Quality improvement of grounded peanut using superheated steam treatment by the inhibition of microorganisms, lipase, and aflatoxin

There are many problems of peanuts, such as lipid instability, high microbial content, and aflatoxin. In this study, effect of superheated steam (SS) treatment on the security quality of grounded peanut (GP) was evaluated. Results indicated that concentrations of total bacteria, mold, and Bacillus spp. were maximum reduced 99.26, 100, and 98.57%, respectively. SS processing led to 70% lipase activity and 90% POD activity reduction at 215°C for 2 min, which induced lower AV and PV after 70 days of storage compared to untreated GP. The moisture content dramatically decreased, but color of GP was not affected significantly. SS processing (215°C) was first to apply on degradation of total aflatoxin and aflatoxin B1. Therefore, SS is a novel and effective way to remove the microorganisms and aflatoxin in GP, as well as inhibiting lipase and peroxidase activities so as to improve the lipid stability. Novelty impact statement Mold could be totally inactivated by SS treatment at 140°C for 4 min or over 160°C for 1 min. Compared to untreated GP, SS processing at 140, 160, 180, and 215°C for 4 min could decrease 24.73, 25.52, 30.57, and 35.25% of AV, respectively. SS processing at 215°C for 1 min reduced 77.6% of AFs and 75.7% of AFB1.