This application is a continuation-in-part of a copending application entitled Dietary Fiber Composition, Method of Preparation and Use, filed on July 8, 1993.

Field of the Invention

This invention relates generally to dietary fiber compositions, methods of preparation of dietary fiber compositions and uses of dietary fiber composition and, specifically, to a dietary fiber composition including a water-soluble fiber, a water-insoluble protein and an acidulant, a method of preparing the dietary fiber composition and a use of the dietary fiber composition to preserve food.

Background of the Invention

All food products begin to deteriorate the moment they are picked if they are of plant origin or caught and/or slaughtered if they are of animal origin. This deterioration can be delayed, for example, by chilling the food product. Better methods of chilling are continuously being sought in order to better preserve the food.

Alternatively, some food products such as fruits can be preserved by dehydration. However, even dehydrated fruits will deteriorate or become bug infested unless treated with a suitable preservative

agent. Many presently available preservative agents, such as sulfites, cause allergic reactions in sensitive persons and are becoming more heavily regulated by the United States Food and Drug Administration.

Accordingly, it would be desirable to provide an improved method of preserving food that overcomes the drawbacks of the prior art.

It is, therefore, an object of the invention to provide an improved method of preserving food.

It is another object of the invention to provide a method of preserving food using a dietary fiber composition including at least one water-soluble fiber.

It is still another object of the invention to provide a method of preserving food using a dietary fiber composition including at least one water-soluble fiber, at least one water-insoluble protein and an acidulant.

It is yet another object of the invention to provide a method of preserving food using a dietary fiber composition including water-soluble fiber, zein and an acidulant.

It is even another object of the invention to provide a method of preserving dehydrated fruit.

It is a further object of the invention to provide a method of preserving freshly picked fruit and vegetables.

It is still another object of the invention to provide a method of preserving freshly caught fish.

It is still a further object of the invention to provide a method of preserving food by chilling using ice with a lowered melting point.

It is yet another object of the invention to provide a method of preserving food by chilling the food using ice including a dietary fiber composition with water-soluble fiber, water-insoluble protein and an acidulant.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

Summary of the Invention

Generally speaking, in accordance with the invention a dietary fiber composition including at least one water-soluble fiber, at least one water-insoluble protein and an acidulant is provided. The dietary fiber composition can be used to preserve food by applying the composition directly to the food or alternatively, the composition can be used in the production of ice used to chill the food.

The invention accordingly comprises the composition of matter possessing the characteristics, properties and the relation of constituents and the several steps and the relation of one or more of such steps with respect to each of the others thereof, which will be exemplified in the method hereinafter disclosed, and the scope of the invention will be indicated in the claims.

Detailed Description of the Preferred Embodiments

A dietary fiber composition including at least one water-soluble fiber, at least one water-insoluble protein and an acidulant is provided. The dietary fiber composition can be used to preserve food by applying the composition directly to the food is provided. Alternatively, the dietary fiber composition can be added to water that is used to make ice on which the food is preserved by chilling.

The dietary fiber composition includes a water-soluble fiber, a water-insoluble protein and an acidulant. The fiber can be any fiber that is water- soluble and generally recognized as safe (G.R.A.S.) for human and animal consumption by the U.S. Food and Drug Administration. In general, water-soluble fibers are plant-derived polysaccarides and related materials such as pectin.

Examples of water-soluble fiber that can be used to prepare the dietary fiber composition include, but are not limited to water-soluble cellulose derivatives, seaweed polysaccharides such as alginate and carrageenin, seed mucilaginous polysaccharides, complex plant exudate polysaccharides such as gum arabic, tragacanth, guar, pectin, ghatti and the like, and microbially synthesized polysaccharides such as xanthan gum. In a preferred embodiment, the water- soluble fiber is selected from guar, pectin, gum arabic and mixtures thereof.

The soluble fiber is present in an amount between about 90 and 99.5% by weight of the total composition, preferably in an amount between about 95 and 99% by weight.

Similarly, the protein can be any protein that is water-insoluble and G.R.A.S. In general, the protein is a prolamine. A prolamine is a cereal-derived protein that is insoluble in water, absolute alcohol or neutral solvents and soluble in dilute (80%) alcohol. Suitable examples of prolamines include, but are not limited to, corn-derived prolamine or zein, barley-derived prolamine or hordein and wheat-derived prolamine or gliadin.

