Ou S, Kwok K, Li Y, Fu L
Research Center of Food Science and Technology, Jinan University, Guangzhou 510632, People's Republic of China.
J Agric Food Chem. 2001 Feb;49(2):1026-9. doi: 10.1021/jf000574n.
There have been many reports concerning the role of dietary fiber in lowering postprandial serum glucose, and the main mechanism was regarded as the viscosity of different dietary fibers in hampering diffusion of glucose and postponing absorption and digestion of carbohydrates. In this paper, two kinds of water-insoluble dietary fibers, water-insoluble dietary fiber of wheat bran and enzyme-resistant starch of maize amylose, and four kinds of water-soluble dietary fibers, water-soluble dietary fiber of wheat bran, carboxymethyl cellulose, guar gum, and xanthan gum, were used to investigate their postprandial serum glucose lowering mechanism in vitro. The results showed that these dietary fibers lowered postprandial serum glucose levels at least by three mechanisms. First, dietary fibers increase the viscosity of small intestine juice and hinder diffusion of glucose; second, they bind glucose and decrease the concentration of available glucose in the small intestine; and, third, they retard alpha-amylase action through capsuling starch and the enzyme and might directly inhibit the enzyme. All of these decreased the absorption rate of glucose and the concentration of postprandial serum glucose.
关于膳食纤维在降低餐后血清葡萄糖方面的作用已有许多报道，其主要机制被认为是不同膳食纤维的黏性阻碍了葡萄糖的扩散，并延缓了碳水化合物的吸收和消化。本文选用了两种水不溶性膳食纤维，即麦麸水不溶性膳食纤维和玉米直链淀粉的抗酶解淀粉，以及四种水溶性膳食纤维，即麦麸水溶性膳食纤维、羧甲基纤维素、瓜尔豆胶和黄原胶，来研究它们在体外降低餐后血清葡萄糖的机制。结果表明，这些膳食纤维至少通过三种机制降低餐后血清葡萄糖水平。第一，膳食纤维增加小肠液的黏度并阻碍葡萄糖的扩散；第二，它们结合葡萄糖并降低小肠中可利用葡萄糖的浓度；第三，它们通过包裹淀粉和酶来延缓α-淀粉酶的作用，并且可能直接抑制该酶。所有这些都降低了葡萄糖的吸收率和餐后血清葡萄糖的浓度。
