罗非鱼排二段酶解工艺优化及其对酶解液风味物质的影响

Optimization of two-step enzymatic hydrolysis of Tilapia frame and its effect on the flavor compounds of hydrolysates

为获知二段(或分步)酶解工艺对罗非鱼排水解液中风味物质的影响,通过响应面分析法研究了风味蛋白酶二段酶解罗非鱼排的最佳工艺,并分析比较一段酶解液以及二段酶解液中的游离氨基酸种类及含量,同时采用顶空—固相微萃取(HS-SPME)结合气质联用(GC-MS)技术对酶解液挥发性风味物质组成进行分析研究。结果显示:在温度为55℃,pH为7.0,加酶量为1315 U/g时,水解4 h,水解度可达47.22%,显著高于一段酶解液(33.70%);二段酶解液的游离氨基酸总量及必需氨基酸含量分别提高224.39 mg/100 mL和114.15 mg/100mL,呈鲜味及甜味的氨基酸所占比例提高3.26%;二段酶解液挥发性风味成分中醛类物质的相对含量提高了9.0%,愈创木酚、1-辛烯-3-醇等特征风味物质相对含量有所降低。研究表明,二段酶解工艺不仅可以提高罗非鱼排水解度,还可改善酶解液的风味成分。

In order to learn the effect of two-step enzymatic hydrolysis on the flavor compounds of Tilapia frame hydroly- sates, the optimal conditions of the two-step enzymatic hydrolysis were obtained by using Response Surface Analysis, and then the free amino acids and the volatile flavor components in one-step and two-step hydrolysates were analyzed. Resuhs indicated that the optimal conditions for two-step hydrolysis by flavourzyme were as follows ： pH value was 7.0, time was 4 h, temperature was 55 ~C, enzyme dosage was 1315 U/g. The degree of hydrolysis could reach 47. 22%, 13.52% higher than that of one-step enzymatic hydrolysis under the optimum values. Total free amino acids and essential amino acids content combined with the proportion of delicious amino acid （ sweet or umami ） in the two-step hydrolysates increased by 224. 39 mg/100 mL, 114. 15 mg/100 mL and 3.26% , respectively. Meanwhile, the relative ratio of aldehydes in the volatile flavor components from the two-step hydrolysates increased 9. 0%. However, the contents of some characteristic flavor compounds such as guaiaeol and 1-octene-3-alcohol were significantly reduced. Therefore, two-step enzymatic hydrolysis methodology could not only improve the degree of hydrolysis, but also improve the flavor compounds of hydrolysates.