title: Antioxidative peptides derived from enzyme hydrolysis of bone collagen after microwave assisted acid pre-treatment and nitrogen protection.
abstract: This study focused on the preparation method of antioxidant peptides by enzymatic hydrolysis of bone collagen after microwave assisted acid pre-treatment and nitrogen protection. Phosphoric acid showed the highest ability of hydrolysis among the four other acids tested (hydrochloric acid, sulfuric acid and/or citric acid). The highest degree of hydrolysis (DH) was 9.5% using 4 mol/L phosphoric acid with a ratio of 1:6 under a microwave intensity of 510 W for 240 s. Neutral proteinase gave higher DH among the four protease tested (Acid protease, neutral protease, Alcalase and papain), with an optimum condition of: (1) ratio of enzyme and substrate, 4760 U/g; (2) concentration of substrate, 4%; (3) reaction temperature, 55 °C and (4) pH 7.0. At 4 h, DH increased significantly (P < 0.01) under nitrogen protection compared with normal microwave assisted acid pre-treatment hydrolysis conditions. The antioxidant ability of the hydrolysate increased and reached its maximum value at 3 h; however DH decreased dramatically after 3 h. Microwave assisted acid pre-treatment and nitrogen protection could be a quick preparatory method for hydrolyzing bone collagen.
authors.affiliation: School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; E-Mails: yunjianl@163.com (Y.-J.L.); wang_jieyun@yahoo.com.cn (J.-Y.W.); liyaxin1220@163.com (Y.-X.L.).
authors.forename: Yun-Jian
authors.initials: YJ
authors.lastname: Lin
authors.forename: Guo-Wei
authors.initials: GW
authors.lastname: Le
authors.forename: Jie-Yun
authors.initials: JY
authors.lastname: Wang
authors.forename: Ya-Xin
authors.initials: YX
authors.lastname: Li
authors.forename: Yong-Hui
authors.initials: YH
authors.lastname: Shi
authors.forename: Jin
authors.initials: J
authors.lastname: Sun
mesh_terms: D000143:Acids / Q000737:chemistry; D000818:Animals; D000975:Antioxidants / Q000737:chemistry* / Q000302:isolation & purification; D001842:Bone and Bones / Q000737:chemistry; D003094:Collagen / Q000737:chemistry*; D006868:Hydrolysis; D008872:Microwaves; D009584:Nitrogen / Q000737:chemistry; D010447:Peptide Hydrolases / Q000737:chemistry; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification; D013552:Swine
chemical_list: D000143:Acids; D000975:Antioxidants; D010455:Peptides; D003094:Collagen; D010447:Peptide Hydrolases; D009584:Nitrogen