A METHOD FOR PRODUCING AN ICE CONFECTION PRODUCT

Abstract: An effervescent ice confection product is obtained by exposing CO₂ - water clathrate-containing particles to such pressure, temperature and CO₂ and water partial pressure conditions that a protective layer will be formed on the particles, mixing said particles with a liquid phase containing ice confection ingredients and usually solid ice and having a temperature such that frozen water will not melt therein and thereafter decreasing the temperature of the obtained mixture to a usual storage temperature.

Description: The invention relates to a method of preparing a carbonated ice confection product wherein C0₂-water clathrate and a liquid aqueous phase which may contain solid ice are combined. A similar method is known from GB-A- 1 050 213. This method comprises combining an aqueous liquid, such as water and milk with a frozen "confection", consisting of a frozen dessert body, e.g. ice cream and a separate body of carbonated ice and preferably an amount of syrup containing sweetener and flavour. Upon contact with the liquid the carbonated ice will melt resulting in cooling the liquid and setting carbon dioxide free, which will partly escape and give the liquid effervescence. Thereafter the frozen dessert, flavouring and sweetener are stirred into the liquid. The product obtained in this way cannot be stored and should be consumed right after preparation as otherwise the effervescence will have ceased. The amount of carbon dioxide cannot be incorporated in a reproducible and controlled way into the final product using this method. An object of the invention is to provide a method with which the above problems may be lessened or even solved. To that purpose the invention provides a method as summarized hereinbefore which is characterized in that C0₂-water clathrate-containing particles are exposed to such pressure, temperature and CO₂ and water partial pressure conditions that a protective layer will be formed on the particle surface and these particles are mixed with the liquid phase which has a temperature such that frozen water would not be melted or dissolved overall in said liquid phase and afterwards the temperature of the mixture is lowered to a usual storage temperature for ice confection. The method of the invention provides an ice confection product comprising a mixture of liquid and solid water, sugar, flavour and, if required, stabiliser, emulsifier, protein, fat and air, having CO₂ - water clathratecontaining particles distributed therein. In US-A-4 398 394 likewise a method for preparing a carbonated drink is described, wherein a body of carbondioxide - water clathrate and ice and if desired flavouring matter and sweetening matter is put into contact with an aqueous liquid, whereby the ice is melted and the clathrate decomposed to liberate carbon dioxide. The resulting carbonated drink should be consumed within short as otherwise all carbon dioxide will have escaped. GB-A-1 095 004 describes a similar method for carbonating beverages and confections by adding briquettes, bars etc. of a carbonated ice product whereby the latter will dissolve to give a sustained evolution of carbon dioxide gas. The resulting product should be consumed right away as otherwise the effervescence will have gone. More of these prior art processes meets the aim of incorporating a reproducible and controlled amount of carbon dioxide into the product as most of it escapes before consumption. In this specification C0₂-water clathrate is meant to comprise any C0₂-containing clathrate such as double clathrates and mixed clathrates. For a better description thereof reference is made to D.W. Davidson; Clathrate Hydrates in water - A comprehensive Treatise; Vol. 2, Chapter 3, Ed. Franks. When producing an ice confection product according to this invention the liquid phase usually contains water-ice crystals before the clathrate-containing particles are added, which water-ice crystals are in equilibrium with the liquid phase and are forming therewith a slurry. This slurry may be obtained in a usual manner by feeding the unfrozen mix to a scraped-surface heat exchanger wherein it is cooled to a temperature of about -0 to -7°C or even lower. In practice it is to be preferred that the CO₂ - water clathrate-containing particles are exposed to such CO₂ pressure and temperature conditions, that CO₂ will evolve from the particle surfaces until a protective ice layer is formed, which for practical purposes prevents further CO₂ evolution under atmospheric conditions at temperatures below the melting temperature of ice. Usually this protective ice layer is formed within 15 seconds and consequently the stabilisation treatment is to be carried out for more than 15 seconds. A protective layer can also be formed around the CO₂ - water clathrate-containing particles by exposing these particles to a water-containing environment under such conditions that a layer of solid water condenses on the surfaces of the particles. This environment preferably comprises water vapour, which is condensed on the surfaces of the particles to form a solid protective ice layer thereon. Although the particle sizes of the clathrate-containing particles can be of the same order as the ice particles in the ice confection product to which the clathrate is to be added, in practice preferably particle sizes of from 200 to 2000 µm are used. By incorporating relatively large clathrate-containing particles, preferably having sizes in the range 0.2 to 1 cm, a product is obtained giving a peculiar sensation on eating. In this specification the term ice confection product is used in a broad sense, comprising products such as water-ice confection and ice-cream. The invention will be exemplified in the following examples. Example 1 An ice mix containing is cooled in a scraped-wall heat exchanger to -5°C to form a fluid slush product. In a pressurized reactor, CO₂, is contacted with water at a pressure of 35 bar and a temperature of 5°C. Thereafter the temperature is reduced to -15°C, such that the carbonated composite solidifies. After removal from the reactor, the clathrate-ice composite formed by this procedure is ground in a cooled mill to a particle size of 500-2000 µm. These clathrate-ice composite particles are exposed to the atmosphere for 30 seconds and thereafter 25 g of this particulate clathrate-water ice composite is added to 75 g of the slush product as described above. After mixing, the combined product is frozen to -20°C for storage. EXAMPLE II An ice mix containing is aerated and cooled in a scraped-surface heat exchanger to -6°C to form a creamy fluid. A clathrate-containing product prepared as described in Example 1 is ground to coarse particles and a sieve fraction from 1 to 5 mm is separated, stabilized as described in Example 1 and admixed in an amount of 50 g to 250 g of creamy ice fluid. This combined mixture is frozen to -20°C for storage.

Claims: A method of preparing a carbonated ice confection product wherein CO₂-water clathrate and a liquid aqueous phase which may contain solid ice are combined, characterized in that CO₂-water clathrate-containing particles are exposed to such pressure, temperature and CO₂ and water partial pressure conditions that a protective layer will be formed on the particle surface and these particles are mixed with the liquid phase which has a temperature such that frozen water would not be melted or dissolved overall in said liquid phase and afterwards the temperature of the mixture is lowered to an usual storage temperature for ice confections. A method according to claim 1, wherein the CO₂ - water clathrate-containing particles are exposed to such CO₂ pressure and temperature conditions, that CO₂ will evolve from the particle surfaces until a protective ice layer is formed, which for practical purposes prevents further CO₂ evolution under atmospheric conditions at temperatures below the melting temperature of ice. A method according to claim 1, wherein the CO₂ - water - clathrate-containing particles are exposed to a water-containing environment under such conditions that a layer of solid water condenses on the surfaces of said particles. A method according to claim 1, wherein the liquid phase contains water-ice crystals before adding the clathrate-containing particles. A method according to claim 2, wherein the CO₂ - water clathrate-containing particles are exposed to atmospheric conditions at a temperature below the melting point of ice for at least 15 seconds. A method according to any one of the preceding claims, wherein CO₂-water clathrate-containing particles having dimensions in the range of 200 to 2000 µm are mixed with the liquid phase. A method according to any one of the claims 1 to 5, wherein CO₂-water clathrate-containing particles having dimensions in the range of 0.2 to 1 cm are mixed with the liquid phase.

Inventors: BEE, RODNEY DAVID
Applicants: UNILEVER NV, UNILEVER PLC
Application year: 1986
Main classification: A23G9
IPC codes: A23G9