条斑紫菜多糖对α-淀粉酶的抑制效果

Inhibitory effect of polysaccharide from Porphyra yezoensis on α-amylase

目的分析条斑紫菜多糖对α-淀粉酶的抑制效果。方法从条斑紫菜中提取多糖α-淀粉酶抑制剂(α-amylase inhibitor,α-AI),分析其在不同浓度(2.5~30 mg/m L)下,经热(30~90℃,20 min)、酸(p H 2.0~7.0,室温,30 min)、碱(p H 7.0~10.0,室温,30 min)、蛋白酶(分别为100 U/g的风味蛋白酶、中性蛋白酶和碱性蛋白酶,50℃,2 h)以及模拟胃肠道环境(胃处理:p H 2.0,100 U/g胃蛋白酶;肠道处理:p H 8.2,100 U/g胰蛋白酶)处理后对α-AI活性的影响,探讨α-AI的稳定性及其对淀粉酶的抑制效果。结果条斑紫菜多糖α-AI在多糖浓度为2.5~30 mg/m L之间对α-淀粉酶的抑制呈剂量依赖关系,浓度为30 mg/m L具有较高的抑制率。经不同条件处理,α-AI活性无显著变化(P>0.05),仍具有良好的淀粉酶抑制活性,且其活性在胃液和肠液中稳定,可较好地发挥生理作用。结论条斑紫菜多糖α-AI在控制血糖稳定方面具有较强的应用价值,可作为2型糖尿病患者潜在的功能性食品。

Objective To analyze the inhibitory effect of polysaccharide from Porphyra yezoensis onα-amylase.Methods Polysaccharideα-amylase inhibitor(α-AI)was extracted from P.yezoensis and analyzed for activity change at various concentrations(2.5~30 mg/m L)as well as after treatment by heat(30~90℃,20 min),acid(p H 2.0~7.0,room temperature,30 min),base(p H 7.0~10.0,room temperature,30 min)and protease(100 U/g flavourzyme,neutral protease and alkaline protease respectively,50℃,2 h)and in mimic gastrointestinal environment(100 U/g pepsin for gastric treatment,p H 8.2,100 U/g trypsin for enteric treatment),and evaluated for stability and inhibitory effect on amylase.Results Theα-AI at a concentration of 2.5~30 mg/m L showed a dose-dependent inhibitory effect onα-amylase.The activity ofα-AI showed no significant change after treatment under various conditions(P>0.05)and was stable in gastric and enteric fluids.Conclusion Theα-AI from P.yezoensis may be used for control of blood glucose,which may be developed as a potentially functional food for patients with type 2 diabetes.