Yu Wenwen, Zou Wei, Dhital Sushil, Wu Peng, Gidley Michael J, Fox Glen P, Gilbert Robert G
Joint International Research Laboratory of Agriculture and Agri-Product Safety, College of Agriculture, Yangzhou University, Yangzhou 225009, Jiangsu Province, China; The University of Queensland, Center for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, Brisbane, QLD 4072, Australia.
The University of Queensland, Center for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, Brisbane, QLD 4072, Australia.
Food Chem. 2018 Feb 15;241:493-501. doi: 10.1016/j.foodchem.2017.09.021. Epub 2017 Sep 7.
The conversion of barley starch to sugars is a complex enzymic process. Most previous work concerned the biotechnical aspect of in situ barley enzymes. However, the interactions among the macromolecular substrates and their effects on enzymic catalysis has been little examined. Here, we explore the mechanisms whereby interactions of protein and starch in barley flour affect the kinetics of enzymatic hydrolysis of starch in an in vitro system, using digestion rate data and structural analysis by confocal microscopy. The degradation kinetics of both uncooked barley flour and of purified starches are found to be two-step sequential processes. Barley proteins, especially the water-soluble component, are found to retard the digestion of starch degraded by α-amylase: the enzyme binds with water-insoluble protein and with starch granules, leading to reduced starch hydrolysis. These findings are of potential industrial value in both the brewing and food industries.
大麦淀粉向糖的转化是一个复杂的酶促过程。此前的大多数研究都关注大麦原位酶的生物技术方面。然而，大分子底物之间的相互作用及其对酶催化的影响却很少被研究。在这里，我们利用消化速率数据和共聚焦显微镜进行结构分析，探索大麦粉中蛋白质和淀粉的相互作用影响体外系统中淀粉酶促水解动力学的机制。发现未煮熟的大麦粉和纯化淀粉的降解动力学都是两步连续过程。发现大麦蛋白，尤其是水溶性成分，会阻碍α-淀粉酶降解淀粉的消化：该酶与水不溶性蛋白和淀粉颗粒结合，导致淀粉水解减少。这些发现对酿造和食品工业都具有潜在的工业价值。
