Microencapsulation technique helps to protect the core materials from deterioration, thereby improving the bioavailability of active compounds. In microencapsulation, the wall properties determine the encapsulation efficiency, and better results can be achieved when a mixture of multiple wall materials is used. This study aimed to optimize the wall material composition of pomelo peel (Citrus maxima (Burn.) Merr.) microcapsules prepared by spray drying technology to achieve the best values of polyphenol recovery and encapsulation efficiency. Response surface methodology was employed and a Box-Behnken design was used to investigate the effects of four independent variables, including the concentrations of resistant maltodextrin, pectin, β-cyclodextrin, and gum arabic. The concentration of the feeding liquid, and spray drying inlet and outlet temperatures were fixed at 30 °Bx, 180 °C, and 65 °C, respectively. The results showed that the optimized wall material composition consisted of 52.66% maltodextrin, 0.92% pectin, 5.30% β-cyclodextrin, and 6.28% gum arabic. Using this formula, the polyphenol recovery yield was found to be 78.86%, while the encapsulation efficiency was 77.78%, which agreed well with the predicted values of 78.90% and 77.67%. These results strongly indicate that the optimized wall material composition proposed in this study may be beneficial in the encapsulation process.

Keywords:
Box-Behnken design; Citrus maxima (Burn.) Merr.; microencapsulation; polyphenol; response surface methodology; wall material composition