Effect of carvacrol on the inhibitory of gas-producing spoilage microbes and volatile flavor in fermented pepper (Capsicum annuum L.)

Abstract

In this study, two gas-producing spoilage microbes, namely CQ17 and CQ22, were isolated from fermented pepper. Combining the physiological and biochemical characteristics, molecular biological identification, and specific colony morphology, CQ17 was identified as Pichia manshurica while CQ22 was identified as Lentilactobacillus buchneri. Subsequently, our findings indicated that the CQ17 and CQ22 strains exhibited resistance to high temperature, low-pH, and high salinity environments. Meanwhile, our findings revealed that carvacrol, a commonly utilized preservative, exhibited remarkable inhibitory activities against Pichia manshurica and Lentilactobacillus buchneri with the EC50 values of 0.28 and 0.68 mg/L respectively, effectively suppressing the growth of gas-producing strains to prolong the shelf life of fermented pepper. Simultaneously, volatile components of the fermented pepper were analyzed using HS-GC-IMS technology resulting in identification of 55 volatile flavor compounds including acids, alcohols, esters, aldehydes, ketones, alkenes, and other compounds. Among them, (R/S)-linalool, 3-methyl-1-butanol acetate butanoic acid ethyl ester, 2-methyl butanoic acid ethyl ester, and ethyl 2-methylpropionate were identified as crucial components contributing to sensory attributes in fermented pepper as well as (E)-3-hexen-1-ol and l-Pentanol exhibited the highest VIP values and can be considered as the best reliable markers for differentiating fermented pepper samples with the addition of carvacrol as a preservative.