Journal
JOURNAL OF CEREAL SCIENCE
Volume 50, Issue 2, Pages 198-204Publisher
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
DOI: 10.1016/j.jcs.2009.05.001
Keywords
Starch digestion; alpha-Amylase; Grain particle size; Diffusion
Categories
Funding
- Co-operative Research Centre
- Internationally Competitive Pork Industry and the Australian Research Council [DP0985694]
Ask authors/readers for more resources
The influence of milled grain particle size on the kinetics of enzymatic starch digestion was examined. Two types of cereals (barley and sorghum) were ground, and the resulting grounds separated by size using sieving, with sizes ranging from similar to 0.1 to similar to 3 mm. In vitro enzymatic digestion was performed, using pancreatic alpha-amylase, amyloglucosidase and protease, to determine fractional-digestion rates over 24 h. The resulting glucose production rate data were well fitted by simple first-order kinetics. For each sieve screen size, the digestion rate of barley was always higher than that of sorghum. The rate coefficients for digestion showed a decrease with increasing size, and could be well fitted by an inverse square relationship. This is consistent with the supposition that starch digestion in these systems is controlled by diffusion of enzyme through the grain fragment. Apparent diffusion coefficients of alpha-amylase obtained by fitting the size dependence were 0.76 (sorghum) and 1.7 (barley) x 10(-7) cm(2) s(-1), 9 (sorghum) and 4 (barley) times slower than predicted for a molecule of the size of alpha-amylase in water. (C) 2009 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available