体内外实验测定淀粉的消化吸收特性

目的　采用体内外实验测定方法比较不同性质的淀粉 ,即可消化淀粉 (DS)和抗性淀粉 (RS)的消化吸收特性。方法　根据Englyst方法采用体外消化实验方法测定了 4种淀粉样品中DS、RS含量 ,再采用十二指肠灌注法直接将DS、RS注入到大鼠十二指肠 ,观察 4h内血糖变化 ,另采用代谢实验方法观察RS对碳水化合物和氮表观吸收率的影响 ,以及对消化酶分泌的影响。结果　体外实验表明 ,4种淀粉样品中以普通市售玉米淀粉DS含量最高 ,而马铃薯淀粉中 76 %为不消化的RS。动物实验表明 ,DS在十二指肠灌注后1 2 0min内血糖达到最大峰值 ;RS吸收相对缓慢 ,但总表观吸收率仍可达 96 %以上。另外RS可促进粪氮排出 ,降低氮表观吸收率 ,并可改变胃液和胃蛋白酶分泌。结论　利用体内外实验方法证明RS吸收缓慢但相对完全 ,部分佐证了Englyst以消化时间 1 2 0min作为界定DS和RS的方法

Digestive and absorptive characteristic of starches determined in vitro and in vivo

Objective To compare the different digestive and absorptive characteristic of digestible starch(DS) and resistant starch(RS), using both in vitro and in vitro methods.Methods Firstly, DS and RS content in four starchy samples were determined in vitro according to Englyst's method. Secondly, DS and RS digestion and absorption were evaluated by determination of four hour blood glucose level, after direct injection of DS and RS solution into rats' duodenum. And in another animal test, the effect of RS on apparatus absorption rate of carbohydrate and nitrogen and secretion of gastric acid and pepsin was observed.Results In vitro, it was showed that general cornstarch was rich of DS, while 76% of photato starch was RS. In vitro, it was tested that after injection of DS into duodenum, most of DS could be absorbed in 120 min with high peak value of plasma glucose. While, RS needed more time to complete its absorption, and its apparatus absorption was up to 96%. It was also showed that RS could increase fecal nitrogen excretion,decrease nitrogen apparatus absorption rate and change gastric acid and pepsin excretion.Conclusion By both in vitro and in vitro methods, RS is identified to be absorbed slowly but completely. The results partly support Englyst's method, which regards 120min as the time point to separate DS with RS in vitro.