Correlation between microbial communities and key odourants in fermented capsicum inoculated with Pediococcus pentosaceus and Cyberlindnera rhodanensis

BACKGROUNDFermented capsicum (i.e. pickled pepper) is one of the most popular fermented vegetables. However, the effect of inoculated microbial fermentation on pickled pepper is not yet fully understood. RESULTSCyberlindnera rhodanensis J52 with a rich ester flavour and Pediococcus pentosaceus AL with a strong inhibitory effect on foodborne pathogenic bacteria were selected to prepare single- and double-strain fermented capsicum under low salt (< 10 g L-1 sodium chloride) conditions. The inhibition zone of P. pentosaceus AL against Escherichia coli was up to 44 mm in diameter. Biochemical indicator analyses found that co-fermentation of P. pentosaceus AL and C. rhodanensis J52 changed the contents of vitamin C and short-chain fatty acids. Analysis of microbial diversity and volatile metabolome showed that 125 microbial species and 72 volatile compounds were detected, and P. pentosaceus was the dominant bacterium that inhibited the growth of other bacteria, while C. rhodanensis was the fungus that contributed the most to flavour. Correlation analysis between microorganisms and flavour compounds showed 725 correlations, and 124 microbial species may have participated in the formation of 69 compounds. Furthermore, 10 and 29 correlations were detected between P. pentosaceus AL or C. rhodanensis J52 and flavour compounds, respectively. Among them, 3-methyl-1-butanol acetate is speculated to be the main substance affecting the flavour of fermented capsicum by inoculation with C. rhodanensis J52. CONCLUSIONThe inoculation of P. pentosaceus and C. rhodanensis had a significant impact on the microbial community and volatile compounds of fermented capsicum and helped to improve its organoleptic qualities. (c) 2022 Society of Chemical Industry.