[关键词]
[摘要]
谷物β-葡聚糖是β-D-吡喃型葡萄糖基单元通过(1→4)-β-键重复连接并被单一(1→3)-β-D-键分离而形成的一种线性同聚多糖,同时也是谷物水溶性膳食纤维的主要成分,主要存在于大麦、燕麦、青稞、小麦和黑麦中。谷物可溶性β-葡聚糖的生理效应与其独特的结构具有密切关系,本文注重于谷物β-葡聚糖的分子结构特征与其在胃肠道中的生理活性的关系,总结了谷物可溶性β-葡聚糖在降低胆固醇、餐后血糖指数与胰岛素水平上等生理活性的研究,探讨了谷物β-葡聚糖对肠道菌群与免疫作用的新机制。对几种β-葡聚糖生理活性机理的研究进行了描述:增加小肠黏度水平因此延缓胃排空、消化和分子吸收,包括葡萄糖、膳食胆固醇和胆汁酸;于小肠中与胆汁酸相结合降低胆汁酸重吸收,进而促进利用胆固醇的胆汁酸合成;降低餐后血糖指数与胰岛素水平改善胰岛素敏感性;于盲肠、结肠中发酵改善肠道健康。
[Key word]
[Abstract]
Cereal β-glucans are a type of linear homopolysaccharides formed by the linkage of β-D- glucopyranosyl units via (1→4)-β-linkage and separated by single (1→3)-β-linkages. They are the main component of water-soluble dietary fibers from cereals and are mainly found in barley, oat, hull-less barley, wheat, and rye. The physiological activity of soluble β-glucan from cereal is closely related to its unique structure of (1→3)(1→4)-β-D-glucan. This paper focused on the relationship between the characteristics of the molecular structure of cereal β-glucans and their physiological activity in the gastrointestinal tract. The physiological activities of cereal soluble β-glucans in reducing cholesterol, postprandial glycemic index, and insulin levels are summarized and new mechanisms underlying the effect of β-glucans on the intestinal flora and immune function are discussed. Studies on several mechanisms underlying the physiological activities of β-glucan are described. The viscosity level in the small intestine was increased, delaying the gastric emptying, digestion, and absorption of molecules, including glucose, dietary cholesterol, and bile acids. β-glucans bound with bile acid in the intestine to decrease the bile acid reabsorption, thus promoting the synthesis of bile acids from cholesterol. β-glucans improved insulin sensitivity by reducing postprandial glycemic index and insulin level and underwent colonic fermentation to improve intestinal health.
[中图分类号]
[基金项目]
中央高校基本科研业务费专项资助项目(2013ZM0065);广东省天然产物绿色加工与产品安全重点实验室开放基金资助项目(201304);广东省高等学校科技创新重点项目(2012CXZD0009);国家自然科学基金项目(31201330);广州市科技攻关项目(201300000202);华南理工大学百步梯攀登计划项目(DC30715040)