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
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摘要: 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。Abstract: The agar was obtained from Gracilaria lemaneiformis 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 p H 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 p H value of 6.4,temperature of 54 ℃ and substrate concentration of0.6%( 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.