Enzymatic Hydrolysis of Coconut Protein and Antioxidant Activity of the Hydrolysates

Coconut was crushed and defatted,giving coconut powder.Coconut protein was obtained by alkaline extraction and acid precipitation from coconut powder.Then coconut protein was hydrolyzed by four proteases(Alcalase,Neutrase,bromelin,Papain),among which Alcalase showed to be the optimal in terms of degree of hydrolysis and DPPH.scavenging rate of hydrolysates.By single factor and multi-index orthogonal design,hydrolysis conditions were optimized using degree of hydrolysis and DPPH.scavenging rate as the evaluating indexes.Hydrolysis temperature and substrate concentration showed the highest influence on DPPH.scavenging activity.The optimal conditions were substrate concentration 2%(m/V),enzyme concentration 14000 U/g,pH 10.5,temperature 50 ℃ and hydrolyzing time 7 h.Under these conditions,the protein content of hydrolysates,the scavenging rate on DPPH.and the degree of hydrolysis were 15.8 mg/mL,89.07% and 29.16%,respectively.The antioxidant activity of coconut hydrolysates closed to that of the same concentration of glutathione,being 3.33 times higher than that of the same concentration of Vitamin C.