Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The invention relates to a process in which an
object having at least a coating of an alginate or
low-methoxy pecta-te sol is dropped or thrown into an
aqueous se-tting or hardenin~ solution.
Such processes have been propossd in particular for
encapsulation of liquids and o-f solids, In encapsulation
processes the object has only an outer coating of the sol.
As far as the present in~ention is concerned it is preferably
applicable to such processes but is also applicable to the
situation where homogeneous drops of the sol are dropped
or thrown into an aqueous setting or hardenin_ agent,
A particular example of such a process is described
in thespecification of Netherlands patent applica-tion
7400889 and the specification of its corresponding Canadian
patent 1,008,29~,
A problem is that the impact of the object on enterin~
the setting or hardening solution affects the quality and
possible throughput of the product, The impact can distort
the shape of the object, if it is liquid, and also distort
or displace the coating, A further problem is that splashing
disrupts objects entering the setting or hardening solution
later,
It has now been found that these effects can be
overcome or at least mitigated by foaming the surface of
the setting or hardening solution,
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The in~ention therefore provides a process in which an
object with at least a coatin~ of an alginate or low-metho~-
pectate sol is dripped or thrown into an aqueous setting
or hardening solution in which foaming ta~es place where
a the objects enters.
The -foaming should preferably be such that the surfac~
of the aqueous setting or hardening solution is raised be-t~een
2 mms and 25 mms. Foaming is to be taken to cover the
situation lihen there is constant breaking of the surface
1t~ of the aqueous setting or hardening solution as well as
the situation where there are bubbles of gas with an
appreciable life-time. Indeed, it has further been found
that a preferred method of foamin of the aqueous settin~
or hardening solution is by blowing air into the aqueous
1-~ setting or hardening solution so that bubbles of air are
constantly breaking at the surface. Any gas can be used that
is non-reactive in the process used. Air will often ~e
most convenient.
Particularly preferably the foaming raises the surface
Or the aqueous setting or hardening solution between 2mms and
10 mms.
The invention is particularly applicable to processes
in ~hich a liquid is encapsulated by co-extruding the liquid
and the alginate or low-methoxy pectate sol to give a coating
to the sphere of the first liquid formed on extrusion and
dropping the coated sphere into the aqueous setting or harde~lin~
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solution. Examples of~ such processes ha~e been mentioned
above, in particular reference should be made to the
specification Or or its corresponding Canadian patent
lOOS294 and Netherlands patent application 7400~89. In
such a process the co-extrusion nozzle is preferably 2-~0 cms
above the surface of the aqueous setting or hardening
solution and, as stated in the Netherlands specification,
it is particularly preferably 5-20 cms above, especiall~-
about ~0 cms above the aqueous setting or hardening solution
(i.e. from the top of the foamed surface).
It has now been realised that in co-extrusion impact
of the coated object on the liquid setting or hardeninF agent
causes special problems : there is a surprising likelihood
that splashes of the aqueous setting or hardening solution
1~ will hit the co-extrusion nozzle and, by causin_ at least
incipient setting or hardening of the sol, interfere ~ith
proper formation of the coated drops. The present invention
is particularly successful at alleviating this problem.
Particularly when a number of co-extrusion nozzles are used,
for example, in a head containing a number of nozzles,
methods described in the prior art are less successful.
In one such prior art method the drops fall into a slopinF,
flowing setting bath. The present process has the
advantage of simplicity but with a number of nozzles also
_~ elim nates the problem reliably. The prior art method
does not eliminate the problem so reliably.
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As the aqueous setting or hardening solution aqueous
solutions of a calciul~ or other alkaline earth sal-t are
preferred. An aqueous solution of an edible calcium salt
is particularly convenient as the aqeuous set-ting or hardening
solution. Preferred calcium salts are calcium lactate,
citrate, gluconate and acetate. Preferably the concentration
of calcium ions provided by the water-soluble calcium salt
in the setting or hardening solution is equivalent to that
provided by 1-10%~ by weigh-t, particularly 4-7,~, of calcium
lactate.
