CZ214199A3 - Preparation of edible frozen articles - Google Patents

Abstract

The method of producing the gas hydrate is carried out so that it is filled container with some liquid water or frozen water, a certain amount of condensed gas is added, forming a hydrate into the container in such a manner that condensed gas does not come into contact with liquid water the condensed gas is contacted and / or it is provided sublimation or liquefaction products with appropriate pressure with a mixture of liquid or frozen water to form it the reaction mixture and maintaining the reaction mixture at or below the maximum temperature at which the gas hydrate is stable at a suitable pressure for a time sufficient to form a hydrate gas. Also included is a gas hydrate formed by this a method having a high gas content and a container (1) having parallel sides (8), detachable lid (5), base (6) and a platform (2) arranged centrally in the reaction vessel cavity (7). The platform (2) includes a support column (3) that extends upward from base (6) when container (1) upright. The compartment (4) is located on the pillar (3) in a suitable distance from the base (6) such that the compartment (4) is above the water placed on the base (6) of the container (1) when it is container (1) during use upright.

Description

Manufacture of edible frozen products

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The invention relates to the production of frozen products and more specifically to the production of edible solid gas hydrates for use in food products.

Various methods of producing hydrates of gas are known, for example from US-A-4,347,707, US-A-4,487,023 and US-A-3,217,503.

WO 94/02414 (EP 651 727) discloses a method for producing solid gas hydrates wherein the aqueous liquid as a continuous phase having dissolved hydrate forming gas therein is cooled to a sufficiently low temperature to form a solid gas hydrate.

All of the above methods require either careful control of reaction conditions or, more importantly, complicated and expensive equipment or conditions. In the methods of the aforementioned US patents, the composition of the final product cannot easily be predetermined, especially not in terms of higher gas concentration.

Conventionally, the gas forming the liquified or gaseous hydrate, i. CO ₂ , used in the preparation of gas hydrates, and then to deal with well-known safety and technical problems.

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The present invention solves these problems by providing a method for producing solid gas hydrates, requiring only a simple pressure vessel and utilizing conventional freezing equipment. Solid gas hydrates are particularly used in frozen food products.

Accordingly, the invention provides a method for producing a gas hydrate comprising the following steps:

(1) Filling the container with a certain amount of liquid water and • ftftft

(2) adding a certain amount of condensed hydrate-forming gas to the vessel in such a way that the condensed gas does not come into contact with liquid water, (3) contacting the condensed gas and / or its sublimation or liquefaction products at a suitable pressure with the liquid mixture; or frozen water so as to form a reaction mixture and to maintain the reaction mixture at or below the maximum temperature at which the gas hydrate is stable and at a suitable pressure for a time sufficient to form the gas hydrate.

The present invention also includes a gas hydrate produced by the method of the invention.

The method of the invention provides several advantages not previously associated with the production of solid gas hydrates. These benefits include low cost, large-scale or small-scale manufacturing flexibility, or full or partial automation or manual operation (even by one person only). Furthermore, the products have a high activity, i.e. large volumes of gas per unit weight.

Thus, the present invention provides an efficient but surprisingly simple method of producing gas hydrates using condensed hydrate forming gases, for example solid CO ₂ . This makes the process much easier for regulation and implementation. The above advantages have not yet been provided due to the difficulties encountered in handling the gaseous gases as conventionally used.

Ingredients and product

The gas hydrate to be produced can be any hydrate which can be produced according to this method, in particular gaseous CO2 hydrate. It is particularly preferred that the gas hydrate is CO ₂ gas hydrate. The condensed hydrate-forming gas used corresponds to the gas hydrate produced. The gas forming the condensed hydrate preferably comprises CO ₂ .

Water is used in the method of the invention. Purified or pure water is preferably used. Water may be added to the vessel either as liquid water or as frozen water. Preferably, a mixture of liquid and frozen water is added to the container, but it is possible to add only frozen water to the container and allow it to thaw in whole or in part. Alternatively, only liquid water may be added and the water may be wholly or partially frozen.

