Reduction of aflatoxin B1 and Ochratoxin A in cocoa beans infected with Aspergillus via Ergosterol Value
Aflatoxigenic and ochratoxigenic isolates were used to contaminate cocoa beans in this study and Ergosteol Values (EV) were assessed by means of visual inspection, Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) and Gas Chromatography?Mass Spectrometer (GC?MS), respectively. Different concentrations of Aframomum danielli essential oils at 500, 1,000, 1,500, and 2,000 ppm were used to treat the infected samples. It was found that aflatoxin B1 (afB1) and Ochratoxin A (OTA) correlated with EV and all correlated with cocoa bean infection and positively r = 0.80 and 0.79. Toxic afB1 in the Aspergillus flavus contaminated cocoa beans reduced from 1.4 ng g10−1 at 1,000 ppm essential oil and reached 0.08 ng g10−1 at 2,000 ppm. The afB1 reduction efficiency with A. danielli was found to be 94.3% while ergosterol reduced by 78.5%. The OTA and the EV of other cocoa bean sample varied according to the contaminating species and its OTA production capacity. The active components of A. danielli such as the mono-terpenes, alkaloids and phenolic acids in the essential oils might have been responsible for the reduction in afB1, OTA and EV as evidenced in this study.
Keywords: afB1, aflatoxin B1, Aspergillus, cocoa beans, ergosterol contamination, OTA, Ochratoxin A, toxic metabolites, natural spice extract, fungal contamination, food contamination, mycotoxins