牛肉酶解工艺优化及其氨基酸组成分析

采用牛肉屠宰加工中废弃碎肉渣制成的冻干肉粉为原材料，以蛋白酶解度为评价指标，探究碱性蛋白酶与风味蛋白酶组成的复合酶最佳酶解条件。在单因素试验基础上，采用5因素3水平正交试验对酶解条件进行优化，并测定最终酶解液中游离氨基酸的种类与含量。结果表明：最佳酶解工艺为酶添加量4%、碱性蛋白酶与风味蛋白酶质量比1∶5、酶解温度50 ℃、pH 8.5、肉粉蛋白添加量5%、酶解时间8 h，在该条件下，牛肉蛋白水解度为（45.7±0.6）%；酶解液中氨基酸分为3 个含量区段，其中脯氨酸含量最高，为（256.20±18.65） mg/100 mL，甘氨酸含量最低，为（4.46±0.56） mg/100 mL。

Optimization of Enzymatic Hydrolysis of Beef and Analysis of Amino Acid Composition of Hydrolysate

Beef trimmings as a waste from beef slaughter and processing were ground and freeze-dried before being hydrolyzed with combinations of alkaline protease and flavourzyme. Hydrolysis conditions were optimized using one-factor-at-a-time method combined with a five-factor, three-level orthogonal array design based on degree of hydrolysis (DH). The amino acid composition of the hydrolysate prepared using the optimized conditions was determined. The optimum hydrolysis conditions were found to be total enzyme amount of 4%, alkaline protease/flavourzyme ratio of 1:5 (m/m), temperature of 50 ℃, pH of 8.5, substrate concentration of 5%, and time of 8 h. Experiments conducted under these conditions gave a DH of (45.7 ± 0.6)%. In the resulting hydrolysate, the contents of proline and glycine were the highest and lowest, (256.20 ± 18.65) and (4.46 ± 0.56) mg/100 mL, respectively.