A dry hydrocolloid powder with cold-gel capabilities is produced by: dissolving a hydrocolloid comprising polysaccharide chains in an aqueous solution; heating the dissolved hydrocolloid solution to a temperature and for a time sufficient to induce a substantial alteration in the tertiary structure of the polysaccharide chains of the hydrocolloid; cooling the dissolved hydrocolloid solution to a temperature and for a time sufficient to substantially return the polysaccharide chains of the hydrocolloid to their original tertiary structure, wherein the polysaccharide chains form a gelling network; and drying the cooled hydrocolloid solution to form a dry powder. In some embodiments, the dry powder has a viscosity of between about 10 and 40 mPa-s when reconstituted in a 2% weight/weight solution at 25 degrees C. In other embodiments, the dry powder has a water absorption of greater than 20 g H₂O/g powder.

SUMMARY OF THE INVENTION

The present invention can provide a cold-gelling hydrocolloid product that may be used advantageously to thicken foods such as puddings, ice cream, milk shakes, custards, gels and the like. As a first aspect, the present invention is directed to a dry hydrocolloid powder with cold-gel capabilities. The powder is produced by: dissolving a hydrocolloid comprising polysaccharide chains in an aqueous solution, the polysaccharide chains having an original tertiary structure; gelling the dissolved hydrocolloid solution under conditions sufficient to form a gelling network; and drying the hydrocolloid gel network to form a dry powder. In some embodiments, the dry powder has a solution viscosity of between about 10 and 40 mPa-s when reconstituted in a 2% weight/weight solution at 25° C.

As a second aspect, the present invention is directed to a dry hydrocolloid powder with cold-gel capabilities. The powder is produced by: dissolving a hydrocolloid comprising polysaccharide chains in an aqueous solution; heating the dissolved hydrocolloid solution to a temperature and for a time sufficient to induce a substantial alteration in the tertiary structure of the polysaccharide chains of the hydrocolloid; cooling the dissolved hydrocolloid solution to a temperature and for a time sufficient to substantially return the polysaccharide chains of the hydrocolloid to their original tertiary structure, wherein the polysaccharide chains form a gelling network; and drying the cooled hydrocolloid solution to form a dry powder. In some embodiments, the dry powder has a viscosity of between about 10 and 40 mPa-s when reconstituted in a 2% weight/weight solution. In other embodiments, the dry powder has a water absorption value of greater than 20.0 g H₂O/g powder when reconstituted in an excess of distilled water. Carrageenan is a particularly suitable hydrocolloid. These powders can be added to ingredients of edible food products to increase the viscosity thereof.

As a third aspect, the invention is directed to a process for producing a dry powder. The process comprises: heating a dissolved hydrocolloid solution to a temperature and for a time sufficient to induce a substantial alteration in the tertiary structure of the polysaccharide chains of the hydrocolloid; cooling the dissolved hydrocolloid solution to a temperature and for a time sufficient to substantially return the polysaccharide chains of the hydrocolloid to their original tertiary structure, wherein the polysaccharide chains form a gelling network; and powdering the cooled hydrocolloid network to form a dry powder.

As a fourth aspect, the invention is directed to a process for thickening an edible food product, comprising: heating an aqueous hydrocolloid solution to a temperature and for a time sufficient to induce a substantial alteration in the tertiary structure of the polysaccharide chains of the hydrocolloid; cooling the dissolved hydrocolloid solution to a temperature and for a time sufficient to substantially return the polysaccharide chains of the hydrocolloid to their original tertiary structure, wherein the polysaccharide chains form a gelling network; and mixing the aqueous hydrocolloid network with the remaining ingredients of the edible food product, the aqueous hydrocolloid solution being included in an amount sufficient to increase the viscosity of the edible food product. This technique avoids the steps of powdering and reconstituting the gelled, cooled hydrocolloid.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described more particularly hereinafter. The invention is not intended to be limited to the illustrated embodiments; rather, these embodiments are intended to fully and completely disclose the invention to those skilled in this art. Like numbers refer to like components throughout, and certain dimensions and thicknesses may be exaggerated for clarity.

