Effects of microbial fermentation from Jiangshui source on the multiscale structure, physicochemical properties, and...

Microbial fermentation, as a green and efficient starch modification technology, shows great potential in optimizing the functional properties of starch. In this study, Lactiplantibacillus plantarum L1 and Pichia kudriavzevii K1 were isolated from traditional Chinese fermented food Jiangshui and employed to ferment quinoa starch. Both strains induced common modifications including surface erosion, significantly increased solubility, reduced swelling power and gel strength, and markedly improved starch digestibility by increasing the content of rapidly digestible starch (RDS) and decreasing the content of resistant starch (RS). Specifically, the RDS content increased from 64.92 % to 69.62 %, while the RS content decreased from 17.81 % to 12.73 % under the same condition. Notably, the two strains regulated the starch properties through distinct mechanisms. L. plantarum L1 fermentation was more effective in reducing starch granular size and branching degree, leading to a substantial enhancement in oil-holding capacity (increased by 38.57 %). In contrast, P. kudriavzevii K1 fermentation significantly enhanced the water-holding capacity (increased by 33.80 %) and solubility (increased by 21.91 %), which was associated with its pronounced effect on improving the short-range molecular order. This research can lay a foundation for the development and application of microbial resources for starch fermentation modification.