Supplementary data.docx

The selection of appropriate starter cultures is a crucial factor in determining the quality of fermented soymilk products. This study evaluated the effects of a combined starter culture of <i>Enterococcus faecium </i>CGMCC 29309 and <i>Lactiplantibacillus plantarum</i> CGMCC 29306 on the microbiological, physicochemical, textural and rheological characteristics of fermented soymilk. The results indicated that the mixed-strain fermentation significantly increased the concentrations of free isoflavones, free amino acids, free fatty acids, and aroma compound acetaldehyde, 2,3-butanedione and acetoin, and significantly reduced the level of beany compound hexanal. The fermentation also greatly improved the textural and rheological characteristics of fermented soymilk. The <i>Enterococcus faecium</i> strain played a leading role in the mixed-strain fermentation, whereas the <i>Lactiplantibacillus plantarum</i> strain was found to be necessary due to its greater ability to break down conjugated isoflavones. This study provides a theoretical basis for using the combined lactic acid bacteria starter to prepare premium fermented soymilk products.