岩藻低聚糖的酶法制备及活性分析

利用岩藻聚糖硫酸酯酶对岩藻聚糖硫酸酯进行降解，获得岩藻低聚糖。利用均匀设计和正交设计方法，设计122组试验，通过Matlab软件建立3层BP网络模型模拟酶解过程，运用遗传算法对上述网络进行寻优。并利用D-半乳糖致衰老小鼠模型，对岩藻低聚糖和岩藻聚糖硫酸酯的抗氧化活性进行对比研究。结果表明，在加酶量0～24U/mg、酶解温度20～40℃、酶解时间0～4h的酶解条件下，产物分子质量会发生显著性变化，选取上述范围作为寻优范围。遗传算法寻优结果表明，当加酶量20.7U/mg、酶解温度26℃、酶解时间2.3h时，能够获得最大抗氧化活性的岩藻低聚糖，该产物的1,1-二苯基-2-三硝基苯肼自由基清除率达到85.1%，分子质量为18.2kDa。体内动物实验结果表明，岩藻低聚糖较岩藻聚糖硫酸酯在羟自由基清除率、丙二醛活力及减少过氧化氢酶含量等抗氧化指标方面都有显著提高（P＜0.05）。本实验为工业化制备高抗氧化活性岩藻聚糖硫酸酯水解产物提供了一定实验支撑。

Enzymatic Preparation and Activity of Fucosylated Oligosaccharides

Fucoidanase was used to degrade fucoidan to obtain fucosylated oligosaccharides. A total of 122 experiments were designed and implemented using uniform design and orthogonal array design. A three-layer BP network model was built to simulate the hydrolysis process, and it was optimized by genetic algorithm using Matlab software. A mouse model of D-galactose-induced aging was used to test the antioxidant activities of fucosylated oligosaccharides and fucoidan. The results showed that the molecular weight of hydrolysates was changed significantly during 4 h hydrolysis at 20–40 ℃ with 0–24 U/mg of fucoidanase. On the basis of this finding, the optimization was carried out and the result showed that an enzyme dosage of 20.7 U/mg, a temperature of 26 ℃ and a hydrolysis time of 2.3 h were found to be the optimal conditions to obtain a hydrolysate with the highest antioxidant activity. The hydrolysate scavenged 85.1% 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical with a molecular weight of 18.2 kDa. The results of animal experiments showed that the antioxidant activity of fucosylated oligosaccharides were significantly higher than that of fucoidan in terms of hydroxyl free radical scavenging activity, catalase (CAT) activity and malonaldehyde (MDA) content (P < 0.05). This paper can provide experimental support for the industrial preparation of fucoidan hydrolyzate with high antioxidant activity.