• Response Surface Methodology optimized Delonix regia microencapsulation. • Coating concentration and stirring time were key efficiency parameters. • Optimal alginate and chitosan microcapsules achieved high efficiency. • SEM and FTIR analyses confirmed successful microcapsule formation. • Microencapsulation preserved the strong antioxidant activity of the extract. The bioactive compounds naturally present in plants are highly valuable due to their biological properties. However, these compounds are prone to degradation as they tend to be unstable. Microencapsulation is an effective method used to enhance their stability and protect them from environmental factors, thereby preserving their bioactivity. In this study, the indicator being optimized is the encapsulation efficiency of flamboyant (Delonix regia) leaf extract in alginate and chitosan microcapsules. Optimization and design of pairs of independent variables for testing encapsulation efficiency can be determined using Response Surface Methodology (RSM). The research design was carried out through the CCD (composite central design) model in RSM using Design Expert software version 13. The research variables are coating concentration (X1) and stirring time (X2), and the expected response is encapsulation efficiency (Y). Microcapsules produced under the highest encapsulation efficiency conditions for each polymer were then further identified and characterized. Microencapsulation of flamboyant extract was performed using biodegradable polymers, alginate and chitosan, via a freeze-drying technique. Coating material concentration and stirring time affected the percentage encapsulation efficiency (EE) of the microcapsules. The optimum conditions for alginate microcapsules were a coating concentration of 1.75% (w/v) and a stirring time of 37.5 min, yielding an EE of 82.26%. In addition, chitosan concentration of 0.12% (w/v) and a stirring time of 75 min resulted in the highest EE of microcapsules with 84.13%. Microcapsules in these optimum conditions still retained high antioxidant activities toward DPPH radicals with the IC 50 values of less than 100 μg/mL. Leveraging its predictive and optimization capabilities, RSM holds significant potential in facilitating the development and optimization of microencapsulation processes.
Safitri et al. (Wed,) studied this question.