Where reference is made to gas hydrate, the term gas hydrate includes gas hydrate composites with ice.

The condensed hydrate-forming gas is used in this method in the form in which it exists at atmospheric pressure. For example, condensed carbon dioxide exists in solid form at atmospheric pressure and is thus used in this form. References herein to condensed hydrate-forming gas herein are to be construed accordingly. The condensed hydrate-forming gas will typically be in a solid state.

The method of the invention will be described in more detail below with reference to steps (1) to (4). It will be understood that within the scope of the invention one or more of the following steps may occur simultaneously or that the order of steps (1) and (2) may be reversed.

Step 1)

In the first step of the method, the vessel is filled with some • frozen water. Can be used ie. metered dose, pouring, quantity of liquid water each suitable method, filling by weighing etc.

liquid water surface condensed hydrate

In a preferred embodiment, the vessel is filled with a mixture of liquid water and frozen water such that the frozen water floats on. Prior to adding the gas forming to the vessel, the vessel preferably comprises a mixture of 10-80% by weight of frozen water in liquid water. -40%, eg 25-40%, based on the total amount of water.

If a mixture of liquid water and frozen water is used, the ratio of liquid water to frozen water (expressed as the above weight%) may be controlled to have an appropriate heat content so that the temperature in the vessel is stabilized at a value at least substantially all of the gas hydrate and at least substantially all of the ice was consumed. In other words, the reaction in the vessel largely regulates the heat itself, as long as the rate of ice is regulated within the limits set forth herein. The desired liquid water: frozen water ratio is obtained by using the above wt% frozen water in liquid water.

In one embodiment of the invention, a powdered, finely divided or granulated condensate hydrate-forming gas, for example solid CO ₂ , is added to the vessel containing liquid water and frozen water. Hydrate-forming condensed gas is preferred. In this way, an ice stopper is formed on the entire surface of the liquid water by the action of the solidified gas on the ice floating on the water and forms at least a substantially complete barrier across the cross-section of the container. The ice stopper is ideally designed as a solid ice stopper extending over the entire cross-section of the container. The ice stopper could also be formed by other methods.

• • •

The ice stopper barrier described above is one of the methods of achieving physical separation of liquid water and condensed hydrate forming gas as required in step (2). Other suitable methods to achieve separation can be used, and some other suitable methods are described below in step (2).

The filling as used herein does not necessarily describe where the container is filled to its volume. The container is usually filled to 65-90% of its volume, for example 75-90% of its volume.

Alternatively, the container may be filled only with frozen water in step (1) such that the use of condensed hydrate-forming gas to form an ice plug is not required.

The amount of liquid and / or frozen water is usually determined before the container is filled, so that the exact amount of each component is added. Alternatively, a calculated amount of the first component may be added and the amount of the second component calculated accordingly.

Step (2)

In a second step, a quantity of hydrate-forming condensed gas is added to the vessel in such a way that the liquid water and the hydrate-forming condensate gas do not come into contact, i. they are physically separated. It should be noted that the order of steps (1) and (2) can be reversed when water is added to the vessel only when frozen. Thus, the condensed hydrate-forming gas may in practice be added before, during or after step (1).

Physical separation of liquid water and condensed gas (if in solid form) can be achieved by any suitable method. Suitable methods include, for example, using a graduated inner diameter vessel in conjunction with a condensate hydrate-forming gas block (e.g. solid CO ₂ ) or attaching a condensate hydrate-forming gas block (e.g. solid CO ₂ ) to the container lid or forming compartments above the water surface.

In one particularly preferred embodiment, the condensed hydrate-forming gas is added to the container, preferably as a granule, so as to lie on the ice stopper (formed in the first step), thereby avoiding contact with liquid water until required. Preferably, the ice stopper has liquid water on one side and the condensate gas forming the hydrate on the other side so that the two components do not come into contact until they have melted the ice stopper or otherwise have lost their integrity.

