MXPA98009858A - Manufacture of a congel food product - Google Patents

Abstract

A process is described for the preparation of a confectionery product, frozen, coated, by which an aqueous solution in the supercooled state is caused to freeze while being applied on at least part of the surface of a pre-frozen element of the product.

Description

MANUFACTURE OF A FROZEN FOOD PRODUCT TECHNICAL FIELD OF THE INVENTION The invention relates to the manufacture of a frozen food product and to the products obtained by this method.

BACKGROUND OF THE INVENTION The present invention relates to the improved methodology for preparing frozen confectionery products such as sorbet. In particular, the invention relates to the frozen confectionery products and their method of preparation. European Patent EP 710,074 describes a method for the preparation of a frozen confectionery product composed by cooling an ice cream core, for example with liquid nitrogen followed by the application of a sorbet layer thereto. The resulting product has an improved soft texture compared to traditional pudding products, however the methodology to obtain the product consumes the energy and requires the use of liquid nitrogen u. other means of strong cooling. For this reason there is a desire to find alternative methods that could lead to the preparation of frozen confectionery products. British Patent GB 2 251 863 describes the storage of alcohol liquors in supercooled state under specific pressures. After emptying the liquor in a glass, it freezes to a sorbet type shape. International Patent WO 92/20420 describes the solidification of a supercooled liquid by holding the liquid by ultrasound; Application PCT / GB95 / 02804 (not previously published) describes the preparation of a suspension of ice crystals by mixing two solutions which can be supercooled. US Pat. No. 3,894,159 describes the supercooling of a confectionery filling pqr below its solidification point, said filling being then injected into the cavity of an edible cover at superatmospheric pressure sufficient to make the filling flowable. This flowable filler is then allowed to solidify in the cavity. International Patent WO 95/26640 describes the process by which an ice confection and a melted, supercooled, fat-filled coating are co-extruded such that upon contact with the ice jam the coating solidifies. Typically the coating will contain from 20% to 85% of chocolate fat - International Patent WO 96/20883 discloses a two-component ice confection, which is composed by cooling an ice confection core below -15. ° C, preferably using a cryogenic liquid, then immersing it in a sorbet solution to form a layer of sorbet on the core. The hardening of the water layer then follows by means such as immersion in liquid nitrogen, hardening in a freezing tunnel at -40 ° C. US Pat. No. 5,356,648 describes a process for the manufacture of a frozen dessert that. it comprises a frozen dessert base and substantially continuous strips or strands of a solid, subanhydrous flavor composition contained therein. This process involves conditioning the flavor composition from a solid or semi-solid paste within a high viscosity semiliquid composition, which solidifies easily when in contact with the partially frozen dessert base. Surprisingly, it has now been found that composite frozen products containing sorbets or other high quality frozen aqueous solutions can be very conveniently produced by freezing a supercooled aqueous solution, while being put in contact with a previously frozen element. of the product. This is surprising, since until now it was believed that freezing of supercooled liquid was very difficult to control and could not be reproducibly carried out on a simple product scale. For example, International Patent WO 92/20420 describes a very specific freezing apparatus in which the supercooled liquid is frozen by means of ultrasound. In consecuense, in a first embodiment, the invention relates to a process for the preparation of a coated frozen confectionery product, by means of which an aqueous solution in the supercooled state is caused to freeze while being applied on at least part of the surface of a pre-frozen element of the product. For purposes of the invention, the term coated frozen confectionery product refers to a frozen product comprising a number of different frozen phases, at least one of which is made from a frozen aqueous solution applied to the surface of another frozen element. Examples of such coated frozen confectionery products are for example pudding-like products that contain an ice cream core which is at least partially coated with one. sorbet layer and. layered products containing for example alternating layers of ice cream and sorbet. The process for the preparation of the frozen confectionery product comprises the step of freezing a supercooled aqueous solution. By super cold it is understood that the solution is at a temperature below the point of suspension, but nevertheless it is still a solution. Examples of a supercooled system is an aqueous solution which has been cooled to a temperature lower than the melting temperature for the aqueous solution, without forming ice crystals.

