罗非鱼皮明胶酶解物及其模拟消化产物的抗氧化活性

以罗非鱼皮为原料提取罗非鱼皮明胶,选用风味蛋白酶和胰蛋白酶制备罗非鱼皮明胶酶解物,采用ABTS自由基、DPPH自由基、羟基自由基及亚油酸过氧化体系,初步评价罗非鱼皮明胶酶解物的抗氧化活性,再通过模拟体外胃肠道消化实验,结合分子质量分布测定,进一步考察罗非鱼皮明胶酶解物的抗氧化活性。结果显示,在酶解过程中,风味蛋白酶及胰蛋白酶酶解的水解度逐渐升高,在3 h时达到最高,分别达到5.8%和25.36%。在酶解60 min时其TCA可溶性肽得率最高,风味蛋白酶、胰蛋白酶酶解物分别达56.82%和54.44%。通过比较半抑制浓度（IC₅0）,确定了酶解60 min时风味蛋白酶酶解物的清除DPPH自由基及抑制亚油酸过氧化能力较胰蛋白酶酶解物强。模拟体外胃肠道消化后,酶解物羟基自由基清除活性均显著提高（p<0.05）,亚油酸脂质过氧化活性明显降低,消化前后样品分子量分布范围均主要集中于3000⁵000 Da,消化后风味蛋白酶及胰蛋白酶酶解物3000⁵000 Da组分的含量分别提高了45%及13%。以上研究结果表明,罗非鱼皮明胶酶解后制备的明胶水解物具有一定的抗氧化能力,具有潜在的开发价值。 

Antioxidant activity of tilapia (Oreochromis niloticus) skin gelatin hydrolysates and its simulated digestive products

In this paper, gelatin was extracted from tilapia skin and then separately hydrolysed by trypsin and flavourzyme.Antioxidant efficacy of respective hydrolysates were evaluated using 2, 2'-azino-bis ( 3-ethylbenzthiazoline-6-sulphonic acid) ( ABTS) radical, 1, 1-diphenyl-2-picrylhydrazyl ( DPPH) radical, hydroxyl radical scavenging and lipid peroxidation in linoleic acid inhibitory activities. The gastrointestinal digestion in vitro and molecular weight distribution of hydrolysates further evaluated the antioxidant activities. The results showed that the hydrolysis degree of flavourzyme and trypsin hydrolysates gradually increased during enzymatic hydrolysis, the highest DH values of 5.8% and 25.36% were observed in trypsin and flavourzyme hydrolysates after 3 h of hydrolysis. TCA soluble peptide content of flavourzyme and trypsin hydrolysates were higher after hydrolyzed for 60 min than other hydrolysis times, which respectively reached 56.82% and 54.44%. The gelatin hydralysates by flavourzyme and trypsin for 60 min of hydrolysis showed stronger antioxidant abilities of ABTS, DPPH, hydroxyl radical scavenging activities and anti-linoleic acid peroxidation capacity.Flavourzyme hydralysates had more potent activities on scavenging DPPH radical and inhibiting lipid peroxidation compared to trypsin hydrolysate respectively. After in vitro gastrointestinal digestion, both hydrolysates showed significant higher hydroxyl radical scavenging and lower oxidation of linoleic acid inhibitory activity ( p < 0.05) .The molecular weight distribution of the hydrolysates was mainly concentrated in 3000⁵000 Da before and after digestion in vitro. The content ( 3000 ~ 5000 Da) increased by 45% and 13% for flavourzyme and trypsin hydrolysates after digestion, respectively. These results suggested that gelatin hydrolysates, from tilapia skin, could serve as a potential source of functional food ingredients for health promotion.