The water-insoluble protein is present in an amount between about 0.5 and 10% by weight of the total

composition, preferably in an amount between about 1 and 5%.

In a preferred embodiment of the invention, the water-insoluble protein or prolamine used in the dietary fiber composition is zein. Zein is extracted from corn or maize. Zein forms odorless, tasteless, clear, hard and almost invisible edible films.

Sixteen amino acids have been isolated from zein including glutamic acid or glutamine, leucine, proline, alanine, phenylalanine, isoleucine, serine, tyrosine and asparagine. The remaining seven are present in amounts of less than 3% by weight. Of the eight amino acids that are necessary for protein synthesis in the human body, zein has virtually no lysine or tryptophan.

Zein is extracted from corn gluten by physical, as opposed to chemical, means. In whole corn zein occurs as a heterogeneous mixture of disulfide- 1inked aggregates. Commercial extraction results in a product with a molecular weight of 25,000 to 35,000. There is a high proportion of hydrocarbon group side chains and a high percentage of amide groups present with a relatively low amount of free carboxylic acid groups. Zein is commercially available from Freeman Industries, Inc. of Tuckahoe, New York.

In addition, relatively small, organic, food- grade acids or acidulants are used to lower the pH of an aqueous dietary fiber solution prepared using the dietary fiber composition. The acidulants also act to enhance the water dispersibility of the dietary fiber composition, i.e. to facilitate reconstitution of the dietary composition in water.

Suitable acidulants include, but are not limited to, citric acid, maleic acid, adipic acid, fumaric acid and the like. In a preferred embodiment, citric acid is used.

The acidulants are used in an amount between about 0.25% and 5% by weight of the composition, preferably in an amount between about 0.5% and 1% by weight. When used, the acidulant is added to the water of an aqueous organic solvent system prior to addition of the organic component.

The dietary fiber composition is prepared by dissolving the water-insoluble protein or prolamine in an aqueous organic solvent system to form a protein solution. The soluble fiber is added to the protein solution to form a fiber/protein solution. The solvent is evaporated from the fiber/protein solution to provide the dietary fiber composition.

The aqueous organic solvent system is a mixture containing at least one organic solvent in water. Suitable organic solvents include, but are not limited to, alcohols such as ethyl alcohol and isopropyl alcohol; edible glycols such as propylene glycol and certain polyethylene glycols; and, ketones such as acetone. In a preferred embodiment of the invention, the aqueous organic solvent system is either aqueous ethyl alcohol or aqueous isopropyl alcohol.

The desired ratio of water to organic solvent is dependent on factors such as the miscibility of the solvent in the water and the amount of protein to be dissolved. When the organic solvent system is aqueous ethyl alcohol or aqueous isopropyl alcohol, the amount of water generally ranges between about 10 and 25% by weight and the amount of alcohol generally ranges between about 75 and 90% by weight. More preferably, the amount of water in such systems is between about 12 and 15% and the amount of alcohol is between 85 and 88%.

The water-insoluble protein or prolamine is added to the aqueous organic solvent system in an amount between about 100 and 300gms of prolamine per liter of aqueous organic solvent system, more preferably in an amount between about 120 and 240gms per liter. The dissolution is carried out at a temperature between

about 20°C. (ambient room temperature) and about 60°C, preferably about 30°C. using conventional agitation methods to form a protein solution. Soluble fiber is then admixed with the protein solution to form a fiber/protein liquid mixture.

The fiber/protein liquid mixture generally contains between about 90 and 99.5% fiber and between about 0.5 and 10% protein based on the total weight of fiber and protein. More preferably, the fiber/protein solution contains between about 95 and 99% protein and between about 1 and 5% protein based on the total weight of fiber and protein.

It is important that the water-insoluble protein or prolamine thoroughly impregnate the soluble fiber particles during the process of admixing the soluble fiber with the protein solution. The aqueous organic solvent system used to prepare the protein solution should wet the soluble-fiber particles so that the hydrophilic soluble fiber particles are impregnated with the hydrophobic protein to form the fiber/protein solution.

The admixing process is carried out until a complete uniform mixture is attained. In general, the process is carried out at a temperature between about 20° and 60°C, preferably between about 20° and 25°C.

for a time period of between about 10 and about 30 minutes, preferably between about 10 and 15 minutes. The fiber/protein solution is agitated during the admixing process by conventional agitation methods including, but not limited to, manual shaking, mechanical shaking, magnetic stirring, mechanical stirring or a combination thereof.