In a preferred form of -the invention i-t is applied to
the preparation of simulated fruits : for instance a
fruit-flavoured aqueous solution or suspension preferably
based on fruit pulp or puree is co-extruded ~iith an alcinate
1, or low methoxy pectate sol to give fruit-fla~oured drops coated
with the sol. These drops are then dropped into an aqueous
setting or hardening solution containing an edible, water-
soluble salt The fruit-flavoured aqueous solution can,
but need not necessarily, contain such a water-soluble,
edible salt. For details of a preferred such process reference
should be made to Netherlands patent specification 74008~9 or
its corresponding Canadian patent 1,008,294.
T The accompanying drawing is a diagram of a preferred
form of an apparatus suitable for preparin_ products b~- a
process according to the invention (A) is a sche~atic
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sideview an~ (B) is a schematic plan of the apparatus.
detailed process usin~ the apparatus is described below
and is illustrated by an example. Fur-ther details can be
found from Netherlands patent specifica-tion 7400889 or
a the specification if its corresponding Canadian patent
1,008,294. The following also indicates further preferred
aspects of the invention.
Objects 1 (coated or homogeneous) are dispensed from
a forming nozzle 2 and fall to an aqueous settin_ or hardening
solution 3. ~he nozzle 2 is placed preferably 20-300 mm abo~-e
the foamed surface of -the solution 3. A supply of compressed
non-reactive gas is delivered to the tube 4 and released throu~h
a series of fine holes 5 preferably 0,01 - 2.0 mm in diameter.
The gas is released beneath the surface of the solution 3.
1.5 ~h~-g-as-is released beneath the surface--~f the--solution 3-,
The distance to the foamed surface of the solution 3 is
preferably from 20 mm to 150 mm. Bubbles of gas rise to the
surface forming a foam 6 raising the effective surface of the
solution 3 by 2 mm to 25 mm. The objects 1 fall into the
foam 6 and preferably are light enough to float in the solution
3. The solution 3 is circulated through an inlet pipe 7
moving the floating objects away from the foaming area. A
wire mesh 8 separates the objects from the foam-forming
tubes.
2~ EXAMPLE I
Homogeneous drops of a solution containing,by wei~ht, : _
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Sodium aleinate 1.0
Su~ar ~
Colouring + Flavouring 0.5
Water 94~5
- 100.0
fall 10 cm into anaqueous setting or a hardening solution
eontaining by weight :- ;
Caleium lactate 6.0
Sugar 22.0
~alic acid 0,5
Water 71.5
100.O
The settina or hardening solution is -foamed by eompressed
air pumped beneath its surface. The foam raises the
surface of the solution by 10 mms. The apparatus is
1.~ as described above in relation to the Figure. Flavoured
drops are obtained in high and eonsistent yield.
EXAl~PLE II
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A blaekcurrant pulp mix eontaining caleium ions was
prepared by mixing together the -following ineredients:
/0 by weight
Blaekeurrant pulp41.1
Water 42.~
Caleium laetate 1.0
Citrie aeid 0.2
~-5 Sugar 12.7
Cross linked farina1.7
Carboxymethyl eellulose O.a
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:- . ~ . :
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An alginate sol containing 2% by weight of sodium alginate
was separately prepared.
The above ingredients were fed to the apparatus illustrated
in Canadian patent 1,008,294. The blackcurrant pulp mix was
pumped along a supply line of the apparatus at a rate of 3 kg per
hour and the alginate sol was pumped along another supply line at
1 kg per hour. The pneumatic pulsator attached to the air line
was set to operate at 160 pulses per minute. The apparatus used
had a tube with an extension outlet of 5 mm diameter and a jacket
with an inner diameter of 9 mm (corresponding to an annular width
for the chamber in the apparatus of 2 mm). The bath in the
apparatus contained a 3% by weight aqueous solution of calcium
lactate.
Drops of blackcurrant pulp coated with alginate sol were
extruded from the outlet at a rate of 160 per minute. The bath was
foamed by compressed air pumped beneath the surface of the bath as
described above in relation to the Figure of the present application.
The surface of the bath was raised by 10 mms. The drops, obtained -
in high and consistent yield, were left immersed in the bath for
5 minutes after which time the exterior was firm and had lost the
stickiness characteristic of an alginate sol. The products could
be easily handled without breaking. When canned in an aqueous
syrup and sterilised at 100C for 30 minutes the simulated black-
currants formed had a texture remarkably similar to that of real
cooked blackcurrants.
