[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 potato 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.


CONCLUSIONS
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.
Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing.
Zhu
Z
Wang
Guodong
G
Wang
Mei
M
He
Yuexin
Y
Yang
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D004063:Digestion; D007408:Intestinal Absorption; D010434:Pepsin A / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013213:Starch / Q000032:analysis / Q000493:pharmacokinetics*
D001786:Blood Glucose; D013213:Starch; D010434:Pepsin A