Effect of Chlorine Dioxide Bacteria-Reducing Pretreatment on Quality of Fermented Chili Paste

Abstract

Microorganisms play a critical role in determining the quality of fermented chili paste. However, spoilage microorganisms residing on the surface of chili peppers can compromise sensory attributes and reduce edibility. This study aims to adopt chlorine dioxide to reduce spoilage microorganisms prior to fermentation, and the effects on chili paste quality were systematically evaluated. The pretreatment (soaking in 75 mg/L chlorine dioxide solution for 10 min) significantly reduced microbial richness and abundance on chili surfaces. Physicochemical analysis indicated that this reduction facilitated fermentation, as evidenced by increased total acid and decreased levels of nitrite, capsaicin, and reducing sugars. Inoculation with lactic acid bacteria (LAB) further enhanced flavor development by promoting the accumulation of lactic acid, malic acid, and acetic acid, while suppressing the formation of bitter amino acids. These changes contributed to a sweet, floral, and fruity aroma profile. In total, 64 volatile compounds were identified, including 23 characteristic aroma components such as ethanol, citronellol, acetoin, phenylethyl alcohol, and ethyl acetate. Fermentation following sterilization and LAB inoculation resulted in a higher content and more layered composition of volatile flavor components. Overall, bacteria-reducing pretreatment markedly improves the quality and flavor complexity of fermented chili paste. The problems such as the long fermentation period and insufficient flavor of chili paste under the conditions of unsterilized pretreatment and natural fermentation have been solved.

Practical Applications: Few reports address the combination of chlorine dioxide pretreatment with targeted LAB inoculation in chili paste preparation. Bacteria-reducing pretreatment greatly improved the safety quality of fermented chili paste. Bacteria-reducing pretreatment enriched the flavor of chili paste, and provided fruity, floral and sweet aroma.