Effects of co‐fermentation of Lactobacillus plantarum and inulin on beany flavor and physicochemical quality of soy yogurt in a multiple lactic acid bacteria fermentation system

Abstract Background and Objectives Soybean yogurt is a nutritious, healthy, and environmentally friendly plant‐based beverage. However, the product's beany flavor and coarse texture have reduced consumer acceptance. The aim of this work was to investigate the effect of cofermentation of Lactobacillus plantarum and inulin on beany flavor and physicochemical quality of soy yogurt in a multilactic acid bacteria fermentation system. Findings The cofermentation of L. plantarum and inulin could effectively reduce the beany flavor compounds. With the increase of fermentation time, the lactic acid bacteria number gradually increased, the pH value decreased significantly ( p < .05) from about 6.8 to 4.5, and the titratable acidity eventually reached about 50°T. When adding 0.04% (wt/vol) L. plantarum , as the rise of inulin from 3% to 9%, the color of soy yogurts showed golden yellow, the values of L *, a *, b *, and ∆ E changed nonsignificantly ( p > .05), and the viscosity, hardness, gumminess, cohesiveness, and adhesiveness significantly ( p < .05) increased. When inulin was incorporated at 6% (wt/vol), the soy yogurt had the most outstanding water‐holding capacity (72.46%), dense and uniform protein gel microstructure, suitable adhesiveness (−37.55 g s), and optimal overall acceptance. Conclusions Soy yogurt prepared from soymilk by adding 6% (wt/vol) inulin and inoculating 3% (wt/vol) lactic acid bacteria mixture ( Lactobacillus bulgaricus:Streptococcus thermophilus = 1:4, wt/wt) and 0.04% (wt/vol) L. plantarum had the optimal overall acceptance. Significance and Novelty The results would provide a new reference method for the industrial production of low‐beany flavor and high‐quality soy yogurt.