Effect of particle size on kinetics of starch digestion in milled barley and sorghum grains by porcine alpha-amylase
Effect of particle size on kinetics of starch digestion in milled barley and sorghum grains by porcine alpha-amylase
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DOI：
10.1016/j.jcs.2009.05.001
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发表时间：
2009-09-01
影响因子：
3.8
通讯作者：
Gidley, Michael J.
中科院分区：
文献类型：
--
作者：
Al-Rabadi, Ghaid J. S.;Gilbert, Robert G.;Gidley, Michael J.
考察了粉碎粒度对淀粉酶消化动力学的影响。两种类型的谷物(大麦和高粱)被磨碎，结果是用筛子按大小分开，大小从类似的0.1毫米到类似的3毫米不等。用胰α-淀粉酶、淀粉糖苷酶和蛋白水解酶进行体外酶消化，测定24 h以上的分步消化率，葡萄糖产生率符合简单的一级动力学方程。在不同的筛分尺寸下，大麦的消化率始终高于高粱。消化速率系数随颗粒大小的增加而减小，且可用反平方关系很好地拟合。这与淀粉在这些体系中的消化是由酶在颗粒碎片中的扩散控制的假设是一致的。α-淀粉酶在水中的表观扩散系数分别为0.76(高粱)和1.7x10(-7)cm(2)S(-1)，9(高粱)和4(大麦)。(C)2009爱思唯尔有限公司。保留所有权利。
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.