以英红九号红茶渣为原料，通过碱提酸沉提取茶叶蛋白，以黄嘌呤氧化酶抑制率为指标，采用单因素和响应面实验优化酶解制备降尿酸肽，对其氨基酸组成进行分析，并对最优酶解物进行超滤分离和活性评价。结果表明，在底物浓度2%（m/V）、加酶量0.3%（m/V）、温度39 ℃、pH值7.5和酶解时间3.4 h条件下，得到的降尿酸肽的黄嘌呤氧化酶抑制率为85.42%。氨基酸分析表明，降尿酸肽中必需氨基酸含量丰富（38.49%），高比例的疏水性氨基酸（48.00%）和碱性氨基酸（13.67%）对黄嘌呤氧化酶抑制活性有重要作用。酶解物经过超滤分离后，与原酶解物的活性（IC50 0.72 mg/mL）比较，<3 ku组分的黄嘌呤氧化酶抑制活性显著提升（IC50 0.41 mg/mL）。该研究可为茶叶蛋白的高值化利用提供参考，为茶叶源新型降尿酸健康食品的开发提供了理论依据。

Taking Yinghong NO.9 black tea dregs as the raw material, the tea protein was extracted by alkali extraction and acid precipitation. Taking the inhibition rate of xanthine oxidase as the index, uric acid-lowering peptides were prepared via enzymolysis after optimization through single factor experiments and response surface test. The amino acid composition was analyzed, and the optimal enzymatic hydrolysate were subjected to separation via ultrafiltration and activity evaluation. The results showed that under the conditions of 2% substrate concentration, 0.3% enzyme amount, temperature 39 ℃, pH 7.5 and enzymolysis time 3.4 h, the obtained uric acid-lowering peptides exhibited a xanthine oxidase inhibitory rate of 85.42%. Amino acid analysis showed that the uric acid-lowering peptides were rich in essential amino acids (38.49%), and had high proportions of hydrophobic amino acids (48.00%) and basic amino acids (13.67%), which were important for its xanthine oxidase inhibitory activity After the separation of the enzymatic hydrolysate via ultrafiltration, the xanthine oxidase inhibitory activity (IC50: 0.41 mg/mL) of the fraction with a molecular weight <3 ku inreased significantly compared to the activity of the initial enzymatic hydrolysate (IC50: 0.72 mg/mL).This study provides a reference for the high-value utilization of tea protein, and a theoretical basis for the development of a novel tea-derived uric acid-lowering health food.

广东省茶树资源创新利用重点实验室开放课题（2020KF01）