Protect peanut kernels from Aspergillus spp and their mycotoxins during storage by aqueous extract of carob pulp

Abstract

Recently, the trend of many studies to replace synthetic antifungal commonly used during storage with natural antifungal; Plant extracts has been one of the most promising strategies for this purpose. Therefore, this study aimed to evaluate the aqueous extract of the carob pulp (AECP) at 1.5, 2.5, and 5 mg/ml on the growth of some toxigenic Aspergillus species, and its effectiveness as an anti-mycotoxigenic (aflatoxins (AFs) and ochratoxin A (OTA) during storage red peanut kernels (RPKs) for 90 days. The results indicate that the increased concentration of AECP, the area of inhibition zone increased with all treatments. As well, the strain of Aspergillus ochraceus was more affected by AECP than Aspergillus aflatoxiformans followed by Aspergillus parasiticus which recorded (15.7 ± 0.4 mm), (13.4 ± 0.5 mm), and (11.9 ± 0.4 mm) at 5 mg/ml. Respectively. While, the lowest inhibition was shown with Aspergillus flavus at three concentrations of AECP. The impact of AECP on the accumulation of total AFs and OTA during storage of RPKs infected by A. parasiticus and A. ochraceus, respectively, for 90 days. The results showed that the active compounds in the AECP at 5 mg/ml can protect RPKs for 45 days without detecting any amounts of AFs and OTA. After 90 days, the inhibition percentages for the four types of aflatoxins (AFB1, AFG1, AFB2, AFG2) and OTA compared with positive control samples were 85.1, 76.5, 86.5, 84.2, and 87.5%, respectively. Finally, AFB1 recorded the lowest inhibition percentages of all treatments; on the contrary, it was OTA.