Preferably the aqueous solution has a temperature that is at least 0.5 ° C below the melting point, more preferably greater than 1 ° C below the melting point, and even more preferably at least 1.5 ° C below the melting point. fusion. Preferably, the temperature is at least 0.1 ° C above the metastable limit, more preferably greater than 0.5 ° C, and even more preferably 1 ° C above the metastable limit. For purposes of the invention, the term "aqueous solution" refers to any system having a water level of more than 40% by weight, preferably greater than 45% by weight, more preferably greater than 50% by weight. Preferably, the water level is less than 99.5% by weight, more preferably less than 98% by weight, and more preferably less than 95% by weight. The aqueous solution can be a manufactured composition such as a sorbet, or a natural solution. Examples of suitable aqueous solutions are mixtures of ice cream, sucrose solutions, sugar solutions, vegetable extracts such as tea, fruit juice, vegetable juice, oil-in-water emulsions and sorbet solutions.

A preferred type of aqueous solution is a sorbet composition. In general, sorbet compositions will contain water with sugar in this or other sweeteners and other optional flavoring ingredients. Suitable levels of sweeteners depend on the type of sweetener and the desired sweetness, and may for example vary from 0.01 to 50% by weight. Frequently ingredients such as stabilizers, emulsifiers, buffering agents, colorants, etc. are also present. Each of these ingredients will generally be present in minor, eg minor, amounts of 2% by weight, for example 0.01 to 1% by weight. Water levels are generally 50 to 99.9% by weight, more generally 60 to 95% by weight. Water can be added as such or in other forms, for example as juice concentrates or concentrates. . Alcoholic beverages are not covered within the term sorbet solution. It causes the supercooled aqueous solution to freeze while it is in contact with a pre-frozen element of the product. This can be achieved by any suitable means, for example, by subjecting the liquid to a physical or thermal disturbance or a combination thereof.

Surprisingly, it has been found that in the production of frozen, coated confectionery products, there is no need for expensive equipment such as ultrasound or sonic equipment. The supercooled aqueous solution can be brought into contact with the pre-frozen element of the product by any suitable means, for example by coextrusion or immersion of the pre-frozen element into the supercooled aqueous solution. Particularly good results are obtained if the aqueous solution is brought into contact with a pre-frozen additional component of the frozen confection. For example, the aqueous solution can be sprayed onto a pre-frozen layer or core of the sorbet or ice cream. A most preferred embodiment of the invention involves immersing a pre-frozen core in a supercooled aqueous solution such as a sorbet solution. Surprisingly, this leads to a frozen confectionery product, composed of very high quality, which can be easily prepared at low costs. Surprisingly, the invention of a pre-frozen core can also be realized while the solution for ... pre-frozen sorbet is contained in a bath of considerable size. Contrary to what can be expected, the immersion of the core of the side inside the supercooled bath does not cause the complete bath to freeze. In general, in addition to the layer adjacent to the core, only small amounts of ice crystals will form; These tend to float towards the surface of the bath and can be conveniently removed. This method therefore allows the preparation of coated confectionery products having a smooth or smooth coating layer with excellent texture - without the need for complicated methods or molds. The pre-frozen component to which the aqueous solution is applied can be any pre-frozen element. Examples of suitable elements are frozen cores to which the supercooled aqueous solution is applied or the frozen layers on which the supercooled aqueous solution is applied. Preferably, the additional pre-frozen component is pre-frozen at a temperature that is below the metastable limit of the sorbet solution. Preferably, its temperature is at least 1 ° C below the metastable limit, more preferably at least 10 ° C. This effects rapid freezing of the aqueous solution. Preferably, the pre-frozen component is made of ice cream or sorbet. The coated products made according to the invention have a very interesting texture of the frozen aqueous solution. This texture is especially apparent when a supercooled sorbet solution is used as the aqueous solution. Although the applicants do not wish to be bound by any theory, it is believed that this texture is caused by the specific orientation of size and the interactions between the ice crystals in the frozen aqueous solution. In general, the phases of sorbets in the compound frozen products will be frozen at rest. This leads to elongated crystalline forms (dendrites), said crystals being aligned in a direction perpendicular to the cooling source. Also, products made in accordance with European Patent EP 710,074 provide a smooth coating layer, the coating layer having the presence of elongated crystals, aligned in a direction perpendicular to the ice cream core. This can be contrasted with products made in accordance with European Patent EP 500,940 which has a rough, rough surface coating, in the ice crystals present within the coating are elongated crystals which are not predominantly aligned in a certain direction. Frozen aqueous solutions which have been obtained from supercooled liquids provide a smooth or smooth coating, they show. even a characteristic structure of dendritic ice crystals which are not predominantly aligned in a certain direction. The level of alignment can be conveniently measured by determining the homogeneity index for the sorbet. For purposes of the invention the Homogeneity Index is the ratio of the ice crystals parallel to the cooling source and perpendicular to the cooling source. Sorbet phases that have been prepared from supercooled sorbet solutions are generally characterized by a homogeneity index of 0.5 to 2.0, more preferably 0.8 to 1.3. An appropriate method for determining the homogeneity index for the sorbet is described in example I.

