Abstract: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.
