NO132943B - - Google Patents

Description

The invention relates to a method for producing fruit products in encapsulated form. More particularly, the invention relates to a method for producing a fruit product comprising fruit puree or fruit puree encapsulated in a skin or film of calcium or aluminum alginate or pectate gel.

The method according to the invention can

e.g. used for the formation of products with a non-uniform texture that imitates the texture of soft fruit, e.g. blackcurrant and

currants; where a relatively thin shell surrounds an interior which, because it is fluid or plastic (ie flows easily under light pressure), is soft_

It is known e.g. from Swedish patent no. 139,501

that when an alginate sol is brought into contact with a calcium salt solution, an alginate gel forms at the interface.

According to the patent, artificial fruits are produced for decoration purposes, containing flavoring and coloring substances, but no fruit material. Drops of an.alginate sol which. contains. syrup, flavorings and colorings are dripped into a calcium-salt solution. A gel skin forms around the drops, and the calcium ions from the salt solution gradually diffuse into the sun and thereby cause progressive gelatinization. The products produced by this method are not used in fruit pulp. or -pure are poor imitations of natural fruit,... especially from a textural point of view. " They are stretcher "decorative fruits"

and lacks the texture provided by real fruit material

as fruit pulp. Furthermore, if it is desired to imitate soft fruits, e.g. blackcurrant, then the method according to Swedish patent no. 139,501 cannot prevent the calcium ions from diffusing to the center of the alginate sol so that it gelatinizes through.

The method according to the present invention is characterized in that the fruit mash or puree which comprises dissolved calcium or aluminum ions, in the form of drops, is brought into contact with an alginate or pectasol so that a skin or film of calcium or aluminum alginate or - pectajel as the surface of the drop while the fruit pulp or puree in the interior of the drop remains ungelatinized.,

The encapsulated fruit material may, especially when the texture of a soft fruit is desired, contain a thickening agent which is preferably a water-soluble cellulose derivative, e.g. carboxymethyl cellulose. This means that the gel skin quickly thickens and becomes practically impermeable to the sun, so that reaction between the sun and the dissolved calcium or aluminum ions in the interior of the drop cannot take place.

The material to be encapsulated is preferably brought into contact with the alginate or hectate sol by releasing droplets of the material into a stream of the sol. The droplets are carried away, suspended in the flow, and can be recovered downstream in encapsulated form at a point (generally corresponding to an immersion time of 0.5" to 5' minutes) at which a gel skin of the desired thickness has formed on the droplets. The sun can then The surfaces of the recovered capsules will usually be quite sticky due to the excess sol on them', and it may therefore be desirable to gelatinize the sol on the surfaces by treatment, with a solution of an edible calcium or aluminum salt, this salt being conveniently the same as that used for the incorporation of dissolved calcium or aluminum ions into the original material subjected to the encapsulation process..

As for salts, calcium salts are preferred.

Examples of these are potassium acetate, citrate, gluconate, tartrate and acetate. If an aluminum salt is used, it can e.g. be aluminum sulfate or one of the edible alums.

e.g. potassium alum. A suitable concentration of load ■.'

calcium or aluminum salt, whichever is incorporated

1 the original material to be encapsulated, or i

the solution used during the treatment to counteract stickiness in the finished capsules is in the range of 0.5 to 2% by weight.

The alginate or pectate sol used is often based on an alkali metal alginate or sodium pectate, e.g. sodium alginate, ammonium alginate or sodium pectate. The preferred alginate or pectate concentration in the sol is 1 to 2% by weight.

As already mentioned, the invention has particular application to the production of fruit whose texture imitates the texture of blackcurrants and similar soft fruits whose skin encloses a relatively soft interior. Suitable fruit materials include mash or purée of blackcurrants, strawberries, apples, pears and peaches. Especially in the relatively mild materials such as apples/ these can be added. extra taste, as the taste does not necessarily correspond to the fruit in the mash or puree. Thus, applesauce can be flavored with blackcurrant flavor and encapsulated so that it forms products that resemble blackcurrant in both taste and texture. On the other hand, as illustrated in Example 2 further on in the description, strawberry mash or puree can be encapsulated to form artificial fruit with a texture that mimics blackcurrants but has a strawberry flavor.

The fruit substitutes produced according to the invention can, if desired, contain additional coloring material. If an edible color is added to the alginate or pectate sol used to form the fruits, then the fruit that is formed will have a. colored skin, while if the coloring matter is added to the edible material to be encased, the inside of the fruit will be colored...

The alginate or pectate gel skin on the fruit substitutes can act as a semi-permeable membrane, and when the fruit is stored in aqueous environments with a low content of dissolved salts,

it will tend to absorb water and swell. As it swells, it develops a texture which, in terms of the sensation it gives when bitten into, is very similar to natural fruit.

Presence of excessively watery texture in the interior

of the fruit can be avoided by adding a thickening

material .in fruit materialf which1 is to be encapsulated. The thickening agent :.sora can be used, can advantageously be one whose thickening properties. developed only by heating. A suitable thickener of this type is t<y>errbundét starch.-

When using such a thickener, you avoid making fruit food so viscous that drops are not easily formed from it, while the fruit substitute is allowed to develop a desired consistency after the heating that accompanies canning or pasteurization. Such a thickener can, if desired, be used in conjunction with an ordinary cold-acting thickener, e.g. carboxymethyl cellulose or a pregelatinized starch, to help provide a desired viscosity both in the material to be encapsulated and in the fruit substitute formed from this..

