Biocontrol potential of 1-pentanal emitted from lactic acid bacteria strains against Aspergillus flavus in red pepper (Capsicum annuum L.)

Abstract

Aflatoxin contamination poses a significant threat to world health and has caused huge economic losses to countries worldwide. The application of volatile organic compounds (VOCs) has emerged as one of the most promising strategies for the prevention and control of fungal contamination. In this work, first, VOCs produced by six lactic acid bacteria (LAB) strains exhibited excellent inhibition activity against the growth of Aspergillus flavus. Then, gas chromatograph-mass spectrometry (GC-MS) identified 32 compounds from captured VOCs of LAB. In addition, partial least square (PLS) analysis revealed that 1-pentanal, 1-pentanol, glycidol, 1- hexanol and 1-heptanol are the compounds most related to antifungal effect in volatile profiles, demonstrating excellent inhibition against A. flavus on both potato dextrose agar (PDA) plates and red pepper powder in next antifungal assay. In vitro experiments revealed 1-pentanal to have the highest antifungal activity of the five VOCs, with a minimal inhibitory concentration (MIC) of 40 μL/L. Scanning electron microscopy (SEM) proved that exposure to 1-pentanal caused A. flavus to exhibit mycelial shriveling and failed conidia formation. Meanwhile, our results showed that fumigation with 1-pentanal had no adverse effect on the quality of red pepper powder. These results indicate that 1-pentanal, identified as the component with the highest antifungal activity in this study, is a promising bio-preservative with the potential to prevent A. flavus contamination of red pepper.