Zein solubilization

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. 

Individual Improvement of Lysine, Threonine, and Tryptophan Levels of Zein. Aso et al. (71) incorporated individually the three essential amino acids, lysine, threonine, and tryptophan, in which zein is deficient. Commercially available zein was hydrolyzed with pepsin to solubilize 90% of the protein. A 10 1 (w/w) mixture of the soluble hydrolysate and one of the ethyl esters of L-lysine, L-threonine, and L-tryptophan was incubated with papain in lOmM L-cysteine under the following conditions substrate concentration, 50% (w/v) enzyme-... 

The zein test developed by Gotte [6] is based on the solubilization by surfactants of a maize protein which is normally insoluble in aqueous solution, unless denaturated. The protein is incubated with the surfactant solution for 1 h, at a constant temperature and under slight shaking at the end of incubation, the soluble fraction is separated from the insoluble one by centrifugation and filtration. Solubilized zein is assayed. The more irritating the surfactant, the more zein will be denaturated and solubilized. 

Zein test Solubilization of a water-insoluble protein 6... 

Figure 1 Correlation between solubilized zein assay by Kjeldahl and BCA tests. Thirty mixtures of surfactants with different irritation potentials were tested by the two methods (according to Refe. 17 and 18) in order to establish the correlation existing between the two. All data were plotted on the figure in order to determine the correlation coefficient r, which is 0.98964.

Surfactants" Collagen swelling (percentage of swelling) pH rise (pH units) Zein test (percentage of solubilized Zein)... 

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