Influence of Different Hydrolysis Processes by Trypsin on the Physicochemical, Antioxidant, and Functional Properties of Collagen Hydrolysates fromSphyrna lewini, Dasyatis akjei, andRaja porosa

ABSTRACTAcid soluble collagen hydrolysates from the cartilages of Sphyrna lewini, Dasyatis akjei, and Raja porosa on different hydrolysis conditions by trypsin were prepared and named as S, D, and R, respectively. The hydrolysates (S1, D1, and R1) obtained from hydrolysis in pH 2.5, 3 h, 37°C presented wonderful foaming and emulsifying capacities, caused by their high average molecular weights (AMWs), high degree of Pro and Lys hydroxylation, and imino acid contents (17.1, 15.3, and 14.1%). At the concentration of 0.1% (w/v), the foaming capacities of S1, D1, and R1 were 104.75 ± 2.57, 63.87 ± 2.73, and 76.87 ± 2.02%; and the emulsifying activity indexes of them were 116.07 ± 1.89, 91.04 ± 1.79, and 123.85 ± 2.14 m2/g, respectively. Conversely, hydrolysates (S2, D2, and R2) obtained from hydrolysis in pH 7.8, 3 min, 37°C exhibited strong scavenging activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical (EC50 0.568, 0.680, and 1.634 mg/mL), hydroxyl radical (EC50 0.253, 0.376, and 0.438 mg/mL), and moderate reducing power (0.0465–0.4702 at the concentration of 5 mg/mL), due to their low AMWs. The results indicated that S1, D1, and R1 could be used as emulsifiers and foaming agents, and S2, D2, and R2 could be used as natural antioxidants in food systems.KEYWORDS: Sphyrna lewiniDasyatis akjeiRaja porosacollagen hydrolysate of cartilageantioxidant activityphysicochemical and functional properties AcknowledgmentsThe authors are greatly indebted to Professor Sheng-Long Zhao at the School of Marine Science and Technology, Zhejiang Ocean University, for his valuable help in identifying the fish material.FundingThis work was financed by the National Natural Science Foundation of China (No. 31001109), Zhejiang Province Science Foundation (No. Y2110636), and the Special Program for the Science and Technology Plan of Zhejiang Province (2011C02003).Additional informationFundingThis work was financed by the National Natural Science Foundation of China (No. 31001109), Zhejiang Province Science Foundation (No. Y2110636), and the Special Program for the Science and Technology Plan of Zhejiang Province (2011C02003).