Characterizations of lactic acid bacteria derived from pickles and the effects of fermentation on phenolic compounds in peony flowers

This study aims to characterize lactic acid bacteria (LAB) in pickles and investigate the effect of lactic acid fermentation on phenolic compounds in peony flowers. Six strains of <i>Lactobacillus plantarum</i> and one strain of <i>Weissella</i> identified by 16S rRNA sequencing met the safety standards confirmed by metabolite safety assessment and antibiotic resistance analysis. NPLP12 exhibited excellent fermentation characteristics and its tolerance, adhesion, and antioxidant indicators all demonstrated its potential as probiotics and starter. After fermentation with NPLP12, the content of total phenols (15.2 %) and flavonoids (22.7 %) in the liquid extract of peony flowers was significantly increased, and the antioxidant activity was also enhanced. Ultra Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS) analysis confirmed that apigenin 7-O-glucoside and kaempferol-3-O-glucoside were key synergistic components. This study provides a reference for the screening of peony flower fermentation strains, the utilization of peony flower resources and the development of functional peony flower fermentation beverages.