In another embodiment, this separation can be achieved using a platform comprising a tray and a support post, wherein the tray is supported by a support post that extends from the base of the container to the upper surface of water (whether liquid, frozen or a mixture of both) in the container. When the container is upright, the compartment lies above the surface. The platform includes a support post detachable from the base of the container. Preferably, the compartment is concentric to the support post or is positioned to rest on the top of the post. The outer edge (cross-section) of the compartment may have any suitable shape, although in order to provide an effective physical barrier, it is preferred that the partition cross-section has a shape substantially consistent with the shape of the inner surface of the sides of the container. However, there must be a sufficient gap between the rim of the compartment and the inner surface of the vessel to allow proper mixing of the reaction mixture. The support post may extend above the tray to the container lid when the container is upright. In a container of the preferred type, the support post is preferably located centrally in the container cavity and extends from the base of the container to the lid. The platform can be • 4 4444 44 44 4 »44

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made of any suitable material, but preferably of a flexible material that is readily separated from a gas hydrate product (e.g., polytetrafluoroethylene (PTFE)). The platform must be capable of being detached from the container to allow efficient removal of the product.

According to this embodiment, the support column preferably forms a central ring in the reaction vessel. This provides the advantage of reduced processing time.

Before, during or after the condensed hydrate-forming gas is added by any method of performing the second step. Some amount of pre-foamed gas hydrate product may be added to induce nucleation of the gas hydrate product. Preferably, a finely divided, powdered or granulated pre-foamed hydrate gas product is added to the ice stopper formed in the first step. Pre-foamed

The hydrate gas product may be added at any time before the condensed hydrate-forming gas is contacted with the liquid water. The foamed hydrate product is preferably added to the ice stopper earlier than melting.

The condensed hydrate forming gas and the foamed gas hydrate product (if used) are supported by an ice stopper or platform tray and are kept physically separate from the liquid water. This allows the container to be securely sealed since the two components of the gas hydrate product have not yet been intimate.

The components are usually added at atmospheric pressure.

The weight ratio of the condensed hydrate-forming gas to the total frozen and liquid water is preferably within the range of < RTI ID = 0.0 > 9999 < / RTI >

in the range of 1: 2.35 to 1:11, preferably 1: 3 to 1:10, e.g.

1: 4 to 1: 7, such as 1: 5.5 for the preparation of a CO ₂ gas hydrate.

This corresponds to the molar ratios for CO ₂ to water from 1: 5.75 to 1: 26.9, preferably 1: 7.33 to 1: 24.5, i.e. 1: 9.8 to 20.5.

1: 17.1, such as 1: 13.4.

For other condensed hydrate-forming gases, the ratio of solidified gas to total frozen and liquid water is as above for CO ₂ .

The CO ₂ gas hydrate has the so-called structure I (SI). The above molar ratios are used to produce other SI gas hydrates according to this method. Tzv. The gas hydrate structure II (S1) may be prepared using gas to water and ice molar ratios that respect the stoichiometry of the gas hydrate S11.

At the end of the second step, the vessel is sealed to atmosphere before pressurization (usually by self-pressurizing as it sublimates solid CO ₂ and melts and boils at the appropriate temperature and pressure).

Step (3)

In a third step, the liquid water and the condensate gas forming the hydrate, or its sublimation or liquefied products, are allowed to come in or contact to form a reaction mixture. This occurs most preferably at a temperature that is at or below the maximum temperature at which the gas hydrate is stable.

The contacting to form the reaction mixture may be either by contacting the condensed gas or its sublimation products with either liquid water only.

5 or with a mixture of ice and liquid water. It includes that frozen water.

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When the liquid water and the condensed hydrate-forming gas are separated using an ice plug, the ice plug may be thawed by any suitable means, such as a heating mantle, warm air, hot water, etc., to bring the liquid water into contact with the condensed gas. Melting can be localized or occur by the general use of melting means. If the condensate hydrate-forming gas is supported on the platform compartment, there is no requirement to have the ice stop melted. In practice, an ice film is formed across the vessel that is not as thick as the ice stopper due to the conditions inside, but which melts easily.