As described above, the present invention is directed to the use of a hydrocolloid-based thickening agent. As used herein, a "hydrocolloid" is intended to include any large molecular weight polysaccharide known to form a gel in water. Exemplary hydrocolloids include xanthan gum, guar gum, locus bean gum, tara gum, agar, furceltaran, sodium alginate, pectin, gum arabic, and carrageenan. Other hydrocolloids include carboxy-methylcellulose, methylcellulose, and hydroxypropylmethylcellulose,

As used herein, "carrageenan" is intended to include any of the family of linear sulfated food grade polysaccharides typically obtained from red seaweed. It is preferred that the carrageenan be provided in an extracted form. The carrageenan can be kappa, iota or lambda carrageenan, or a blend of two or three of these forms. Particularly suitable is a blend comprising kappa carrageenan and at least one of iota and lambda carrageenan. An exemplary carrageenan blend suitable for use with the present invention is SeaGel DP 437, a commercial blend available from FMC Corporation (Philadelphia, Pa.).

The hydrocolloids employed in embodiments of the present invention can be provided in solid form (such as a powder, cake, particle, or the like) or in solution (for example, as an aqueous solution), and can be produced in any production manner known to those skilled in this art. A suitable production technique for carrageenan is described generally in U.S. Pat. No. 6,063,915 to Hansen et al., supra.

According to embodiments of the present invention, the hydrocolloid is dissolved in an aqueous solution. As used herein, an "aqueous solution" is intended to mean solutions that include water as the predominant solvent. Also, the aqueous solutions may comprise distilled or deionized water, or alternatively may include ionic components (such as salts like sodium chloride or potassium chloride, preferably in a concentration of between about 0.1 and 2 percent) that may impact gelation. The aqueous solutions may be of a neutral, acidic or basic pH, with solutions having a pH of between about 6.0 and 8.0 being preferred.

The hydrocolloid is typically dissolved in the aqueous solution in a concentration of between about 0.01 and 10 percent by weight, and preferably in a concentration of between about 0.1 and 5 percent by weight, although other concentrations of hydrocolloid may also be suitable for use with the present invention. It may be desirable to enhance or expedite dissolution of the hydrocolloid through agitation or stirring of the solution.

The dissolved hydrocolloid solution is gelled. For some hydrocolloids, such as carrageenan, agar, furceltaran, pectin, gum arabic, xanthan gum, and locust bean gum, gelling follows a thermal mechanism, and is carried out by heating followed by cooling. For other hydrocolloids, such as sodium alginate and low methoxyl pectin, gelling is carried out by a chemical mechanism, so the addition of a chemical reagent (for example, calcium) causes gelation.

For thermally gelled hydrocolloids, the dissolved hydrocolloid solution is heated, typically to a temperature of between about 50 and 95 degrees C. (a temperature for carrageenan of between about 70 and 90 degrees C. is preferred). While not wishing to be bound by any theory of operation of the invention, the inventors believe that this heating causes the polysaccharide chains of the hydrocolloid, and in particular carrageenan, to disentangle from one another and substantially alter or denature their tertiary structure (for example, in the case of carrageenan, the helices of the carrageenan tend to at least partially uncoil). As used herein, "substantially alter" or "denature" means to sufficiently change the hydrocolloid solution so that a gelling network is formed in this or a subsequent step (such as cooling). Heating can be achieved through techniques known to those skilled in this art. This heating should be carried out for a duration sufficient to disentangle the polysaccharide chains, which is typically between about 1 and 120 minutes (depending on the size of the batch of solution), and may include stirring or other agitation, which can promote disentanglement.

After heating, a thermally gelled hydrocolloid solution is cooled, typically to or below its gelation temperature (in many cases, the hydrocolloid gelation temperature will be between about 0 and 60 degrees C., and for carrageenan the gelation temperature is typically between about 30 and 50 degrees C.). Cooling can be active (i.e., with chilling or refrigeration) or passive (i.e., the heated solution can be allowed to stand until it reaches the desired temperature). While not wishing to be bound by any theory of operation, the inventors theorize that cooling causes the polysaccharide chains of the hydrocolloid to substantially regain or return to their original tertiary structure, and the re-entanglement of the chains causes them to form a gelling network that is able to trap water. In the instance of carrageenan, the polysaccharide chains recoil into helices. The cooled hydrocolloid solution is typically maintained at temperature until subsequent processing (either powdering or addition into a recipe) occurs.