Accordingly, a second embodiment of the invention relates to a frozen, coated confection containing a frozen aqueous solution, wherein at least part of the frozen aqueous solution has a homogeneity index of 0.5 to 2.0. Preferably, all the frozen aqueous solution is sorbet. Preferably, the complete frozen aqueous solution has a homogeneity index within the above range. A particularly preferred embodiment of the invention relates to a frozen confection comprising an ice cream core surrounded by a layer of soft sorbet, the solution for frozen sorbet has a homogeneity index of 0.5 to 2.0. By "soft" it is meant that the coating layer does not contain projections greater than 200 microns, preferably without projections greater than 150 microns and more preferably without projections greater than 100 microns, when measured using a three-dimensional imaging surface structure analyzer (Ne View 200 of Zygo). The supercooled aqueous solution can be prepared by any convenient method. A very convenient method involves contacting with a refrigerant, said refrigerant having a temperature just above the metastable limit of the aqueous solution, for example 0.1 to 0.5 ° C above the metastable limit. The invention will now be illustrated by means of the following examples.

Example 1 Determination of the homogeneity index The homogeneity index of the sorbet in the frozen frozen confections can be determined as follows in the use of Scanning Electron Microscopy.

Scanning Electron Microscopy (SEM) Preparation of the Mix 1). Before the preparation of the sorbet / ice cream sample, it was stored at -20 ° C. 2) The sample was removed from storage and cooled on dry ice at -80 ° C. 3) A block of 5 x 5 x 10 mm was cut from the sample, to include any interfaces between layers / coatings. The block was oriented to give faces parallel to the expected (conventional) direction of ice growth. 4) The block was mounted on a SEM plate using an owner's mounting medium (OCT) above the freezing point (to prevent melting). 5) The plate was immediately immersed in nitrogen at -210 ° C. 6) The plate was then mounted on a plate holder and placed in a CP2000 preparation chamber at a vacuum of 10 ~ 6 torr. 7) The system was heated to -98 ° C. The mixture was then fractured. 8) The sample was allowed to attack with acid in 90 seconds, before cooling to -110 ° C. 9) The surface was coated in Gold-Palladium (conditions: 4 x 10"1 bar of anhydrous argon, current of 6mA, covered by 20 seconds.) 10) The vacuum was left to recover until vacuum of 10" ° torr. 11) The sample was transferred to a scanning electron microscope JSM 6301F for examination at -158 ° C (other .. conditions, 5 V, working distance 38 μm).

When examining the image, the cooling source is identified. For example, if a sorbet coating is frozen on an ice cream in general, the ice cream core will be pre-frozen and will therefore function as the cooling source. At a distance of 400 μm from the cooling surface, a line is drawn parallel to the cooling surface and another line is more perpendicular to it. Starting from the point of intersection of the two lines over a distance of 200 μm (either parallel to the cooling surface or perpendicular, moving away from the surface) the number of visually detectable ice crystal surfaces is counted. The index of homogeneity at a certain point can then be calculated by dividing the number of crystal interfaces in the perpendicular line element by the number of crystal interfaces in the parallel line element. To calculate the homogeneity index of the sorbet, the measurement is repeated in a number of points (preferably at least 3, but in general less than 10) and the average result is taken.

