Structural Orders of Wheat Starch Do Not Determine the In Vitro Enzymatic Digestibility.
In this study, we elucidated the underlying mechanisms that are responsible for the rate-limiting step for wheat starch digestion. Wheat starch samples with a degree of gelatinization (DG) ranging from 0 to 100% were prepared. As DG increased, the ordered structures of the starch were disrupted increasingly. In contrast, almost all of the increase in the rate and extent of in vitro enzymatic digestion coincided with a DG of only 6% and a minor loss of structural order. As DG increased beyond 6%, digestibility of the starch increased only slightly. We propose that the access and binding of enzymes to starch is greatly increased with only a small DG, which is followed by the simultaneous hydrolysis of crystalline and amorphous areas in gelatinized starch. In vitro enzymatic digestibility of starch was determined predominantly by enzyme binding to starch rather than the ordered structures of starch.
Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology , Tianjin 300457, People's Republic of China.
Shujun
http://orcid.org/0000-0003-4501-8047
S
Wang
Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology , Tianjin 300457, People's Republic of China.
Shaokang
S
Wang
Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology , Tianjin 300457, People's Republic of China.
Lu
L
Liu
Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology , Tianjin 300457, People's Republic of China.|Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University , Beijing 100048, People's Republic of China.
Shuo
http://orcid.org/0000-0003-0910-6146
S
Wang
School of Life and Environmental Sciences, The University of Sydney , Camperdown, New South Wales 2006, Australia.
Les
L
Copeland
D004063:Digestion; D005780:Gelatin / Q000737:chemistry; D006868:Hydrolysis; D013213:Starch / Q000737:chemistry* / Q000378:metabolism; D014908:Triticum / Q000737:chemistry* / Q000378:metabolism
D005780:Gelatin; D013213:Starch
degree of gelatinization; enzyme binding; kinetic constant; multiscale structure; starch digestion