The reaction mixture may be stirred by any suitable means, including rotation or by shaking the vessel about its axis or vertical axis.

The reaction to form a gas hydrate typically begins to appear in the third step of the method. The temperature of the reaction mixture in the vessel should not exceed the maximum temperature at which the gas hydrate is stable and is preferably in the range of 0 ° C to 5 ° C, more preferably 0 ° C - 2 ° C.

The temperature of the reaction mixture is maintained at or below the maximum temperature at which the gas hydrate is stable for a sufficient period of time to form a gas hydrate. Usually it is necessary to freeze or further cool the mixture.

The temperature of the reaction mixture may be lowered below the maximum temperature at which the gas hydrate is stable by any suitable heat dissipating means, for example a water bath or cooling jacket, in which the coolant such as brine and / or glycol is vaporized, for example ammonia. using a jacketed vessel or using conventional freezing (eg cold storage) or any conventional freezing method (eg air freezer).

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The gas hydrate product will generally be formed by subjecting the reaction mixture to quiescent freezing by placing the vessel in a freezer, for example an air freezing apparatus.

Removing the product

The completely solidified gas hydrate product may be removed from the container by any suitable means, for example heat applied to the outer surface of the container may be used to melt a portion of the product that contacts the heated portion of the container to aid removal. Suitable means for facilitating removal include the use of hot water, hot air or heating jackets on the reaction vessel. Alternatively, the product may be removed from the container manually or mechanically.

Other possible components

The edible gas hydrate product may be prepared to include a small amount of conventional frozen confectionery product as ingredients such as seasonings, colorings, etc.

Container

The vessel may be any suitable vessel capable of withstanding the pressure build-up that occurs during the reaction in which the product is formed from the gas hydrate, preferably the pressure vessel. It is particularly preferred that the container is standing freely and of a suitable size and shape so that it can be filled, movable and manually emptied, for example if a single person can do so.

A suitable vessel, and a vessel that is particularly preferred, has an elongated reaction chamber, for example a substantially cylindrical reaction chamber formed by a vessel having:

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1 9 9 19 · Long, narrow parallel sides. It is advantageous in terms of cost of the pressure vessel if it is substantially cylindrical. To optimize the surface for cooling and nucleation of reactions and to minimize costs, the vessel preferably has a high inner length to inner diameter ratio ranging from 3: 1 to 20: 1, preferably 7: 1 to 20: 1, most preferably 10: 1 to 15: 1 .

While substantially cylindrical containers are preferred for cost reasons, substantially cylindrical containers with an inner cone of up to 20%, with a base having a smaller inner diameter than the inner diameter of the container at its lid end are also included.

The container may be equipped with wheels (or something similar) to be movable, and is preferably capable of being reoriented in various ways, for example from a vertical position to a horizontal position. This reorientation can be achieved by any suitable means, such as a winch, levers, or any suitable automatic means. The container typically has a lid or other suitable closure means that can be tightened or loosened as desired, for example by screws.

Figure 1 shows a reaction vessel for use in a second embodiment of the method of the invention. The vessel (1) has parallel sides (8), a detachable lid (5), a base (6) and a platform (2) arranged centrally in the cavity of the reaction vessel (7). The platform (2) includes a support post (3) that extends upwardly from the base (6) when the container is upright. The compartment (4) is positioned on the post (3) at a suitable distance from the base (6) such that the compartment (4) is above the water located on the base (6) of the container (1) when the container is upright during use. The outer cross-section of the compartment (4) is preferably substantially consistent with the inner cross-section of the sides of the reaction vessel (8). Advantageously, the compartment (4) may be substantially horizontal. The post (3) is preferably arranged to provide an annular space in the product.

A variation of the container of Figure 1 has a platform (2) comprising a support post (3) and a compartment (4) arranged as in Figure 1, but the support post (3) does not extend above the compartment (4) when the container is upright.

