The Antioxidative Activity Of Enzymatic Hydrolysates Of Corn Gluten Meal And Its Application

Corn gluten meal is a byproduct of the com wet-milling process and contains more than 60%protein. The major drawback of using corn gluten meal in food industry is that it is very insoluble inwater and the contents of Lys and Trp is low. Currently, the main use of corn gluten meal is as ananimal feed or it is discharged as wastes, which is a great mass of waste and pollution forenvironment. Enzymatic hydrolysis has been used to increase the solubility of corn gluten meal andthe hydrolysates have a lot of physiological activity, which profit the development of corn glutenmeal and increase the utilization of corn resource.The main objective here was to study the optimum hydrolysis condition of preparing comprotein hydrolysates with high antioxidative activity, separation and purification of corn proteinhydrolysates, the composition of amino acid and the inhibitory effects on lipid oxidation in raw andcooked pork patties.The optimum hydrolysis conditions of preparing hydrolysates with high antioxidative activityby Alcalase alkaline protease hydrolyzing corn gluten meal was determined by adopting the singlefactor experiments, with the index of inhibiting oxidative capacity in liposome-oxidizing systemand reducing power of the hydrolysates: Temperature 50℃, pH value 9.0, substrate concentration10%, ratio of enzyme to substrate 1.0% and time of hydrolysis 5h.The relationship between the degree of hydrolysis (DH) and antioxidative activity wasevaluated by determining DH of the hydrolysates with different hydrolysis time. The antioxidativeactivity of the hydrolysates did not become strong with DH increasing. When the DH was 26.49%,the antioxidant activity of the hydrolysates was strongest.The corn protein hydrolysates at a 1.0%,1.5%,2.0% concentration level were added to rawpork patties, During the storage period, a value, TBARS, pH value, metMb(%) were measuredand sensory evaluation was performed on raw pork patties. The results showed that the treatmentsadded hydrolysates had significant inhibitory effects on lipid oxidation and kept the red color ofpatties in 7 days, when compared with controls. The inhibitory effect enhanced as the adding levelof the hydrolysates increased. Nonhydrolyzed corn gluten meal (2.0% adding level) and BHA(0.02% adding level)were added to raw patties in order to make a comparison, the conclusion wasthat the treatments with hydrolysates had higher inhibitory effects on lipid oxidation thannonhydrolyzed corn gluten meal, but they were inferior to BHA. The same results were got by sensory evaluation.The hydrolysates at a 1.0%,1.5%,2.0% concentration level were added to cooked pork patties,during the storage period, a value, TBARS, pH value, were measured and sensory evaluation wasperformed on cooked pork patties. The results showed that the treatments added hydrolysates hadsignificant inhibitory effects on lipid oxidation and the same results were got by sensory evaluation.