Sour liquid fermentation is a traditional and unique method used in China to produce starch that has favorable sensory evaluation,especially a pleasant mouthfeel.However,the complexity of the natural microbial flora u...Sour liquid fermentation is a traditional and unique method used in China to produce starch that has favorable sensory evaluation,especially a pleasant mouthfeel.However,the complexity of the natural microbial flora used in the method often caused severe fluctuations in production efficiency and product quality.Hence,it is important to explore the performance and impact of each starch-flocculating bacteria on starch structure.In this study,five previously isolated starch-flocculating bacterial strains were used to ferment sweet potato starch individually.Through analyzing fermentation parameters,Leuconostoc citreum SJ-48 was identified as the strain with the highest starch flocculation ability.A more dispersed particle size distribution of starch after fermentation was observed,possibly due to the clumping of starch granules by the bacteria.It was found that the amylose content of fermented starch increased by 27.57%-42.28%,and the relative crystallinity of starch increased significantly after fermentation.Finally,the starch-binding proteins of the bacterial cell were characterized using LC-ESI-MS/MS,and it was revealed that the strong starch flocculation ability of L.citreum SJ-48 was linked to the glycoside hydrolase family 70 on its surface.This study demonstrated that the discrepancies in the flocculation ability of the different bacterial strains and subsequent changes in the fermented starch properties were mainly influenced by the different proteins on their surfaces.展开更多
基金supported by the Natural Science Foundation of Sichuan Province 2023NSFSC0181the 2115 Talent Development Program of China Agricultural University.
文摘Sour liquid fermentation is a traditional and unique method used in China to produce starch that has favorable sensory evaluation,especially a pleasant mouthfeel.However,the complexity of the natural microbial flora used in the method often caused severe fluctuations in production efficiency and product quality.Hence,it is important to explore the performance and impact of each starch-flocculating bacteria on starch structure.In this study,five previously isolated starch-flocculating bacterial strains were used to ferment sweet potato starch individually.Through analyzing fermentation parameters,Leuconostoc citreum SJ-48 was identified as the strain with the highest starch flocculation ability.A more dispersed particle size distribution of starch after fermentation was observed,possibly due to the clumping of starch granules by the bacteria.It was found that the amylose content of fermented starch increased by 27.57%-42.28%,and the relative crystallinity of starch increased significantly after fermentation.Finally,the starch-binding proteins of the bacterial cell were characterized using LC-ESI-MS/MS,and it was revealed that the strong starch flocculation ability of L.citreum SJ-48 was linked to the glycoside hydrolase family 70 on its surface.This study demonstrated that the discrepancies in the flocculation ability of the different bacterial strains and subsequent changes in the fermented starch properties were mainly influenced by the different proteins on their surfaces.
