复合酶提取法对浒苔(Enteromorpha sp.)膳食纤维吸附能力的影响

针对丰富的浒苔资源还未得到有效利用的现状，以浒苔为原料，采用复合酶提取法制备浒苔膳食纤维。浒苔在55℃、pH=7.7的条件下，由不同比例的蛋白酶和纤维素酶(5:1、10:1、15:1、20:1和25:1)配制的复合酶进行酶解，提取膳食纤维，测定不同提取条件得到的浒苔膳食纤维在模拟体内的环境下(pH=2.0和pH=7.0)吸附葡萄糖、胆固醇和亚硝酸盐的能力。结果显示，随着复合酶中蛋白酶比例的升高，膳食纤维对葡萄糖和胆固醇的吸附能力先增强后减弱。在蛋白酶∶纤维素酶的比例为10:1时，膳食纤维对葡萄糖的最大吸附值为20.03 mg/g；在蛋白酶∶纤维素酶比例为15:1时，膳食纤维对胆固醇的最大吸附值为21.93 mg/g。而浒苔膳食纤维吸附亚硝酸的能力则随着复合酶中蛋白酶比例的升高而逐渐增强，在蛋白酶∶纤维素酶比例为25:1时，浒苔膳食纤维对亚硝酸盐达到最大吸附值29.25 µmol/g。在人工肠液中(pH=7.0)，膳食纤维对胆固醇的吸附能力较强；在人工胃液中(pH=2.0)，膳食纤维对亚硝酸盐的吸附能力较强；膳食纤维对葡萄糖的吸附能力在人工肠、胃液中无显著差异(P>0.05)。推测膳食纤维对亚硝酸盐的吸附主要发生在胃部，对胆固醇的吸附主要发生在肠部，而膳食纤维对葡萄糖的吸附在胃部和肠部同时进行，是一个持续的吸附过程。

Effects of Complex Enzymes Extraction on Adsorption Capabilities of Dietary Fiber from Entenmorpha sp.

Entenmorpha sp. is widely distributed along the coast of China, particularly in the eastern regions, but it has not been utilized fully. To investigate the adsorption of glucose, cholesterol and nitrite to the dietary fiber extracted from Entenmorpha sp. by the method of complex enzymes (protease and cellulase), different ratios of protease to cellulase (5:1, 10:1, 15:1, 20:1, and 25:1) were used to extract dietary fiber from Entenmorpha sp. The results showed that the ratio of protease to cellulase in the complex enzymes had obvious effects on the adsorption capabilities of the dietary fiber. With the increased protease in the complex enzymes, the adsorption of glucose and cholesterol to the dietary fiber increased and then decreased. The dietary fiber using the 10:1 ratio of protease and cellulase had highest adsorption of glucose (20.03 mg/g). The dietary fiber using the 15:1 ratio of protease to cellulose had the highest adsorption of cholesterol (21.93 mg/g). With the increased protease, the adsorption of nitrite to the dietary fiber increased. The dietary fiber had highest adsorption of nitrite (29.25 µmol/g) at the 25:1 ratio of protease to cellulose. Furthermore, the adsorption capabilities of the diary fiber in the simulated gastric fluid at pH 2.0 and the intestinal fluid at pH 7.0 were investigated. The adsorption of cholesterol to the dietary fiber was higher in the simulated intestinal fluid than that in the simulated gastric fluid, while nitrite was the opposite. The adsorption of glucose to the dietary fiber had no significant difference in the simulated intestinal and the simulated gastric fluids. These results indicated that the adsorption of nitrite to dietary fiber happened in the stomach and cholesterol happened in the intestinal, and that the adsorption of glucose to the dietary fiber happened both in the stomach and in the intestinal.