尼罗罗非鱼鱼皮胶原蛋白中游离基清除肽的制备及其抗氧化活性

摘要

Gelatin extracted from tilapia (Oreochromis niloticus) skin was hydrolyzed with serial digestions in the order of Bromelain and Alcalase.The antioxidative activity in vitro of tilapia skin gelatin hydrolysates (TGH) was researched.The results showed TGH had strong superoxide/hydroxyl radical scavenging ability and the IC50 value was 3.13 mg·mL-1 and 3.58 mg·mL-1,respectively.The TGH was fractionated into five major types of TGH-Ⅰ(＞10 ku),TGH-Ⅱ(10-5 ku),TGH-Ⅲ(5-3 ku),TGH-Ⅳ(3-1 ku),and TGH-Ⅴ(below 1 ku) using an ultrafiltration (UF) membrane bioreactor system based on the molecular weight cut-offs.The fraction of TGH-Ⅴ,exhibited the highest superoxide scavenging activity,was further purified using consecutive chromatographic methods including gel filtration,ion-exchange chromatography,and reverse-phase high performance liquid chromatography.The purified peptide had a strong scavenging ability on superoxide and the IC50 value was 4.6 μg·mL-1.And the molecular weight of the purified peptide was between 311.3-932.8 u determined by MS.%采用菠萝蛋白酶和Alcalase酶依次对尼罗罗非鱼皮胶原进行复合酶解.研究了该酶解产物的体外抗氧化活性.实验表明,该酶解产物具有较强的超氧阴离子/羟基自由基清除活性和还原能力.采用不同截留分子量的超滤膜将该酶解物分离成5个组分,即TGH-Ⅰ(＞10 ku),TGH-Ⅱ(10～5 ku),TGH-Ⅲ(5～3 ku),TGH-Ⅳ(3～1 ku)和TGH-Ⅴ(10 ku).其中TGH-Ⅴ组分显示出最强的超氧阴离子自由基清除活性,因此采用凝胶过滤、离子交换和反向高压液相色谱技术对该组分进一步分离纯化.纯化得到的肽具有很强的超氧阴离子自由基清除活性,其IC50值为4.6 μg·mL-1.通过质谱分析可知,该肽的分子量位于311.3～932.8 u之间.