Effect of protein oxidation on the stability of peanut beverage

Abstract

Protein oxidation of peanut beverage and their stability during the storage were investigated. To further investigate the relationship between protein oxidation and peanut beverage stability, peanut protein isolate (PPI) was oxidized by peroxyl radicals derived from 2,2ʹ-azobis (2-amidinopropane) dihydrochloride (AAPH), and the emulsion properties stabilized by oxidized PPI were evaluated. During the storage, protein oxidation happened in the peanut beverage, accompanied by deteriorating their stability. Low storage temperature would lighten the oxidation extent and the peanut beverage instability. High roasting pretreatment of peanut kernels before making peanut beverage would enhance the protein oxidation. Emulsion stabilized by oxidized PPI had larger mean droplet size and lower surface charge. Microstructure of PPI stabilizing emulsion showed that emulsions stabilized by PPI of overoxidation underwent severe droplet aggregation during storage. Protein oxidation was an important factor influencing stability during peanut beverage storage.