstitution, e.g. 1-2 minutes, while
others require a longer period of soaking to allow the
constituents o~ the food to rehydrate. Clearly,
specification of the rehydration conditions depends on the
nature of the ingredients comprising the iood. When the
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~ood contains pieces o-f dried vegetables or meats,
simmering in boi]ing water -for up to 20 minutes may be
required and con~equently such foods are not acceptable as
instant products.
Instant products comprising dried food pieces such as
dried vegetables and dried meats are commercially available.
These may be obtained by freeze-drying pieces of the
appropriate food. However, pieces obtained by such a
process do not al~iays possess all of the desired
characteristics: e.g. the rehydra-ted product may be
spongy and may be deficient in flavour, colour or texture,
so that it may entirely fail to resemble the original
foodstuff. ~s an example, it has been found that rehydrated
free~e-dried tomato pieces can be undesirably light and
spongy and lac~ing in flavour. In addition, such pieces
are also expensive.
An alternative source of dried edible products is
described in the prior art (Belgian Specification No 836 19~).
These are made by preparing a dispersion of comminuted
foodstuff in an aerated calcium alginate or calciu~ pectate
gel, cutting the gel into pieces and drying the said
pieces. Use of an aerating agent is expensive and may also
in some cases result in an undesirable spongy te~ture in
the rehydrated pieces. ~his approach, therefore, a]so has
disadvantages.
We have surprisingly discovered that unaerated alginate
gels containing comminuted foodstuffs, e.g. purees, after
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cut-ting and air dry:ing, c~n be so made as to provide dried
foodstuff pieces which are acceptable for use in instant
produc-ts~
The abili-ty of alginate solutions to form films on
drying is well known. Consequently, it would not be
entirely surprising, and in fact we find, that pieces o~
alginate gel also tend to form films after air drying. In
some cases, depending on the geometry of the gel piece~
prior to drying, a dried ou-ter skin with a hollow interior
is obtained. Such an effec-t can be ob-tained when drying
gelled dice. It has to be noted, moreover, that the dried
materials so obtained have very poor rehydration
characteristics.
In contrast, by including a comminuted foodstu~ in
the gel matrix in accordance with the present invention as
described below, an excellent texture simulating vegetable
or meat pieces can be obtained after rehydration o~ the
air-dried gel piece~. Without being bound by theory, the
presence o~ the comminuted food particles appears to hinder
collapse of the alginate network with the accompanying iilm
formation and provides in the dried products particles of -
.
comminuted food dispersed throughout a dried al~inate matrix.The food particles are thus free to hydrate on the addition
of water but in so doing, are prevented from ~eparating by
the alginate matrix. Discrete rehydrated particulates
result.
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According to the invention there is provided a dehydrated
edible product obtained by drying a co~position comprising a finely
divided, e g comminu-ted or pureecl, foodstufP dispersed in an
edible (and preîerably thermostable) gel which has not been subjected
5 to aeration and which has a gel strength corresponding to a value
of at least 200 grams when determined by the method defined below
Since the gel has not been subjected to aeration, it has beIore
drying either no overrun or else a minor amount due to unintentional
incorporation of bubbles not sufIicien-t to render the material a
lO foam, e.g. notmore thanlO/O, preferably5/Oorless, e.g. less than-
1%, for example 0.5%,
Desirablythe product is capable of satisfac-toryrehydration
in 60-120 seconds of immersion in ~ater, e.g. hot water. Of course,
the gels are prepared without addlng aerating or foaming agents as
15 such: any constituents which are added for other reasons and are
capable of promoting aeration are preferably restricted to levels
at which any foam_promoting effects are negligible.
In order to produce a dried product capable of satisfactory
rehydration, the drying is preferably carried out by air-dryin~ or
20 oven-drying~
The gel strength can be measured with a commercial Instron (Trade
Mark) test machinewhich compresses a gel of defined size betweentHo
plates at a defined speed: the stress increases to a peak at the yield
point and the yield stress measures the gel strength. The gels used
25 in this invention have at least 200 grams gel strength for a cylind-
rical gel sample 12mm diameter and 12mm high, compressed at 5cm/minute
Desirably the strengths are even higher, corresponding to 350 or more
and can conveniently reach 600 or 700 or more.
One highly desirable ~ethod of producing gels~hich give
30 satisfactory dehydrated products according to this invention
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-- 5
is a fast-setting method (e.g. with gelling time below 30 min-
utes, e.g. 6 minutes), e.g. as described in our co-pending
Canadian Patent Application 335,287: the method disclosed com-
prises mixing solid calcium sulphate particles, for example as
an aqueous slurry with a comminuted foodstuff, rapidly through-
out a gellable aqueous alginate or low-methoxy pectate sol, and
then under shear-free conditions allowing solid calcium sul-
phate to dissolve and the mixture to gel.