After cooling, in some embodiments of the invention, the hydrocolloid network is dried to form a dry powder. Drying can be carried out by any technique known to those skilled in this art to be suitable for producing a dry powder from a solution. Exemplary techniques include spray drying, freeze drying, grinding and crumbling. The dry powder may have virtually any particle size, although a particle size between about 1 and 10 μm is preferred.

The dry powder described above can be combined with other ingredients, such as emulsifying agents, stabilizing agents, anti-caking, anti-sticking agents and the like. Representative stabilizing agents are gums, certain proteins such as gelatins, and certain chemical derivatives of cellulose, and emulsifiers like lecithin.

The dry powder can be combined with a cold water-soluble protein to provide a thickening agent or fat substitute with both protein and carbohydrate components, depending upon particular dietary and cost considerations. See, e.g., U.S. Pat. No. 6,261,624 to Hudson et al., the disclosure of which is hereby incorporated herein by reference in its entirety. A cold water-soluble protein may be included in the dry powder in any suitable amount such as from 1 or 2 percent to 80 or 90 percent by weight to provide a combination protein and carbohydrate-based thickening agent or fat substitute.

The dry powder produced by the inventive process can have very desirable properties as a thickening agent. For example, when reconstituted in a 2 percent weight/weight solution in deionized water, a dry carrageenan powder can have a viscosity of between about 10 and 40 mPa-s at 25 degrees C. This viscosity can be raised with the addition of between about 0.1 and 2.0 percent of ionic components such as KCl. Also, the dry powder may have a water absorption value (as determined by the water absorption procedure described below) of greater than 20.0 g H₂O/g powder when reconstituted under those conditions. Once in powdered form, the carrageenan or other hydrocolloid powder can be easily stored for long periods in conventional sealed (i.e., airtight) containers.

The properties set forth above can enable the dry powder to be used as a thickening agent, even under cold-setting conditions. When used as a thickening agent, the powder is combined with the other ingredients of the food product in an amount sufficient to thicken or increase the viscosity of the food product (typically 1 or 2 percent to 50 or 60 percent by weight of the total weight of the product). The powder of the invention may of course serve multiple functions in a single food, as a binder, and/or thickening agent, to facilitate foaming, etc., and identification of one function herein is not intended to exclude that the ingredient is performing other functions.

The typical solid food product will constitute from 1 or 2 percent to 50, 60, or 70 percent by weight water (from all sources), or more. The typical liquid (including thickened liquid) food product will typically constitute 40 or 50 percent to 90, 95 or even 99 percent by weight water (from all sources). Other ingredients of a solid food product will typically constitute from 10 or 20 percent to 50, 60 or 70 percent by weight. Other ingredients of a liquid (including thickened liquid) food product will typically constitute from 1 or 2 percent up to 40 or 50 percent by weight, and occasionally more. These percentages are provided as general guidelines only; sometimes water is included in the weight of "dry" ingredients which are not fully dehydrated, and of course in no case do the total amounts of all ingredients exceed 100 percent, thus, it is preferred to define food products of the invention simply by reference to the amount by weight of the dry powder protein preparation added thereto.

The dry powder may be included in the preparation of cold-served foods, like chilled dairy products (such as ice cream, shakes, puddings, and custards), gelatins, salad dressings, processed meat and cheese products, jellies and jams, chocolate milk, syrups, pie fillings, dips, spreads, icings, and condiments. Alternatively, the dry powder can be used as a thickening agent for dysphagia patients to assist with swallowing.

In some embodiments, after cooling of the hydrocolloid solution, it may be added directly into foods during their preparation. This process can shorten the production cycle of such foods by eliminating the powdering process; however, the cooled solution may have a much shorter shelf life than the aforementioned dry powder.

Claim 1 of 21 Claims

1. A dry hydrocolloid product useful as a thickening agent, the product comprising a dry powder produced with a viscosity of between 10 and 40 mPa-s when reconstituted in a 2% weight/weight solution at 25 degrees C. produced by the process of:

dissolving a hydrocolloid comprising polysaccharide chains in an aqueous solution, the polysaccharide chains having an original tertiary structure;

gelling the dissolved hydrocolloid solution under conditions sufficient to form a gelling network; and

drying the hydrocolloid network to form a dry powder.

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