Gluten extraction method

Proteins have been studied for a long time. Beccari published an account of his experiments to isolate gluten in 1747 In 1805 Einhof discovered that a fraction of wheat gluten was soluble, while in 1858 Denis showed that many proteins of both plant and animal origin were soluble in saline solutions. In 1859 Ritthausen started to prepare highly purified proteins, only to be criticised by Weyl for using alkali to extract the proteins. Weyl in his work used the Denis method of extraction with neutral salts. 

Other workers used 0.1 m acetic acid for gluten separation then changed to dilute hydrochloric acid followed by neutralisation with sodium hydroxide.8 Byers et al. used 50% propan-l-ol in preference to 70% ethanol.9 Methods based on extraction with sodium dodecyl sulfate (SDS) have been developed by Danno10 as well as Graveland et al.11,12 Sonication of the SDS extract was introduced by Singh et al.13,14 Burnouf et al. introduced the use of dimethyl sulfoxide (DMSO) to remove monomeric proteins and a few small gliadins.15... 

With practice this method gives concordant results. As regards the extraction of the gluten, this is easy with fine wheat flour and ordinary bread flour, but difficult with inferior flours, and the latter may conveniently be manipulated under the water in a thin linen bag. Flours of other cereals do not yield gluten when treated in this way. 

Partial hydrolysis of proteins using acid, alkali or enzymes is commonly employed to improve functionality and usefulness of novel proteins. Acid hydrolysis is the most common method for preparing hydrolysates of soy, zein, casein, yeast and gluten. Hydrolysates are used in formulated foods, soups, sauces, gravies, canned meats, and beverages as flavorants and thickeners (2,3,6). Alkaline treatments have been employed to solubilize and facilitate protein extraction from soy, single cells, and leaves. 

Polymers derived from renewable resources (biopolymers) are broadly classified according to the method of production (1) Polymers directly extracted/ removed from natural materials (mainly plants) (e.g. polysaccharides such as starch and cellulose and proteins such as casein and wheat gluten), (2) polymers produced by "classical" chemical synthesis from renewable bio-derived monomers [e.g. poly(lactic acid), poly(glycolic acid) and their biopolyesters polymerized from lactic/glycolic acid monomers, which are produced by fermentation of carbohydrate feedstock] and (3) polymers produced by microorganisms or genetically transformed bacteria [e.g. the polyhydroxyalkanoates, mainly poly(hydroxybutyrates) and copolymers of hydroxybutyrate (HB) and hydroxyvalerate (HV)] [4]. 

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