Effect of aflatoxin B1 detoxification on the physicochemical properties and quality of ground nut meal

Abstract

Aflatoxin B1 (AFB1) in groundnut meal (GNM) was detoxified up to 97% by a combination of enzymatic and physical processes. Finely-powdered defatted groundnut meal containing 1.2 mM AFB1 per 100 g of meal was first detoxified up to 53% with 10 IU of horseradish peroxidase enzyme in the presence of hydrogen peroxide and then the meal containing 12–15% (wb) moisture was treated with microwave radiation at 1 kwt for 15 min to achieve a final 97% detoxification. A comparison was made of the treated and untreated groundnut meal quality with respect to their nitrogen solubility, total nitrogen and protein nitrogen contents, and protein composition. Rat feeding experiments were performed to study the effect of detoxification processes on ground nut meal quality as indicated by the mortality, food efficiency ratio and food conversion rate. Mean weight gains of the rats receiving the treated meals were essentially comparable to those for animals receiving aflatoxin-free diets. Overall, nitrogen-solubility of the enzyme-treated meal increases in the pH 2–6 range. Polyacrylamide gel electrophoretic patterns of the protein did not show any notable changes. Amount of protein nitrogen in the meal increased after the enzymatic treatment. Mortality rates of the young animals were high when they were fed untreated meal containing aflatoxin. Resistance increased with age, which was evidenced by the relatively lower mortality rate of the rats after prolonged feeding of aflatoxin-infected meal.