Food or edible material: processes – compositions – and products – Fermentation processes – Of plant or plant derived material
Reexamination Certificate
1998-12-24
2001-03-06
Pratt, Helen (Department: 1761)
Food or edible material: processes, compositions, and products
Fermentation processes
Of plant or plant derived material
C426S028000, C426S049000, C426S093000, C426S094000, C426S102000, C426S292000, C426S293000, C426S656000
Reexamination Certificate
active
06197353
ABSTRACT:
BACKGROUND
Egg wash is typically used as a baking gloss for enhancing the appearance of breads, pies, cakes and other baked goods. However, with the growing concern of Salmonella contamination of processing equipment and food, alternative compositions that provide good gloss finishes on edible substrates are desirable.
SUMMARY OF THE INVENTION
The present invention relates to methods of forming colloidal dispersions containing microparticles of gluten-derived protein and/or peptides. The colloidal dispersions can be maintained as stable, homogeneous dispersions under storage conditions (e.g., ambient, cold or frozen) without microbial contamination. Alternatively, the colloidal dispersions can be dried and rehydrated prior to use.
Colloidal dispersions of the present invention, when cast onto a substrate, form a glossy coating when dried at ambient or elevated temperatures. The films can further serve as an adhesive for adhering particulate material (e.g., seeds, salts, spices, confections, fruit) onto the substrate. Suitable substrates include but are not limited to confections, cooked and dehydrated meats, dessert items, snack foods (e.g., pretzels, chips, tortillas), fried foods (e.g., french fries), candies (e.g., chocolates), fruit (e.g., apples), vegetables, cereals, baked goods, seeds, nuts, beans (e.g., coffee), pharmaceuticals (e.g., vitamins and tablets) and paper.
Edible coatings produced by the present method are clear films which are non-toxic since they are derived from gluten from wheat, corn, rye, barley, rice or sorghum. The colloidal dispersions of the present invention do not contain toxic organic solvents or require extreme pH's, thus, the residues of these undesirable elements are minimized or eliminated.
DETAILED DESCRIPTION OF THE INVENTION
The invention pertains to aqueous colloidal dispersions of gluten-derived proteins and peptides, which when coated onto a substrate will impart a glossy coating thereon. The invention further pertains to methods for making the aqueous, gluten-derived colloidal dispersions, to methods for using the gluten-derived colloidal dispersions as baking gloss, for example, and to edible coatings on various substrates, included foods, pharmaceuticals and papers. The invention further pertains to methods for adhering edible particulate material (e.g., seeds, spices, candies, nuts) onto the surface of a substrate using the colloidal dispersions described herein.
The term “colloidal dispersion” as used herein means a suspension of microparticles of gluten-derived proteins and peptides having a median volume diameter of about 10 microns or less in an aqueous medium. Preferably, the gluten-derived microparticles will be from about 4 to about 5 microns and should be essentially free of starch. The terms “stable” and “homogeneous” as used herein define colloidal dispersions in which substantially all the microparticles of gluten-derived proteins and peptides can remain uniformly dispersed within the aqueous medium for an indefinite period of time under storage conditions, without irreversible precipitation or agglomeration.
Gluten useful in the methods of this invention is found in high concentrations in various grains, such as wheat, corn, rye, barley, rice and sorghum, and in other plant sources. Natural wheat gluten and vital wheat gluten are particularly preferred in the methods of this invention.
In one embodiment of the invention, an aqueous colloidal dispersion of gluten-derived proteins and peptides can be prepared by first dispersing gluten in an aqueous medium at a temperature sufficient to hydrate the gluten. Preferably, gluten is added to water which has been heated to a temperature sufficient to gelatinize starch in the gluten in the aqueous medium, under agitating conditions. A preferred temperature for adequate dispersion is from about 65° C. to about 85° C. As the gluten becomes dispersed within the aqueous medium, the viscosity of the dispersion increases. Therefore, the amount of gluten that can be dispersed in the aqueous medium will be dictated by the desired viscosity and the further processing steps described herein. For example, the amount of gluten which can be dispersed in the aqueous medium will be from about 1% to about 16% solids, with from about 12% to about 15% being most preferred. When adding gluten in the higher solids range, gradual addition of gluten into the aqueous medium is desirable, and will be described in detail below. For purposes of the present invention, “aqueous medium” is defined as water or a solution which is substantially water such as buffer, acid, antioxidant, reducing agent, and/or chelating agent solutions. It is preferred that the aqueous medium, such as water, be pretreated to remove dissolved minerals.
In order to facilitate dispersion of gluten, it may be desirable to acidify the aqueous medium to a pH of from about 3 to about 4 using organic and/or mineral acids (e.g., acetic acid, tartaric acid, citric acid, lactic acid, phosphoric acid, hydrochloric acid and others) with acetic acid and phosphoric acid being preferred. The acid can be added to the aqueous medium prior to, during or after addition of the gluten. The viscosity of the dispersion can be controlled by gradual addition of acid to the dispersion early in the reaction. See Example 4.
The aqueous colloidal dispersion of gluten is heated to a temperature sufficient to gelatinize the starch contained in the gluten such that it can be hydrolyzed in a subsequent treatment step. Preferably, the temperature is from about 65° C. to about 85° C. The gelatinization step should be carried out for from about 10 minutes to about 60 minutes to render all of the starch available for subsequent hydrolysis since the end desired product should be essentially free of starch. The presence of starch significantly reduces the gloss properties of the product and therefore its removal is important. The term “gelatinization” or variant thereof is intended to embrace the generally recognized term but also is intended to encompass the process of rupturing essentially all starch granules present in the starch, thereby releasing amylose and amylopectin. For the purpose of the present invention, the term “solubilize” refers to the absence of any detectable particulate matter, especially partially disrupted starch granules, when viewed under 200 to 400-fold magnification using a standard light microscope.
Next, the gluten-derived colloidal dispersion is cooled to a temperature suitable for enzymatic hydrolysis of the starch contained in the gluten. The purpose of this step is to completely digest the starch to glucose or maltose. The starch hydrolyzing enzyme is an enzyme containing glucoamylase, amylose, pullanase or combination thereof. A preferred enzyme is a glucoamylase, such as Optidex L-300 (Genencor International, Rochester, N.Y.) and AMG (amyloglucosidase; Novo Nordisk). The starch hydrolysis step is carried out for a period of time sufficient to remove essentially all starch from the colloidal dispersion and under conditions operative for the glucoamylase. Preferably, the temperature is near the optimum for the given glucoamylase. The amount of starch removed or hydrolyzed can be ascertained using the modified iodine assay described in detail below in the Examples section.
The resulting aqueous dispersion is treated, under agitation, with a protease to hydrolyze protein contained in the dispersion. A suitable protease is one which is operative at acid pH of from about 1.5 to about 5.5, for example acid fungal protease, such as but not limited to AFP 2000 (Genencor International, Rochester. N.Y.; food grade acid fungal protease obtained by a controlled fermentation of
Aspergillus niger
var.; optimum pH of from about 2.5 to about 3.5 at 37° C. according to the manufacturer). The protein hydrolysis step should be carried out for a period of time suitable to achieve a drop in viscosity and provide gloss. Preferably, the protein hydrolysis reaction should be carried out for about 2 to about 3 hours in order to achieve adequate viscosi
Crosby Guy A.
Iyengar Radha
Mallee Francis M.
McGowan Paul J.
Porcella Catherine F.
Hamilton Brook Smith & Reynolds P.C.
Opta Food Ingredients, Inc.
Pratt Helen
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