By careful, control to ensure uniformity

in the material to be encapsulated and in the volume ^v the droplets in it brought into contact with the alginate or .pectate sol. can the method according to the invention be used to give small and uniform quantities of a material in capsule form. • Flavor^ substances which are encapsulated according to. the invention, can be mixed into foodstuffs, e.g. in ice cream, vanilla cream, cakes or gel, to achieve a localized concentration of aroma.

The accompanying drawing is a diagram showing an apparatus suitable for carrying out the method according to the invention. •

A reservoir 1 for the material to be encapsulated is connected by means of a. tube with a peristaltic pump 3. A tube 4 exits from the pump and ends in a nozzle 5 (diameter suitable 1 to 3 mm) which is placed in the wide opening part of the spiral tube 6. A supply line 7 for the alginate or pectate sole opens also out into the wide opening of the spiral tube 6. Just below the outlet of the spiral tube there is a fine mesh screen 8 below which a reservoir 9 is located, for sun passing through the screen. The reservoir is connected to the supply pipe 7 via a pump 10. By it; lower end of the sieve 8 is a bath 11 which contains a solidifying solution of calcium or aluminum salt...

In operation, the material to be encapsulated is pumped from the reservoir 1 and emerges from the nozzle 5 in the form of droplets which fall into the alginate or pectate sol flowing from the supply pipe 7, down onto the inclined base in the wide opening of the spiral tube. The drops are carried by the sun as it flows into and through the entire spiral tube. When the droplets released from the nozzle 5 first come into contact with the sun,,, f ears. reaks ion • between the sun and the dissolved. calcium or... aluminum ions which are added to the material to be encapsulated, to form a thin. shell of gelatins.t alginate or pectate sol on the surface of the drops. The shell thickens as the drops

passes along the tube 6 in suspension in the sun. At the outlet of the pipe 6, the sole containing the suspended encapsulated material falls onto the sieve 8, which retains the capsules, ■• but allows the sole to pass through the meshes to the reservoir 9 for recirculation to the supply pipe. 7-. An air blower can be used to blow excess solar from the surface of the capsules while they are on sight. The encapsulated material rolls down onto the sieve 8 and into the solidification bath 11, from which, after a few minutes of immersion, it can be recovered and dried so that it is free of adhering, edible calcium or aluminum salt solution.

In the following, the invention will be illustrated by means of examples.

EXAMPLE 1.

This example shows the production of blackcurrant puree from blackcurrant substitute' with a shell of calcium alginate gel which is similar to the shell of real blackcurrants and has a blackcurrant fruit inside, and which is suitable for mixing into such products as yoghurt, pie filling and jam.

A viscous blackcurrant mash mixture containing calcium ions was prepared "by mixing together the following ingredients:

This mixture was placed in reservoir 1 of the apparatus illustrated in the drawing, and an alginate sol containing 2% by weight of sodium alginate, adjusted to pH 4 by means of citric acid, was circulated through the spiral tube in the apparatus.

The blueberry moss mixture was then pumped to the nozzle 5, and the drops of the moss that fell into the alginate sol were encapsulated and carried

through the spiral tube of the sun. They were later separated from the alginate sol on sieve 8 after they had been in contact with the alginate sol for approx. 1 minute. At this point (before they fell into the solidification bath 11) the droplets had formed a skin strong enough to withstand handling, but this skin was very sticky due to ungelatinized sol on the surface. Stickiness was not visible in the capsules collected from solidification bath 11 which contained a 2% by weight solution of calcium lactate in water.

Some of the artificial blackcurrants were mixed into yogurt while stirring to form a product that was indistinguishable from a yogurt containing real blackcurrants.

Others of the artificial blackcurrants were canned in an aqueous syrup and heated at 100°C for 30 minutes so that they would be sterile. Upon opening a can, the interior of the blackcurrants was found to have a thicker texture than before canning, due to the action of heat on the cross-linked starch. The texture of the blackcurrants after canning and sterilization resembled the texture of real blackcurrants to a far greater extent than before canning.

A further sample of the artificial blackcurrants was air-dried in a vacuum oven at 70°C for 90 minutes. The dried artificial blackcurrants were then mixed together with sugar, pectin, starch and dried blackcurrant puree into a dried pie filling which could be rehydrated into a product very similar to a pie filling made from natural fruit.

EXAMPLE 2.

The procedure from example 1 was followed using the same ingredients, but with the exception that the blackcurrant mash was replaced with strawberry mash. The fruit substitute capsules that were produced had a blackcurrant texture and strawberry flavour. When mixed into yogurt, they gave it not only a pleasant strawberry taste, but also an attractive texture.

Claims (1)

Process for producing a fruit product comprising fruit puree or fruit puree encapsulated in a skin or film of calcium or aluminum alginate or pectate gel, characterized in that the fruit puree or puree comprising dissolved calcium or aluminum ions, in the form of drops, is brought into contact with an alginate - or pectate sol so that a skin or film of calcium or aluminum alginate or pectate gel forms on the surface of the drop while the fruit mash or puree in the interior of the drop remains ungelatinized.