An alternative container shape is one in which the container is angled or bent so that it is substantially V or C. In practice, however, this container shape has been found to be less suitable than the container described above because it is more difficult to remove the product from it. .

The method according to the invention is not expensive, simple and can be fully or partially automated. If desired, any part of the method can be automated.

Examples

The method of the present invention will be further illustrated by the following example. Other examples and modifications within the scope of this invention will be apparent to those skilled in the art. Following a general description of the invention, the following examples will be described to illustrate the preparation of a CO ₂ hydrate to illustrate the process of the invention, which can also be used to produce other desired gas hydrates.

The following examples also illustrate the claimed product.

Example 1 - Ice Stop Separation Method

The gas / ice hydrate composite product was produced as follows:

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A cylindrical pressurized vessel (mounted on a support on wheels) was charged with 7 kg of pure water and 4 kg of ice, so that the vessel contained a mixture of ice and water containing approximately 36% ice (before the ice melted). The ice floated on the surface of the water.

The floating ice was reinforced by spraying powdered solid CO ₂ (100 g) to lower the ice temperature and to form a solid ice stopper over the entire surface of the water.

An additional 2 kg of solid CO ₂ was added to the vessel. The solid CO ₂ was kept separate from the liquid water under the ice stopper, so at this point no reaction took place between the solid CO ₂ and the liquid water. Pulverulent products composed of C0 ₂ gas hydrate and ice (100 g), taken from a previous preparation, was sprayed onto the solid CO ₂ to ensure nucleation of the gas hydrate phase.

The lid of the pressure vessel was put in place and secured with nuts tightened to the required torque using a pneumatic tool. The container was sealed (by closing the tap on the lid) and manually moved from vertical to horizontal by rotating the container 90 degrees so that it rested on its wheels.

The sublimating CO ₂ cooled the portion of the container containing CO ₂ (i.e., the portion that was the top when the container was filled). Melting CO ₂ caused rapid cooling, and soon the vessel contained liquid CO ₂ at the top of the vessel during filling, an ice stopper and liquid water where the vessel base was.

Mixing of liquid CO ₂ and liquid water could begin after melting the ice stopper by applying warm running water to the outside of the vessel. Container (which has been balanced) · ·················· 6 · 6 Around the center of gravity) was gently shaken by hand to ensure sufficient mixing to mix the contents. At this stage, the vessel contained a suspension essentially of CO ₂ gas hydrate crystals in water.

The tank was allowed to stand for a few minutes and then transported to an air freezer where the contents were frozen. The vessel was then left at -35 ° C for 4 hours to freeze the contents. After the contents were left there long enough to freeze, the pressurized vessel was removed from the freezer and excess pressure in the vessel was released through the pressure relief valve before releasing the lid.

The open container has returned to an almost vertical position, but with the end having a lid downwards to allow removal of the frozen product. The hydrate product was removed from the vessel by rinsing the outer surface of the vessel with warm water so that the product was defrosted by melting the portion of the product in contact with the vessel.

The ratio of solid CO ₂ to water plus ice initially given into the vessel was chosen to produce the desired carbon dioxide content of the product consisting of a gas and ice hydrate, i.e. a water-to-ice ratio. in ml CO ₂ .g ^-1 .

The water to ice ratio was chosen to give the correct heat content to bring the reaction to completion.

The carbon dioxide content of the mixed product was 55 ml CO 2 g ^-1 . Products composed of gas and ice hydrate produced solely using dissolved CO ₂ typically contain up to 25 ml CO 2 g ^-1 . Thus, the method of Example 1 gives a gas hydrate having a carbon dioxide content greater than that of the dissolved gas method.

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Example 2 - separation platform method

Example 1 was repeated, but using a cylindrical pressurized container of Example 1, modified to include a platform comprising a support post and a compartment as shown in Figure 1. Using the container of Figure 1, an annular ingot is obtained from a product composed of a hydrate gas and ice.