Additives that promote impregnation may be added at any point during the admixing process. Suitable additives include, but are not limited to, edible detergents and emulsifiers. Exemplary additives are polysorbates, edible vegetable oils and egg albumin (egg whites) .

Additives may be used in an amount between about 0.25 and 5.0% by volume of the fiber/protein solution, preferably between about 0.5 and 1.0%.

Once the fiber/protein solution has been prepared, the solvent is evaporated to provide a dietary fiber composition. Any number of solvent extraction techniques may be used including, but not limited to, vacuum drying, centrifugation, evaporation, freeze drying, air drying, convection oven drying or a combination thereof.

It is preferred that the solvent evaporation technique be one that does not require the use of

excessive or prolonged heat that will oxidatively darken the product. Although oxidative darkening has little effect on the utility of the product as a dietary fiber composition, it may affect its appeal and desirablility. One preferred method of extracting the solvent is vacuum drying which safely removes and recovers the solvent while drying the product to provide the dietary fiber composition.

The following examples of preparation of the dietary fiber composition are presented for purposes of illustration only and are not to be construed to limit the scope of the invention described herein.

Example 1 _^

A 10% zein solution was prepared by dissolving 10 grams of zein (Freeman Industries, Inc.) in 90 grams of an aqueous isopropyl alcohol solution. The aqueous isopropyl alcohol solution contained 15% water by weight and 85% isopropyl al cohol by weight. Dissolution was carried out in a 500ml beaker and the so lution was initial ly stirred using a mechanical stirrer at a speed of over l O O rpm in order to ful ly wet the zein. Once al l of the zein was dispersed, the s tirring speed was reduced by about 1/2 for an additional f ive minutes to insure complete dissolution of the zein in the aqueous isopropyl alcohol solution. The ambient temperature was

maintained at 22°C throughout this procedure. Accordingly, a protein solution was provided.

Two hundred grams (200g) of milled guar powder (f ine-60 mesh, TIC GUMS, Belca p, MD) was slowly added to the protein solution with vigorous stirring using a mechanical stirrer at a speed of over lOOrpm. Manual stirring was started as the mixture thickened. Additional aqueous isopropyl alcohol was added as needed to attain a soupy appearance indicative of successful impregnation of the soluble guar particles by the zein solution. Agitation of this soupy fiber/protein liquid mixture was maintained for fifteen minutes.

The resulting fiber/protein solution was dried under reduced pressure of 0.05 atm. at a temperature of 60°C. using a lab-Line Duo-Vac vacuum oven manufactured by LabLine Corp., Melrose Park, IL. The resulting dried dietary fiber composition was a yellowish-beige color and was milled to a granular form.

Example 2.

A soupy fiber/protein solution was prepared as described in Example 1. After addition of the guar was complete, 20 grams of dried egg albumin (Henigson, Inc., White Plains, NY) was added and dispersed completely. The resulting product was dried under reduced pressure at 60°C. using a Lab-Line Duo-Vac vacuum oven. The

resulting dietary fiber composition was a yellowish- beige color and was milled to a granular form.

Example 3_

Fifty grams (50g) of citric acid was added to 0.675kg of water used to prepare 4.5kg of an 85:15 alcohol twater aqueous organic solvent system. 500g of zein was added to the aqueous organic solvent system in a suitable vessel. The aqueous organic solvent was kept in motion during the addition with the aid of a mechanical stirrer. Accordingly, a solution of 10% zein in aqueous alcohol was provided.

9.5kg of guar gum was added to the 10% zein solution with mixing in a Stokes Heavy Duty sig a-type blender. After about 30 minutes of continuous mixing, the mass was homogeneous, slightly tan and had a wet, sand-like consistancy. The mass was dried in an explosion-proof drier to yield a dietary fiber composition.

The dietary fiber composition provided in accordance with Examples 1, 2 and 3 is used to preserve food by dispersing the dietary fiber composition in water to form a dietary fiber solution and applying the solution to the food. Alternatively, the dietary fiber solution is frozen and the frozen dietary fiber solution is used to preserve food by chilling.

To carry out the preservation processes in accordance with the invention, the dietary fiber composition is added to water. In a preferred embodiment, the water is purified or cleansed. The water can be purified or cleansed, for example, by distillation.

