Enhanced flavor and biogenic amine safety of salt-reduced Doubanjiang through co-inoculated fermentation with Pediococcus acidilactici and Zygosaccharomyces rouxii.

Abstract

Salt-reduced fermentation of Doubanjiang is often accompanied by quality deterioration and safety concerns related to excessive biogenic amine (BA) accumulation. This study integrated chemometrics, flavoromics, metabolomics, and sensory evaluation to investigate the effects of salt reduction and co-inoculation with Pediococcus acidilactici and Zygosaccharomyces rouxii on physicochemical properties, volatile metabolites (VMs), non-volatile metabolites (NVMs), and sensory profiles of Doubanjiang. Results showed that BA levels in salt-reduced samples reached 875.0-1400.0 mg/kg, with histamine exceeding the recommended limits, whereas co-inoculation reduced the total BAs by 14.75-56.27%, and histamine was undetectable. Compared with salt-reduced samples, co-inoculated fermentation further increased the total concentration of VMs by 9.00-93.01%, primarily driven by a significant enrichment of ester compounds. A total of 226 VMs were identified, among which esters, alcohols, and aldehydes were the major discriminative compounds, among which 16 showed significant aroma contributions (relative odor activity values ≥1). Metabolomics profiling further identified 122 differential NVMs (P < 0.05), mainly comprising amino acids, organic acids, and amines. Sensory analysis revealed that salt reduction intensified sweaty and sour attributes and decreased overall scores compared with traditional fermentation, whereas co-inoculation effectively reversed these undesirable traits by enhancing ester- and floral-related sensory attributes. These findings demonstrate that salt reduction accelerates substrate degradation and promotes the excessive generation of BAs, while appropriate co-inoculation effectively suppresses and transforms these compounds, thereby ensuring safety and improving flavor quality. This study provides systematic insights and mechanistic support for the safe production and quality enhancement of salt-reduced fermented foods.