牡蛎酶解液的抗氧化活性

检测了牡蛎(Crassotera gigas)木瓜蛋白酶和中性蛋白酶酶解液的抗氧化活性。由Sephadex G-15葡聚糖凝胶柱层析分析牡蛎酶解液,得到具抗氧化活性组分的分子量分布。分子量为1191 D和826 D左右的木瓜蛋白酶酶解活性肽组分的自由羟基清除活性最强,当其质量浓度分别为0.184 mg/mL和0.673 mg/mL时,体外自由羟基清除活性分别为53.6%和66.5%;分子量分别为1074 D和735 D左右的中性蛋白酶酶解活性肽的自由羟基清除活性最强,当其质量浓度分别为0.166 mg/mL和0.830 mg/mL时,体外自由羟基清除活性分别57.6%和70.5%。HPLC分析结果表明,木瓜蛋白酶与中性蛋白酶酶解的活性肽组分分别由几种抗氧化肽组成。抗氧化活性最强的木瓜蛋白酶与中性蛋白酶酶解的肽组分在质量浓度为2.5 mg/mL时,活性分别可达83.6%和80.8%。用牡蛎原浆与各酶解液灌胃昆明小白鼠。研究结果表明,用木瓜蛋白酶与中性蛋白酶酶解原液及经超滤纯化的酶解液对小白鼠实施灌胃,其肝脏组织的SOD活力都显著提高(P<0.05);灌胃经超滤纯化的木瓜蛋白酶和中性蛋白酶酶解液,小白鼠肝脏组织GSH-PX活力、GSH含量显著提高(P<0.05),MDA含量显著降低(P<0.05)。

Antioxidative activity of oyster hydrolysates

Oyster was hydrolyzed by papain and neutral proteases and antioxidative activity of oyster hydrolysate was studied.Scavenging hydroxyl radical activities of peptide fractions analyzed by Sephadex G-15 showed considerable variations.The peptide molecular weights with highest scavenging hydroxyl radical activities hydrolyzed by papain were about 1 191 D and 826 D and their scavenging activities of hydroxyl radical were 53.6% and 66.6% respectively when the peptide concentrations were 0.184 mg/mL and 0.673 mg/mL,and the molecular weights of the peptides hydrolyzed by neutral protease were about 1 074 D and 735 D respectively and their scavenging activities were determined as 57.6% and 70.5% respectively when the peptide concentrations were 0.166 mg/mL and 0.830 mg/mL.Further isolating and purifying results made by HPLC indicated that when the concentration of the peptides with highest scavenging activities made separately by papain and neutral protease was 2.5 mg/mL,their scavenging activities were determined as 83.6%and 80.8% respectively.Study on white mice fed by papain and neutral protease hydrolysates after membrane separation(UF) showed that activities of GSH-PX,SOD and GSH in liver tissue mice were improved considerably compared with that of the white mice fed by crude oyster meat(P<0.05).In contrast,enhancement of MDA content was significantly inhibited by supplement of the same hydrolysates(P<0.05).The results of the white mice fed by papain and neutral protease hydrolysates without membrane separation only improved the activities of SOD significantly(P<0.05).