FLUIDIZED-BED SYSTEM FOR WHEY PROTEIN FILM COATING OF PEANUTS

Complete peanut‐surface coverage and strong adhesion are necessary for whey protein‐based oxygen barrier coatings to be totally effective in reducing the oxidative rancidity of peanuts. Peanuts coated with a fluidized‐bed coating system attained practically complete coverage, and coating efficiency results were consistent and reproducible. Addition of surfactant to the coating solution improved whey protein coating efficiency on blanched/roasted peanuts coated with a bench‐scale fluidized‐bed coating system. A lower level of surfactant addition to the coating solution was required to attain complete coverage, compared with previous studies on dip coating and pan coating of peanuts. Addition of surfactant to the coating solution and peanut preroughening both imparted good coating adhesion for fluidized‐bed‐coated peanuts. Compared with pan coating, fluidized‐bed coating required application of a greater amount of coating solution because of the loss of coating solution to the fluidized‐bed column wall during spraying. Overall, fluidized‐bed coating required a shorter processing time and provided the peanuts with better coating efficiency and adhesion. These results suggest that a fluidized‐bed coating system is a viable alternative coating process for whey protein coating of peanuts.