Optimization of Oil Loading and Starch-Protein Ratio for Encapsulation of Flaxseed Oil Using Response Surface Methodology

Microencapsulation of flaxseed oil (FSO) was studied with tapioca starch (TS)-whey protein isolate (WPI) combination as a shell material using spray drying to optimize the process variables for preparation of spray dried microcapsules of flaxseed oil using TS-WPI coating material combination. Box Behnken design (3k) was used to design the experimental runs of selected independent variables (three level), which included starch: protein ratio (1: 1, 3: 1 and 5: 1) and oil loading (20%, 25%, and 30%) of total solids in feed mixture and inlet air temperature (IAT: 160 °C, 170 °C, and 180 °C) of spray dryer. Response surface methodology (RSM) was used for response analysis and for optimization of process variables for maximizing encapsulation efficiency and minimizing peroxide value (PV). Quadratic models were significantly fitted to the responses with high coefficient of determination (R2). The optimum conditions predicted based on numerical optimization were 20% oil loading, 2.40: 1 TS: WPI ratio and 170 °C drying air temperature, respectively. The results of responses observed after confirmatory experiment were in good agreement with the predicted responses of the model.