Mechanism of Regulation of Intestinal Environment and Biological Functions by Food Components

难消化淀粉成分存在于淀粉类食物中。这可能有助于改善肠道功能，如膳食纤维。以高直链淀粉为原料制备抗性淀粉，并与果胶、甘露聚糖等膳食纤维进行比较研究。以纤维素粉作为对照，给5周龄Wistar系大鼠喂食含有4%和8%膳食纤维的每种膳食纤维来源的膳食3周。RS与水溶性膳食纤维（PE和KM）一样具有可发酵性，虽然RS被归类为不溶性膳食纤维，但它有助于降低肠道环境，产生短链脂肪酸。在8%RS组中，观察到血浆胆固醇和甘油三酯水平显著降低，同时肝脏脂质降低。RS和KM组胆汁酸排泄量较低，PE组较高，RS、KM组粪胆固醇较高，PE组粪胆固醇较低。RS和8%KM组粪便中性甾体含量较低，PE组较高，RS的作用不像PE那样来源于抑制吸收，而是通过改善肠道环境，抑制初级物质向次级物质的生物转化，从而影响宿主动物。

Indigestible starch component is present in starchy food. This may function to improve intestinal functions like dietary fiber. In this experiment, resistant starch (RS) was prepared from high-amylose starch and investigated its functions in comparison to dietary fiber such as pectin (PE) and konjac mannan (KM). Five-weeks-old rats of the Wistar strain were fed diets containing each DF source at levels of 4 and 8% as DF in diets for 3 weeks as cellulose powder as the control. RS was revealed to be fermentable like water soluble DFs (PE and KM) and contribute to the lowering of intestinal environment with production of short-chain fatty acids though it was classified as insoluble DF.In 8%RS group significant decrease in the levels of cholesterol and triglyceride in plasma was observed concomitant with decreases in liver lipids. Excretion of bile acids tended to be low in RS and KM,but was tended to be high in PE.Fecal cholestrol tended to be high in RS,KM and especially in PE.However fecal coprostanol was significantly lower in all test groups. Fecal neutral steroids tended to be low in 8%RS and 8%KM,and high in PE.The function of RS was not originated from inhibition of absorption like PE,but seemed to affect the host animal by suppressing biotransformation of primary substances to secondary substances through improvement of intestinal environment.