Changes in physicochemical characteristics and metabolites in the fermentation of goji juice by Lactiplantibacillus plantarum

Abstract

We used untargeted metabolomics based on LC-MS/MS to investigate the changes in metabolites following L. plantarum fermentation of goji juice. Additionally, we assessed the changes in physicochemical characteristics, free amino acid and organic acid levels. Total phenols, total flavonoids, and antioxidant activity improved after L. plantarum fermentation. We screened 31 primary metabolites using multivariate statistical analysis in primary metabolic network. L. plantarum consumed sugars and amino acids in goji juice. Lactic acid, gamma amino butyric acid, and phenylacetaldehyde accumulated after fermentation. Amino acids with bitter taste were converted into acetal derivatives, which contributed to umami and kokumi taste. Indole-3-lactic acid was the top one characteristic secondary metabolite after fermentation. There were 6.25 and 4.19 mg/L indole-3-lactic acid accumulated after fermentation, whereas it was not detected in goji juice. The accumulation of tyrosol was strain-dependent. Fermentation by L. plantarum altered the metabolite profile, improves taste, and increased the levels of several biologically active substances. These results are essential for understanding the bioprocessing of goji juice by L. plantarum.