Dynamic interactions between compositional changes and color evolution in Lactobacillus fermented Lotus rhizome...

Lotus rhizome juice (LRJ) is prone to undergoing color alterations, which adversely impact its commercial appeal during the processing stages. When inoculated with Lactobacillus PE331 after sterilization, LRJ exhibits a suppression of browning intensification during the thermostatic fermentation process. However, the specific mechanisms and compositional shifts underlying these color-modifying effects remain unexplored. The results revealed that the L^⁎ value of fermented lotus rhizome juice (FLRJ) increased significantly throughout the fermentation process, while the a^⁎, b^⁎, and A₄₂₀ values showed an opposite trend. There was a substantial increase in the antioxidant potential of FLRJ, which was mainly characterized by an increase in total phenol content, DPPH radical scavenging ability (DSA), and total antioxidant capacity (TAC), as well as the maintenance of ascorbic acid content. An apparent reduction in the content of six reducing sugars was also monitored especially glucose and lactose. Organic acid content was on the rise, particularly lactic acid. The correlation analysis (CA) and principal components analysis (PCA) manifested that the depletion of reducing sugars, the production of organic acids, and the enhancement of antioxidant capacity were the three main pathways to inhibit the browning of FLRJ, while glucose, lactic acid, oxalic acid, and citric acid were the main contributing components.