玉足海参低聚肽的制备及其体外抗氧化活性分析

Preparation of Oligopeptides from Holothuria leucospilota and Analysis of Their Antioxidant Activity in Vitro

摘要:

【目的】分析玉足海参（Holothuria leucospilota）体壁的营养成分，优化玉足海参低聚肽制备工艺并评价其体外抗氧化活性。【方法】 采用国家标准中的方法测定玉足海参体壁的基本营养成分及氨基酸组成；以多肽得率和相对分子质量分布为指标，通过蛋白酶筛选、单因素试验结合正交试验优化玉足海参低聚肽提取工艺；采用自由基清除率和亚铁离子螯合能力评估其体外抗氧化活性。【结果】玉足海参体壁干基中粗蛋白质质量分数最高，为（64.59±9.45）%。最佳酶解工艺为：选择碱性蛋白酶，酶解温度70 ℃、酶解pH 9.5、酶解时间3 h、加酶量3 000 U/g、料液比1 g∶11 mL。在此条件下，多肽得率达75.75%，酶解产物中相对分子质量<2 000的组分占比超98.00%。ABTS^＋自由基清除率、羟自由基清除率、超氧阴离子自由基清除率和亚铁离子螯合能力的IC₅₀分别为0.93、0.51、8.97、0.40 mg/mL。【结论】玉足海参体壁富含优质蛋白质，该研究优化的酶解工艺合理可行、多肽得率较高，制得的玉足海参低聚肽具有良好的抗氧化活性，可作为功能食品开发的潜在原料。

Abstract:

[Objective] This study aims to analyze the nutritional components of Holothuria leucospilota body wall, optimize the preparation process of Holothuria leucospilota oligopeptides, and evaluate their antioxidant activity in vitro. [Method] The basic nutritional components and amino acid composition were determined via national standard methods. Through protease screening and single-factor experiments combined with orthogonal design, the conditions for enzymatic hydrolysis were optimized, with the polypeptide yield and relative molecular weight distribution serving as evaluation indicators. Antioxidant activity in vitro of the obtained oligopeptides was assessed based on the free radical scavenging rates and Fe²⁺-chelating ability. [Result] The body wall of Holothuria leucospilota (on a dry basis) exhibited the highest crude protein mass fraction of (64.59±9.45)%. The conditions for enzymatic hydrolysis were optimized as follows: hydrolysis with 3 000 U/g alkaline protease and a solid-to-liquid ratio of 1 g∶11 mL at 70 ℃ and pH 9.5 for 3 h. Under these conditions, the polypeptide yield reached 75.75%, with over 98.00% of components having the relative molecular mass below 2 000. The IC₅₀ of the obtained oligopeptides for scavenging ABTS⁺ free radicals, scavenging hydroxyl free radicals, scavenging superoxide anion free radicals, and chelating Fe²⁺ were 0.93, 0.51, 8.97, and 0.40 mg/mL, respectively. [Conclusion] The body wall of Holothuria leucospilota is rich in high-quality protein. The established enzymatic hydrolysis process is efficient and feasible, with a high polypeptide yield. The obtained oligopeptides of Holothuria leucospilota demonstrate strong antioxidant activity, serving as a potential raw material for the development of functional foods.