Radio frequency roasting promotes the degradation of aflatoxin B1 and achieves better quality of peanuts (Arachis hypogaea L.)

Abstract

Peanuts contaminated with aflatoxin B1 (AFB1) possess serious health risks. Radio frequency (RF) roasting was used for decontamination of AFB1 in peanuts. The effects of RF roasting on AFB1 degradation and peanuts quality were investigated under varied electrode gaps (90, 100, 110, and 120 mm), target temperatures (120, 130, 140, and 150 °C) and initial moisture contents (10%, 15%, 20%, and 25%). The results showed that corn grit as the assistant material was superior for improving the heating uniformity of peanuts. With increasing target temperature and moisture content, the degradation rate of AFB1 increased significantly from 20.05% to 75.33% and 35.52%–66.09%, respectively, while electrode gap had no significant effect on the degradation of AFB1. Compared with hot air roasting (140 °C), RF roasting increased the degradation rate of AFB1 by 18%, with lower acid value and less tissue damage. Fourier transform infrared spectrum and scanning electron micrographs revealed the development of lipid hydrolysis, Maillard reaction and protein denaturation in roasted peanuts. RF roasting under 110–120 mm electrode gap, 140 °C target temperature, and 15%–20% initial moisture content was optimal considering both AFB1 degradation and products quality. Overall, RF roasting provides a new insight for the degradation of AFB1 in foods and crops.