# Effects of a novel salt-tolerance Lactiplantibacillus plantarum on the physicochemical properties and volatile profiles of broad-bean paste

## TL;DR

A new salt-tolerant bacteria improves the flavor and quality of broad-bean paste by boosting good smells and reducing bad ones.

## Contribution

A novel halotolerant Lactiplantibacillus plantarum strain YQ1 was isolated and shown to enhance BBP fermentation quality.

## Key findings

- Fermentation with L. plantarum YQ1 increased phenethyl alcohol by 436% and benzyl alcohol by 553%.
- Undesirable compounds like benzaldehyde decreased by 87% with this strain.
- Genomic analysis revealed genes linked to stress tolerance and aroma compound production.

## Abstract

Broad bean paste (BBP) is a traditional Chinese condiment whose spontaneous fermentation often leads to unstable quality and safety concerns. This study isolated a novel halotolerant Lactiplantibacillus plantarum YQ1 from BBP as a starter culture. The strain exhibited exceptional salt tolerance (18% NaCl), acid and bile resistance, and a favorable biosafety profile. In BBP fermentation, it significantly reshaped metabolites, increasing tartaric and lactic acids, and promoting threonine accumulation. Volatile analysis demonstrated substantial improvements in desirable aroma compounds, with phenethyl alcohol increased by 436.37% and benzyl alcohol increased by 553%. Meanwhile, undesirable benzaldehyde, 3-methylbutanoic acids and 2-methylbutanoic acid decreased by 87%, 81%, and 62%. Genomic analysis further identified key genes underpinning these traits, as well as phenylalanine metabolism and alcohol-derived aroma biosynthesis. These findings highlight the potential of L. plantarum YQ1 as a starter culture to enhance the flavor, minimize off-flavors, and stabilize fermentation for high-salt BBP production.

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•L. plantarum YQ1 exhibited exceptional salt (18% NaCl), acid, and bile tolerance.•L. plantarum YQ1 fermentation increased phenethyl alcohol by 436%.•L. plantarum YQ1 promoted beneficial metabolites like lactic acid and threonine.•Genomics elucidated the mechanisms underlying stress tolerance and flavor formation.

L. plantarum YQ1 exhibited exceptional salt (18% NaCl), acid, and bile tolerance.

L. plantarum YQ1 fermentation increased phenethyl alcohol by 436%.

L. plantarum YQ1 promoted beneficial metabolites like lactic acid and threonine.

Genomics elucidated the mechanisms underlying stress tolerance and flavor formation.