琼胶寡糖的生物酶解制备工艺研究

Optimization of the preparation for the agar oligosaccharides by enzymatic hydrolysis

以龙须菜为原料,以琼胶得率为指标,采用正交实验研究了液料比、水提温度、水提时间对琼胶得率的影响,得到最佳水提琼胶工艺条件;进一步以水解度为指标,采用响应曲面法研究了pH、酶解温度、底物浓度对琼胶水解度的影响,得到最优酶解工艺。结果表明,琼胶的最佳水提条件为:液料比281(v/w),水提温度120℃,水提时间90 min,在此条件下,琼胶得率为32.8%。酶解时间2h,加酶量20 U/mL条件下的最优酶解工艺为:pH6.4,酶解温度54℃,底物浓度0.6%(w/v),此时水解度为89.75%。经薄层层析分析,酶解产物为偶数新琼寡糖(DP2、4、6、8),其中主要产物为新琼四糖,为功能性琼胶寡糖的开发应用打下基础。

The agar was obtained from Gracilaria lemaneiJormis by water extraction. The optimal solvent- to- solid ratio, temperature and extraction time in the extration process were analysed by orthogonal test according to the yield of agar.Then the optimal pH value,hydrolysis temperature and substrate concentration in agar＇ s enzymatic process were analysed by response surface method according to the degree of hydrolysis of agar.Result showed that the conditions containing solvent-to-solid ratio of 28：1 （ v/w）, temperature of 120 ℃ and extraction time of 90 minutes was found to be optimal for extraction of agar and the yield of agar was 32.8% .The condition cantaining pH value of 6.4, temperature of 54 ℃ and substrate concentration of 0.6% （w/v）was found to be optimal for degrading agar and the degree of hydrolysis of agar was 89.75%. The products of enzymatic hydrolysis were determined as neoagarooligo saccharides with DPs of 2, 4, 6, and 8 by TLC, in which Neoagarotetraose was the major product,lay the foundation for the development and application of functional oligosaccharides agar.