Application of gamma and electron-beam irradiations for aflatoxin B1 decontamination in peanut: effects on physicochemical properties and food safety

Infected peanuts were subjected to various radiation doses (0–10 kGy) to evaluate their effects on microbial populations, physicochemical parameters (including phytosterols, fatty acid composition, volatile compounds, total soluble protein, and malondialdehyde levels), and aflatoxin B1 (AFB₁) content. Both gamma and electron beam irradiation effectively reduced AFB₁ levels (529.40 ± 3.40 µg/kg) and microbial contamination, with gamma irradiation achieving more significant reductions 85.9% (74.70 ± 2.15 µg/kg) at 2 kGy and complete elimination at 4 kGy, compared to electron beam treatment (58.01% and 97.59% reduction at 2 (222.30 ± 4.10 µg/kg) and 4 kGy (12.73 ± 0.75 µg/kg), respectively), which required higher doses (6 kGy). Gamma irradiation also significantly inhibited Aspergillus flavus growth at 2 kGy. However, doses above 2 kGy -particularly at 10 kGy- increased malondialdehyde levels, indicating lipid oxidation that could deteriorate peanut quality and affect consumer acceptance, and color indices, leading to a darker appearance. Total soluble protein increased, and a change in the electrophoretic pattern of proteins of the treated peanuts was detected at a dose of ≥ 4 kGy. Although formal sensory analysis was not performed, changes in volatile compounds and color indices were used as indicators of sensory quality. Notable reductions in phytosterols and volatile compounds affected the sensory characteristics of peanuts. Additionally, analysis of the fatty acid profiles revealed that neither irradiation method significantly diminished the total fatty acid content at a dose of 2 kGy, but certain unsaturated fatty acids were affected by increasing irradiation dose. This study underscores the potential of gamma and electron-beam irradiation at 2 kGy as effective strategies for enhancing the safety of peanuts while maintaining their quality, albeit with considerations for dosage optimization to balance efficacy and sensory attributes.