Purification of zein from corn gluten meal

• US 5,580,959 A
• Filed: 03/10/1995
• Issued: 12/03/1996
• Est. Priority Date: 12/26/1991
• Status: Expired due to Fees

• Current Assignee: OPTA Food Ingredients Incorporated (Sunopta Incorporated)
• Original Assignee: OPTA Food Ingredients Incorporated (Sunopta Incorporated)
• Inventors: Mallee, Frank M., Cook, Richard B., Shulman, Mark L.
• Primary Examiner(s): Russel, Jeffrey E.
• Application Number:
  US08/402,320
• Time in Patent Office: 634 Days
• Field of Search: 530/373, 530/374, 530/376, 530/412, 530/414, 426/656
• US Class Current: 530/373
• CPC Class Codes: A23J 3/18 from wheat
• CPC Class Codes: C07K 14/425 Zeins

Abstract

This invention pertains to methods for extracting and purifying zein, zein bodies, glutelins or destarched corn gluten from corn gluten meal by efficiently removing and recovering food grade pigments and starch hydrolysates, while discarding unwanted fractions. Corn gluten is subjected to the combination of enzymatic starch hydrolysis, alkaline treatment, alcohol washing and alcohol extraction to produce a substantially starch-free, deflavored and decolored zein which is suitable for use in foods and pharmaceuticals. An advantage of the process described herein is its use of food grade alcohol(s) to deflavor, decolorize and extract the zein from corn gluten meal. Purified zein and zein bodies have improved utility and functionality in a variety of existing and emerging food applications. Alternate products such as deflavored, decolored and destarched corn gluten, zein bodies or glutelins are also obtained by the methods of this invention and are useful as vegetable protein supplements. By-products of the invention such as yellow food pigments and starch hydrolysates can be further purified and/or used directly in various foods.

Claims

1. Edible, decolored and deflavored zein or zein bodies produced by a process comprising the steps of removing color and flavor impurities from corn gluten by treating corn gluten with alkali to remove fatty acids and corn oils contained therein and then with an aqueous alcoholic solvent having a concentration which does not substantially extract zein and zein bodies therefrom, thereafter changing the concentration of the alcoholic solvent to a concentration sufficient to separate the gluten into decolored and deflavored zein or zein bodies fractions that are free of corn oils, xanthophyll and fatty acids.

2. Edible, decolored and deflavored zein or zein bodies produced by a process comprising the steps of:

a) destarching corn gluten with a carbohydrate hydrolyzing enzyme under agitating conditions, sufficient to hydrolyze and remove starch contained therein;

b) treating the destarched corn gluten of step (a) with an alkaline buffer having a pH from about 7.5 to about 9 under conditions sufficient to remove fatty acids or corn oils contained therein;

c) selectively extracting pigments and flavor compounds from the destarched and alkaline treated gluten of step (b) with aqueous alcohol having an alcohol concentration that does not substantially extract zein or zein bodies;

d) separating the gluten into zein or zein body and glutelin fractions by extracting or fractionating the gluten of step (c) with aqueous alcohol solvent having an alcohol concentration sufficient to either solubilize the zein or fractionate zein bodies therein; and

e) recovering the separated zein or zein body fractions from the appropriate aqueous alcoholic medium to thereby yield decolored and deflavored zein or zein bodies containing zein therein that are free of corn oils, xanthophyll and fatty acids.

3. An edible, continuous film cast from an ethanolic solution or an aqueous dispersion containing decolored and deflavored zein of claim 2.

4. An ethanol solution containing edible deflavored and decolored zein of claim 2, which solution is suitable for use as an edible barrier coating.

5. An edible, decolored and deflavored zein that is suitable for use in a food or pharmaceutical application, and that is free of corn oils, fatty acids and xanthophyll.

6. A food product containing edible, decolored and deflavored zein, zein bodies or combinations thereof as a fat replacer or texturizer in the food product.

7. An aqueous suspension containing edible, decolored and deflavored zein bodies, which suspension is suitable for use as an edible barrier coating.

8. An ethanolic solution or aqueous suspension containing edible, decolored and deflavored zein, which solution or suspension is suitable for use as an edible barrier coating.

9. An edible, continuous film cast from an ethanolic solution or an aqueous suspension containing edible, decolored and deflavored zein.

10. An edible, continuous film cast from an aqueous suspension of edible, decolored and deflavored zein bodies.

11. Edible, deflavored and decolored zein bodies that are suitable for use in a food or pharmaceutical application.

12. A pharmaceutical product containing edible, decolored and deflavored zein, zein bodies or combinations thereof.

13. A food or pharmaceutical which is coated with edible, decolored and deflavored zein, zein bodies or combinations thereof.