Example 2 A pre-prepared ice cream with an inserted stick (composition: 8.1% by weight of butter fat, 7.7% by weight of skimmed milk powder, 15.25% by weight of sugar, 2.5% by weight of whey powder, 0.65% by weight of stabilizer and emulsifier, 0.54% by weight of color and flavoring, and the rest of water, conventionally produced with 60% overflow) was removed from a freezer by jet at -33 ° C. The ice cream was immersed in a liquid mixture (for example, ice crystals were not present) of sorbet (composition: 40% by weight of fruit puree, 18% by weight of sugar, 3.95% by weight of glucose equivalent powder) a dextrose 42, 0.2 wt.% stabilizer, 0.2 wt.% citric acid, 37.6 wt.% water - giving a solids total of 27.9 wt.%) for 30 seconds. A coating of the semi-solid sorbitor coated the inner core of ice cream. The product was then hung in a wind freezer (-33 ° C) for 20 minutes, and then stored -25 ° C. The immersion process was carried out with the mixture of water at two temperatures; + 2 ° C (comparison) and -5 ° C. The melting point of the sorbet was -3 ° C and the metastable limit was measured to be -7 ° C (for example, the mixture at -5 ° C was supercooled). The structure of the coatings was investigated using the Electronic Microscopy of Measurement. The preparation technique is described below in Example 1. The homogeneity index of the product formed from the supercooled immersion process was 1.1, while the homogeneity index of the conventional immersion process was 0. 3.

Example 3 As previously produced, the horizontal layer d, the ice cream with a thickness of 6 mm (composition: 8.1% by weight of butter fat, 7.7% by weight of skimmed milk powder, 15.25% by weight of sugar, 2.5% by weight weight of whey powder, 0.65% by weight of stabilizer and emulsifier, 0.054% by weight of color and flavoring and the rest of water, conventionally produced with 60% overflow) was maintained at -7 ° C.

A liquid mixture of sorbet (for example, without ice crystals present) (composition: 15% by weight of sugar, 0.35% by weight of stabilizers, 5% by weight of lemon concentrate, 0.3% by weight of citric acid, and the rest of water) is emptied on the horizontal ice cream layer; the thickness of the sorbet layer was 1-2 mm. A second layer of ice cream at -7 ° C was placed on the sorbet layer. The resulting layered product was placed in a wind freezer (-34 ° C) for 40 minutes, and then stored at -25 ° C. The emptying process was carried out with the sorbet mixture at two temperatures: + 4 ° C (comparison) and -4 ° C. The melting point of the sorbet mixture was -2 ° C (for example, the mixture at -4 ° C was supercooled).

Claims (9)

1. A process for the preparation of a frozen, coated confectionery product, whereby an aqueous solution in the supercooled state is caused to freeze, while being applied on at least part of the surface of a pre-frozen element of the product.

2. A process according to claim 1, wherein the pre-frozen element has a temperature below the metastable limit of the aqueous solution.

3. A process according to claim 1 or 2, wherein the aqueous solution is a sorbet solution.

4. A process according to any of the preceding claims, wherein the pre-frozen element contains an oil-in-water emulsion, preferably ice-cream.

5. A process according to any of the preceding claims, wherein the pre-frozen element is submerged in the supercooled aqueous solution.

6. A process according to any of the preceding claims, wherein the supercooled aqueous solution is sprayed onto the pre-frozen elements of the confectionery product.

7. A coated frozen confection containing a frozen aqueous solution, wherein at least part of the frozen aqueous solution has a homogeneity index of 0.5 to 2.0.

8. A frozen confection according to claim 7, comprising an ice cream core surrounded by a soft layer of sorbet.

9. A coated frozen confection according to claim 7 or 8, produced by the method of any of claims 1 to 6.