以富硒核桃为原料经提油后得到富硒核桃粕，以血管紧张素转化酶（ACE）抑制作为评估标志，经单因素影响试验和响应面优化富硒核桃粕蛋白ACE抑制肽的制备工艺，并将酶解物进行超滤分离、氨基酸组成分析和硒含量测定。结果显示，富硒核桃粕蛋白ACE抑制肽的最佳酶解温度为35 ℃，酶解时间为2.52 h，pH值7.5、底物浓度5.39%、加酶量0.33%，在此试验条件下进行的验证试验ACE抑制率为79.13%，与理论值为78.84%较相符。最优酶解物经3 ku超滤膜分离，发现<3 ku超滤组分在1 mg/mL浓度下ACE抑制活性高达77.78%。同时，富硒核桃粕蛋白ACE抑制肽酶解物中疏水性氨基酸占27.19%，硒元素在酶解物和<3 ku超滤组分中的含量分别为0.82 mg/kg和1.35 mg/kg。该研究为食物源性补硒产品和辅助降血压健康食品的研究与开发提供了理论依据。

Selenium-rich walnut meal was obtained after extracting oil from selenium-rich walnuts, and the inhibition of angiotensin-converting enzyme (ACE) was used as an evaluation marker. The preparation process of ACE-inhibiting peptides in selenium-rich walnut meal was optimized through single-factor experiments and response surface methodology, and the hydrolysate was subjected to ultrafiltration separation, amino acid composition analysis, and selenium quantification. The following conditions were optimal for the preparation process of ACE-inhibiting peptides in selenium-rich walnut meal: enzymatic hydrolysis temperature of 35 ℃, enzymatic hydrolysis time of 2.52 h, pH of 7.5, substrate concentration of 5.39%, and enzyme addition amount of 0.33%. The ACE inhibition rate in the verification test performed under these experimental conditions was 79.13%, which was close to the theoretical value of 78.84%. The optimal hydrolysate was separated using a 3 ku ultrafiltration membrane, and the ACE inhibition activity of the <3 ku ultrafiltration fraction was 77.78% at the concentration of 1 mg/mL. Hydrophobic amino acids accounted for 27.19% of the hydrolysate of ACE-inhibiting peptides in selenium-rich walnut meal, and the selenium content of the hydrolysate and <3 ku ultrafiltration fraction was 0.82 and 1.35 mg/kg, respectively. These findings provide a theoretical basis for research and development on food-derived selenium supplementation products and auxiliary blood pressure-lowering functional foods.

农业农村部富硒产品开发与质量控制重点实验室开放课题（Se-2020B04）