Whey Protein Coating Efficiency on Mechanically Roughened Hydrophobic Peanut Surfaces

ABSTRACT:  Mechanical roughening of commercially blanched-and-roasted peanuts efficiently improved whey protein coating efficiency. However, increased coating coverage varied significantly among peanuts, likely due to variable change of peanut surfaces during commercial processing and storage before coating. Coating efficiency was further improved and was more consistent on mechanically roughened freshly blanched-and-roasted peanuts compared to the commercially blanched-and-roasted peanuts. The improved coating efficiency without large variation on mechanically roughened freshly blanched-and-roasted peanuts may be the result of avoiding the re-formation of a waxy cuticle layer on peanut surfaces, which occurs during storage between commercial blanching/roasting process and the coating application. Scanning electron microscope (SEM) micrographs of treated peanuts confirmed the effect of roughening, as well as disruption of the parenchyma cell structure of peanuts and the creation of channels that could allow oil migration to the peanut surface and subsequent formation of a waxy layer with long enough storage.