Effect of germination temperature on hierarchical structures of starch from brown rice and their relation to pasting properties

The study aimed to obtain the information on the effect of germination temperature on hierarchical structures (granular structure, crystal structure, short-range ordered structure and helical structures) of starch from brown rice and their relation to pasting properties. The results showed that brown rice had gradually elevated germination ability and alpha-amylase activity as the sprouting temperature rose. And the enhanced enzyme activities during germination promoted the erosion of starch granules, the decrease of relative crystallinity and short-range ordered degree, and the unwinding of double helix structure. In addition, the mathematical correlation and structure-pasting relationship were constructed in this work. These structural disorganizations of germinated rice starch resulted in reduced swelling degree and water-holding capacity, inducing the lower paste viscosity (e.g., peak and final viscosity), breakdown and setback value. Thus, it is concluded that germination can efficiently regulate the pasting properties of starch, which provide a crucial basis for the development and utilization of germinated brown rice products. (C) 2019 Published by Elsevier B.V.