Digestibility of resistant starch containing preparations using two in vitro models.
BACKGROUND
Resistant starch (RS) is known for potential health benefits in the human colon. To investigate these positive effects it is important to be able to predict the amount, and the structure of starch reaching the large intestine.


OBJECTIVE
The aim of this study was to compare two different in vitro models simulating the digestibility of two RS containing preparations.


METHODS
The substrates, high amylose maize (HAM) containing RS type 2, and retrograded long chain tapioca maltodextrins (RTmd) containing RS type 3 were in vitro digested using a batch and a dynamic model, respectively. Both preparations were characterized before and after digestion by using X-Ray and DSC, and by measuring their total starch, RS and protein contents.


RESULTS
Using both digestion models, 60-61 g/100 g of RTmd turned out to be indigestible, which is very well in accordance with 59 g/100 g found in vivo after feeding RTmd to ileostomy patients. In contrast, dynamic and batch in vitro digestion experiments using HAM as a substrate led to 58 g/100 g and 66 g/100 g RS recovery. The degradability of HAM is more affected by differences in experimental parameters compared to RTmd. The main variations between the two in vitro digestion methods are the enzyme preparations used, incubation times and mechanical stress exerted on the substrate. However, for both preparations dynamically digested fractions led to lower amounts of analytically RS and a lower crystallinity.


CONCLUSIONS
The two in vitro digestion methods used attacked the starch molecules differently, which influenced starch digestibility of HAM but not of RTmd.
Fässler
Caroline
C
Institute of Food Science and Nutrition, ETH Zurich, LFO D28 Schmelzbergstr. 9, 8092, Zürich, Switzerland.
Arrigoni
Eva
E
Venema
Koen
K
Hafner
Valeria
V
Brouns
Fred
F
Amadò
Renato
R
D000688:Amylose / Q000008:administration & dosage / Q000378:metabolism*; D004043:Dietary Fiber / Q000008:administration & dosage / Q000378:metabolism*; D004063:Digestion; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D011134:Polysaccharides / Q000008:administration & dosage / Q000378:metabolism*; D013213:Starch / Q000378:metabolism*; D013379:Substrate Specificity; D013997:Time Factors
D004043:Dietary Fiber; D011134:Polysaccharides; C008315:maltodextrin; D013213:Starch; D000688:Amylose