The ice-water mixture of Example 1 was placed in the vessel to a level that was below the platform compartment when the vessel was upright.

Solid CO ₂ was added to the vessel so that it was not in contact with any liquid or frozen water. Powdered pre-expanded gas hydrate product C0 ₂ was sprayed into the solid C0 ₂ on the platform as in the Example 1.

The vessel was sealed and the reaction mixture shaped and stirred as in Example 1.

The method of freezing and removing the gas hydrate product was according to the method of Example 1.

The method of Example 2 gave an edible gas hydrate having an equivalent carbon dioxide content as in Example 1. It was found that Example 2 was particularly advantageous in terms of the required freezing time while still providing an acceptable amount of product per batch.

Claims (15)

A method for producing a gas hydrate comprising the following steps: 2) adding a certain amount of condensed hydrate-forming gas to the vessel in such a way that the condensed gas does not come into contact with the liquid The method of claim 1 or claim 2, wherein step (1) comprises filling the vessel with a certain amount of liquid water 25 and frozen water and adding a certain amount of powdered, finely divided or granulated condensed hydrate-forming gas to form an ice stopper over the liquid water. The method of claim 3, wherein in step (2) a quantity of condensed hydrate-forming gas is added to the ice plug formed in step (1). 4 4 4 4 4 5 44 44 44 44 container. A gas hydrate obtainable by the method of any preceding claim. 16. A reaction vessel having a base, parallel sides, and a removable lid that define a cavity of the vessel with a platform positioned centrally in the cavity, the platform comprising a support column extending upward from the base 4,444 4 4 4 · 4444 44 reaction mixture. 4 4 4 4 4 5 by placing it on a detachable platform above the level of frozen water and / or liquid water in the vessel. The method of any one of claims 2 to 4, wherein the step 35 (3) includes melting the ice stopper to contact the liquid water and the condensed hydrate forming gas and / or its sublimation / liquefied products to form • 4 •··· ··· 44 • 4 4 4 5 (1) filling the container with a certain amount of liquid water or frozen water, ( The method of claim 1, wherein in step (2) a quantity of condensed hydrate-forming is added to the vessel Method according to any one of the preceding claims, wherein a finely divided powder is added to the vessel in step (2) The method of any one of the preceding claims, wherein the condensed hydrate-forming gas is added to a container containing a mixture of 10-80 wt. % frozen water in liquid 15 water The method of any one of the preceding claims, wherein step (4) comprises freezing the reaction mixture. The method of claim 9, wherein the freezing takes place by placing the container in an air freezing apparatus. 10 when the container is erected and the tray positioned on the support post at a distance from the base such that the tray is at a height on the post that is above the reaction content of the container located at the base of the container. 10 or granulated pre-foamed gas hydrate. (3) contacting the condensed gas and / or its sublimation or liquefaction products at a suitable pressure with a mixture of liquid and / or frozen water so as to form a reaction mixture and maintain 15 of the reaction mixture at or below the maximum temperature at which the gas hydrate is stable and at a suitable pressure for a time sufficient to form the gas hydrate. The method of claim 1, wherein the condensed gas-forming hydrate comprises solidified carbon dioxide. The method of any one of the preceding claims, wherein the condensing hydrate forming gas is CO ₂ and by weight The ratio of condensed CO ₂ to total frozen and liquid water in step (2) is between 1: 2.35 and 1:11. The method of claim 11, wherein the molar ratio of condensed CO ₂ to total frozen and liquid water is 30 1: 5.75 to 1: 26.9. A method according to any one of the preceding claims, wherein the vessel has a longitudinal reaction chamber, preferably with a ratio of the internal length of the tank to the internal diameter of the tank of 3: 1, and 35 more. The method of claim 13, wherein the vessel is pressurized. 44 44 * 4 _ 1 Q _ · · O 44 4 4 »4 • 4 44 ·· • 4 · 4 The reaction vessel of claim 16, wherein the platform support post extends upwardly from the base to substantially the removable lid.