Study on the Extracting Technology for Antioxidant Oligopeptides from Donkey Meat by Two-Step Enzymatic Hydrolysis

Donkey (Equus asinus L.) is an important source of medicinal material in China. Both the hide and meat of donkeys have a variety of physiological activities such as the hide is sufficiently employed for making Ejiao (Colla Corii Asini). The physiological efficacy value of donkey meat is not maximized due to lack of advanced extracting methodologies. In this study, an innovative extracting technology was established for the extraction of antioxidant oligopeptides from donkey meat by two-step enzymatic hydrolysis. The influensce of enzymolysis on the degree of hydrolysis (Dh) and protein recovery (PR) were evaluated, and the chemical composition, antioxidant activity, and molecular weight distribution of oligopeptides in hydrolysates were studied. The optimum enzymatic hydrolysis conditions were identified at 5.96 ph, 0.7% enzyme-substrate ratio, 55°C temperature and 3 h time. Under these optimum conditions, Dh of 25.4%, PR of 95% was obtained. Moreover, hydrolysates were rich in oligopeptides, especially di-and tri-peptides and demonstrated good antioxidant activities. These results introduce a new methodology with the provision of fundamental data for the production of antioxidant oligopeptides from donkey meat. Keywords: Donkey meat, Papain enzyme, Antioxidant properties, Extracting technology.