However, other methods of producing the gels to be dehy-
drated are also usable in the performance of this invention,e.g. that described in our UK Patent Specifications Nos 1 369
198-9. It relates to rapidly making a mixture comprising an
alginate or a low-methoxy pectate sol, a source of calcium ions
(e.g. dicalcium phosphate) that in the absence of an agent cap-
able of releasing calcium ions (e.g. acid) provides insuffi-
cient calcium ions to gel the sol, fruit pulp or puree and an
agent capable of releasing calcium ions, and allowing the mix-
ture so made to gel under substantially shear-free conditions.
Using this invention, dried pieces of vegetables and meats
which possess excellent colour, flavour and texture after re-
constitution for 1-2 minutes in water have been produced.
After formation, the gel may be cut to the desired shape,
e.g. dice, strips, and dried on commercial air-drying .....
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- 6 - Q.100
equipment, e.g. an oven or through draugh-t drier. The
preferred temperature range for drying is 60-80C. Use
of lo~er drying tempera-tures result~ in extended drying
times while use of higher temperatures can result in -
unacceptable flavour lo~s and charring. ~lternatively,
drying may be carried out or facilitated with the aid o*
a vacuum and/or a desiccan-t such as P205 or calcium
chloride. For most applica-tions it is desirable to dry the
particulates to a ~inal mois-ture content of ~-12~/,
preferably ~-9~, e.g. 7~0. , Choice of the appropriate drying
condi-tions depends on the -type of gelled comminuted food
to be dried and its intended usage. Such condition~ are
,." . .i
readily determined by simple experiment. It may be desirable
to carry out two-stage drying with intermediate storage for
a period to allow equilibration of the water content of
the partially-dried material.
When the products are used as ingredients in instant
foods, best results are obtained by rehydration for 1-2
minutes in boiling water.
When necessary, rehydra-tion may be improved and the-
texture of the rehydrated particulates suitably modified
by the addition of a texture modifying agent during the
gel preparation step. Such texture modifying agents are
normally pro-teinaceous or carbohydrate in nature, for
example, caseinates, albumen, gelatin, starch derivatives,
cellulose derivatives, carrageenans, xanthan gum etc.
For economic reasons, an inexpensive texture modifying
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agent is pre-~erred. Pre-cool;ed or modified starches at a
level of around 0. 5-3% by weight o~ the gelled comminuted
food have been found -to give acceptable results.
The dehydrated products o~ -the invention can be in `-
the form of particles, slices or small blocks or otherconveniently-shaped regular or irregular pieces.
Although the products of the present invention can be
used acceptably in instant products, they maintain their
~tructural integrity and organoleptic quality under more
prolonged and extreme conditions of rehydration, e.g.
boiling in water for 20 minutes, and can, therefore, be
used generally as ingredients in dry food products, e.g.
dry soup mlxes.`
The invention i~ illnstrated by the following
examples, the table given below showing the composition of
the mixtures used therein.
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Example l
~ gel containing ~0% by weigh-t of comminuted tomato
(28-30% solids) was pr~pared by mixing together an
alginate phase and a comminuted food phase, formulated as
shown in the accompanying table, and allowing -the mix to
set under shear free conditions. q'he gel was cut in-to
parallelepipeds with edges varying between 0.~-2.0 cm
which were dried on a commercial through draught drier at
75C for ~ hours. The dried product had an average
mois-ture content of 8.7% and rehydrated.in boiling water
after ca one minute to provide tomato slivers of excellent
taste and pleasant texture.
Example 2
A gel containing ~0/0 by weight of comminuted c~oked
. 15 chicken was prepared as in Example 1 using the formulations
for the alginate phase and the comminuted food phase shown
in the accompanying table The gel was cut into cubes o~
0.8 cm edge which were dried on a through draught drier at
70C for three hours. The dried product had an average
moisture content of 8.1% and on rehydration in boiling
water attained a fibrous texture somewhat akin to cooked
chicken after two minutes.
Example 3
A gel containing 30% by weight of comminuted red
pepper was prepared as in Example 1, u~.ing the formulation
show.n in the accompanying table. The gel was cut into
parallelepipeds (1.5 cm x 0.6 cm x 0 ~ cm) which were
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dried on a bcnch--scate ilu;dised bcd drier (~'odel FBD/L72*
ex P~L Eng-ineer~ng Ltd) at 70C for 2.5 hours. The result;ng
dried -product of average moistllle content 6.1~o still
retained its strong red colour after nine montll~ storage
and rehydrated in boiling ~ater aftcr ca. one n]inute to
provide ~imulatcd pepper picces with excellent colour,
flavour and texture.
. * Trade Mark
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