小麦麸皮粗多糖的基本结构特征、流变特性及其对体外消化酶抑制初探

Physicochemical properties and digestive enzymes in vitro inhibitory activities of polysaccharides from wheat bran

小麦麸皮是小麦加工过程中的主要副产物,具有很高的营养价值与多种生物活性,其中非淀粉多糖含量较高,是主要活性成分之一。本试验采用碱提醇沉法制备小麦麸皮阿拉伯木聚糖(Wheat bran arabinoxylan,WBAX),采用高效液相色谱、离子色谱、红外光谱、SEM、流变等技术与方法,系统研究了WBAX的基本结构特征、流变特性以及对消化酶抑制的效果。结果表明,WBAX以中性糖为主(83.4%),同时含有少量蛋白质(8.6%)和糖醛酸(0.9%),主要由阿拉伯糖(30.3%)和木糖(37.8%)组成;阿拉伯糖与木糖的摩尔比(A/X)为0.8,表明WBAX支化程度较高。WBAX表观黏度存在剪切稀化行为,且随温度增加而降低。WBAX的微观形貌主要为片状、球状和丝状。此外,与α-葡萄糖苷酶抑制实验相比,WBAX对α-淀粉酶抑制率相对较高,且随着多糖浓度增加,对α-淀粉酶抑制率有一定上升趋势。综上所述,从小麦麸皮提取获得WBAX主要为阿拉伯木聚糖,具有一定的抑制α-淀粉酶活性作用,相关结果可为WBAX的开发与应用提供理论依据。

Wheat bran is a by-product of wheat processing,which has high nutritional value and various biological activities,among which non-starch polysaccharide is one of the main active components.Wheat bran arabinoxylan(WBAX)was prepared by alkaline extraction and ethanol precipitation.Physicochemical properties,rheological properties and digestive enzymes were systematically studied by high performance liquid chromatography,ion chromatography,infrared spectroscopy,SEM and rheology.The result showed that main component of WBAX were neutral sugar(83.4%),small amounts of protein(8.6%)and uronic acid(0.9%).Monosaccharide composition of WBAX were mainly consisted of arabinose(30.3%)and xylose(37.8%).Molar ratio of arabinose to xylose(A/X)was 0.8,which represented a degree of branching in arabinoxylan.Rheological techniques indicated that apparent viscosity of WBAX exhibited a shear thinning flow behavior and decreased with increasing temperature.Flaky,globose and filamentous shapes were visualized by SEM observation.Moreover,compared with theα-glucosidase inhibition experiment,the inhibition rate ofα-amylase by WBAX was relatively higher,and the inhibition rate ofα-amylase increased with the increase of polysaccharide concentration.In conclusion,WBAX extracted from wheat bran is mainly arabinoxylan,which has a certain inhibitory effect onα-amylase activity.The results of this study can provide theoretical basis for the research and application of wheat bran arabinoxylan.