虎斑乌贼生殖腺多肽的制备工艺优化及其体外抗氧化活性

Optimized preparation technology and in vitro antioxidant activities of cuttlefish( Sepia pharaonis) gonad peptides

为了实现乌贼副产物的高值化利用,以虎斑乌贼生殖腺作为枯草芽孢杆菌的唯一发酵基质,以发酵液的蛋白酶活力和非蛋白氮含量为评价指标,通过单因素及正交试验确定最佳的发酵工艺。同时,对发酵产物的体外抗氧化活性及其氨基酸组成进行了研究。结果表明,最佳的发酵条件为:底物质量浓度为30mg/mL,培养基的初始pH值6.0,发酵温度34℃,发酵时间60h。在此条件下,发酵液的蛋白酶活力及非蛋白氮含量分别为(66.66±0.64)U/mL和(1.10±0.02)mg/mL。所得的发酵产物具有良好的体外抗氧化活性,其羟自由基清除能力、超氧阴离子自由基清除能力及亚铁离子螯合能力的IC50值分别为19.40、8.90和1.75mg/mL。氨基酸组成分析表明,发酵产物中赖氨酸含量最高,其抗氧化氨基酸和疏水性氨基酸的含量分别占总氨基酸含量的63.3%和39.1%,具有很好的抗氧化潜力,可作为天然抗氧化剂或功能性食品添加剂应用于食品加工中。

In order to realize high value utilization of cuttlefish by-products,the gonad of Sepia pharaonis was used as a sole substrate to ferment Bacillus subtilis . Using protease activity and non-protein nitrogen content of the fermentation broth as evaluation indexes,the fermentation process was optimized. Besides,the in vitro antioxidant activities and amino acid composition of the fermentation products were studied. The results showed that the optimal fermentation condition was as follows: 30 mg/mL substrate,fermented at 34 ℃ for 60 h,with an initial pH of 6.0. Under this condition,the protease activity and non-protein nitrogen content of the fermentation broth were (66.66±0.64) U/mL and (1.10±0.02) mg/mL,respectively. Moreover,the fermentation products exhibited good antioxidant activities in vitro,as their IC 50 values of scavenging hydroxyl radicals,superoxide anion radicals and chelating ferrous ions were 19.40 mg/mL,8.90 mg/mL,and 1.75 mg/mL,respectively. Furthermore,the amino acid composition analysis showed that lysine content was the highest in the fermentation product,and antioxidant and hydrophobic amino acids accounted for 63.3% and 39.1% of total amino acids respectively. Therefore,gonad peptides of cuttlefish can be used as natural antioxidants or functional food additives during food processing.