Effect of edible coating containing Williopsis saturnus var. saturnus on aflatoxin production in peanuts

Peanut (Ayrachishypogaea L.) in the Fabaceae family is composed of a high amount of oil. Peanuts are consumed as human food and animal feed. Mold growth on peanuts usually occurs before and after harvesting, during drying, sorting and storage due to unsuitable conditions. Mycotoxins were produced by mold as secondary metabolite .Aspergillus flavus is the most common mold on peanuts producing a mycotoxin called aflatoxin which is cancerogenic, tetragenic and hepatoxic. Williopsis saturnus var. saturnus killer yeast has been informed to have an antagonistic effect on mold growth in several studies. In this study, the effect of W. saturnus var. saturnus yeast alone or with whey protein concentrate (WPC) coating on the growth of A. flavus and aflatoxin production on peanuts was investigated. In this purpose, peanut samples were coated with WPC edible films with or without W. saturnus or yeast without coating at a concentration of 107kob/ml. Following drying, the peanuts were contaminated with A. flavus (103 kob/ml) and dried at 40 ºC. After drying, they were packed and stored at 25°C for 84 days. The number of W. saturnus and A. flavus were determined throughout the storage period. Amount of aflatoxin, weight loss, water activity, TBA number, colour, protein, moisture of the peanut samples were also observed. The results showed that during 84 days of the storage period; number of W. saturnus var. saturnus stayed stable. Application of coating with W. saturnus and only yeast solution significantly reduced growth of A. flavus and aflatoxin production in the peanuts samples (p<0,05). The chemical properties and color of all peanut samples did not change with coating and yeast application (p<0.05). Application of edible films based on whey protein slightly decreased the oxidation of peanut samples (p<0,05). Treatment of coating containing W. saturnus antagonistic yeast did not cause a significant change on water activity value (p<0.05). The sensory characteristic of peanuts samples coated with different coating solutions did not show a significant difference (p<0.05). As a conclusion, application of whey protein coating containing W. saturnus var. saturnus on the peanut samples have a significant potential to inhibit aflatoxin production. Keywords: Edible film, killer yeast, peanut, aflatoxin