七种大宗淡水鱼酶解物抗氧化活性比较及其肽组成鉴定

Comparison of antioxidant ability of enzymatic hydrolysates from sevenconventional freshwater fish and identification of peptide composition

淡水鱼产量大且富含蛋白质,是抗氧化肽的优质来源。该研究以7种大宗淡水鱼为原料制备抗氧化肽,比较了鱼肉的基本成分,通过超滤技术分离出不同分子质量的肽组分,通过不同体外模型评价各组分的抗氧化活性,并通过液相色谱串联质谱技术鉴定肽组成。结果表明,7种淡水鱼的水分、灰分、粗蛋白和粗脂肪含量差异显著(P<0.05),其酶解液超滤组分的分子质量主要分布在2 139~2 902 Da和408~1 156 Da,占比超过90%。分子质量<3 kDa的肽组分的抗氧化活性高于粗肽和高分子质量多肽,草鱼、青鱼和鳙鱼<3 kDa的肽组分分别具有最强的ABTS阳离子自由基清除能力[IC_(50)=(196.73±16.27)μg/mL]、还原能力[IC_(50)=(6.47±0.41) mg/mL]和亚铁离子螯合能力[IC_(50)=(114.00±3.41)μg/mL],是抗氧化肽的最佳来源。采用质谱技术从<3 kDa组分中鉴定出510条肽段,其中共有的肽段有3条,分别为KDPIDPPWAPGKP、DPIDPPWAPGKP和VLDRPGPPEGPL。该研究可促进淡水鱼的高值化利用,并为淡水鱼中抗氧化肽的开发提供指导。

Freshwater fish is a good source of antioxidant peptides due to its abundant protein and great output.In this study,seven kinds of conventional freshwater fish were used to prepare antioxidant peptides,and the fundamental constituents of raw materials were determined.The peptide fractions with different molecular weights were separated by ultrafiltration technology,the antioxidant activities of each fraction were evaluated by different models in vitro,and the peptide composition was identified by liquid chromatography-tandem mass spectrometry.Results showed that the contents of water,ash,crude protein,and crude fat in seven kinds of freshwater fish were significantly different(P<0.05),and the molecular weight(M_(w))of ultrafiltration fractions from enzymatic hydrolysate were mainly distributed in 2139-2902 Da and 408-1156 Da,which accounted for over 90%.The antioxidant activity of peptides with M_(w)<3 kDa were stronger than that of crude peptides and peptides with M_(w)>3 kDa.The<3 kDa peptide fractions from grass carp,black carp,and bighead carp showed the strongest ABTS cationic radical scavenging ability[(196.73±16.27)μg/mL],reducing ability[(6.47±0.41)mg/mL],and ferrous ion chelating ability[(114.00±3.41)μg/mL],respectively,which were the best sources of antioxidant peptides.A total of 510 peptide fragments were identified from<3 kDa peptide fractions by mass spectrometry,including KDPIDPWAPGKP,DPIDPPWAPGKP,and VLDRPGPPEGPL.This study could promote the high-value utilization of conventional freshwater fish and guide the development of antioxidant peptides from freshwater fish.