Extraction,Enzymatic Hydrolysis And Properties Of Corn Gluten

The corn gluten meal(CGM),a major by-product of corn wet milling, contains62-71%（w/w）proteins. Because of the poor solubility of CGM, the application of CGM wasrestricted. If a part of CGM produced was manufactured further to produce corn peptide, asfood and materials of foods, its value will be increased.The dissertation focuses on the extraction of alkali-dissolution and acid-precipitation ofextruded CGM, enzymatic hydrolysis of extracted gluten by Alcalase and Protamex, andproperties of hydrolysate of extracted gluten.(1)Extraction condition of Alkali-dissolution and acid-precipitation of protein fromextruded CGM was researched. Optimized extraction condition were concentration of sodiumhydroxide of0.55%(w/v), extracting time of110min, temperature of65℃and, ratio ofsolid-liquid of1:15. Under the optimized condition, the yield of gluten was50.12%. BySDS-PAGE, the gluten’s subunits molecular weight were mainly between14.4KDa and31.0KDa, a small amount of subunit between31.0KDa and66.2KD, and molecular weighthigher than66.2KDa was not found.(2)The suitable hydrolysis conditions of gluten catalyzed by Alcalase were glutenconcentration of3%(w/v), enzyme addition and gluten concentration ratio of2%(w/w),60℃,pH8.0, hydrolysis time of120min. Under the optimized conditions, degree of hydrolysis ofthe gluten and, soluble protein content were24.41%and10.02mg/ml respectively. Thesuitable hydrolysis conditions of gluten catalyzed by Protamex were gluten concentration of3%(w/v), enzyme addition and gluten concentration ratio of1.5%(w/w),50℃,pH6.5,hydrolysis time of120min. Under the optimized conditions, degree of hydrolysis of the glutenand, soluble protein content were17.94%and9.02mg/ml respectively. The molecular weightof hydrolysate by Alcalase was mainly distributed between838.49-160.69Da, which wasabout53.92%.（3）The properties of hydrolysis of gluten catalyzed by Alcalase were glutenconcentration of3%(w/v),the viscosity that the hydrolysis of gluten catalyzed by Alcalase.with the increase of the hydrolysis time.both foam and foam stability increased with theincrease of enzymatic hydrolysis time, and both emulsifying and emulsion stability increasedwith the increase of enzymatic hydrolysis time.