Optimization of Persian lime essential oil (Citrus latifolia) microencapsulation through spout fluidized bed drying

In the food industry, fluidized bed drying encapsulation is important due to its protective effects on sensitive oily materials such as essential oils. In this study, Persian lime essential oil (EO) was encapsulated at ratios of 10%, 20%, and 30% using wall materials including maltodextrin (25%, 50%, and 75%) and whey protein concentrate (10%, 20%, and 30%) through the fluidized bed drying method. Then, using response surface methodology, the encapsulation yield, encapsulation efficiency, moisture content, hygroscopicity, bulk density, tapped density, particle density, flowability index, Hausner ratio, porosity, solubility, inhibitory power, and release in buffer and simulated saliva were optimized. The results indicated that a higher concentration of essential oil and whey protein concentrate along with a medium concentration of maltodextrin led to an increase in encapsulation yield, encapsulation efficiency, bulk density, tapped density, particle density, flowability index, solubility, inhibitory power, and release while decreasing moisture content, hygroscopicity, and porosity. Therefore, the optimization of dependent and independent variables showed that a medium concentration of maltodextrin and a high concentration of whey protein concentrate in wall materials, with a high concentration of EO, are required to achieve the desired optimized properties of the final microcapsule (such as high antioxidant activity and low moisture content). According to the results, the optimized conditions included using lime essential oil, maltodextrin, and whey protein concentrate at 29.68%, 41.28%, and 30%, respectively. Since microencapsulation using a fluidized bed drying allows for low-temperature microencapsulation, it effectively preserved the antioxidant properties of lime essential oil (with a DPPH radical scavenging percentage of 63.64% in run 18) during processing in this study.