The dietary fiber composition is added to the water in an amount between about 2 and 50 grams per gallon of water, preferably in an amount between about 2 and 10 grams per gallon.

The dietary fiber composition is thoroughly dispersed in the water to yield a dietary fiber solution. Dispersion is carried out with good mixing, for example, using a mechanical stirrer. The thoroughly dispersed dietary fiber solution is a homogeneous dispersion.

The homogenously dispersed dietary fiber solution can be used to preserve dried or fresh fruit. Suitable dried fruits include, but are not limited to, raisins, apricots, cranberries, blueberries, figs, apples, pears, peaches and the like.

When dried fruit is being preserved, it is preferable to heat the dietary fiber solution to a temperature between about 70° and 160°F (21° to 71°C) prior to dipping the dried fruit since the heated

dietary fiber solution will penetrate the body of the fruit more thoroughly.

Dried fruit can be dipped into the heated dietary fiber solution using any method that is sound and economical. In one embodiment, the fruit is dipped by placing the fruit in a plastic or wire mesh basket and dipping the entire basket into the dietary fiber solution. After dipping in the heated dietary fiber solution, the dipped dried fruit is examined to determine if there is excess gumminess on the surface of the fruit. If so, the dipped dried fruit may be dipped in fresh water as a rinse.

After dipping, the dried fruit is blown with strong clean air to remove large droplets of water. The blow-dried fruit is then ready for any additional steps that may be required in the manufacturing process.

Freshly picked fruits or vegetables destined for frozen packaging can also be treated with the dietary fiber solution in a similar manner. Such treatment is believed to retard the process whereby sugar in the produce turns to starch, a necrosis process that begins the instant the produce is picked.

When fresh produce is treated with the dietary fiber solution, the dietary fiber solution is chilled to a temperature of between about 32° and 45°F (0° and

8°C), preferably to a temperature between about 32° and 35°F (0° and 2°C). This cold solution can then be sprayed on the produce as it travels from the harvest area to the processing plant.

The dietary fiber solution can also be frozen. It has been found that the dietary fiber composition functions as a lubricant in the ice making process, thereby increasing the efficiency of commercial ice making processes by acting as a release additive that permits the ice to be more readily released from the molds in which it is made.

Furthermore, by depressing the freezing point of the ice, the keeping qualities of freshly-caught fish or freshly-slaughtered meat can be enhanced. This is also believed to be due to the action of the dietary fiber composition of the fish or meat.

The following example of the use of the dietary fiber composition to preserve food is presented for purposes of illustration only and is not to be construed to limit the scope of the invention described herein.

Example 4_

Two thousand grams (2000g) of clean water was heated to 140°F (60°C) in a two liter beaker equipped with a εtirrer. 5g of the dietary fiber composition

(0.25% by weight) was added to the vortex and stirring was continued until mixing was completed and a dietary fiber solution was obtained.

Dehydrated fruit was placed in a collander- type device and immersed in the water containing the dietary fiber solution for a few seconds. The collander of fruit was removed from the dietary fiber solution and drained.

The drained fruit was rinsed in cold clean water and spread on absorbent paper. Finally, the fruit was spread onto absorbent paper and blown dry with clean air to remove excess water droplets.

Accordingly, a dietary fiber composition including at least one water-soluble fiber, at least one water-insoluble protein and an acidulant is provided in accordance with the invention. A method of preparation of the dietary fiber composition and a use of the dietary fiber composition to preserve food is also provided. In a preferred embodiment, the water-insoluble protein is zein.

The dietary fiber composition is dissolved in water to form a dietary fiber solution. The solution is used to preserve dehydrated fruit by heating the solution and dipping the dehydrated fruit into the heated solution.

Alternatively, the dietary fiber solution can be cooled and applied to fresh fruit or vegetables. This will enhance the keeping qualities of the fresh fruit or vegetables as it is transported from the area where it is harvested to an area where it is used or processed.

Alternatively, the dietary fiber solution can be frozen. The dietary fiber composition functions as a release agent permitting the ice to be more readily released from the molds in which it is made. In addition, the dietary fiber composition in the ice depresses the freezing point of the ice and acts as a preservative of any freshly caught fish or meat stored on the ice.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the described product, and in carrying out the above process, and in the construction set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and

specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Particularly, it is to be understood that in said claims, ingredients or compounds recited in the singular are intended to include compatible mixtures of such ingredients wherever the sense permits.