Microencapsulation of polyphenols-rich extracts from African Peach (Sacocephalus latifolius sm.) roots through spray drying

Many medicinal plants rich in phenolic compounds have many different uses in pharmaceutical industries. Nevertheless, these biomolecules are vulnerable to degradation upon extraction. A potential way for preventing this degradation is microencapsulation. This study aimed to determine the optimal conditions for producing Sacocephalus latifolius (sm.) microcapsules extracts demonstrating the best encapsulation efficiency (EE) of polyphenols and highest antioxidant activity using sweet potato dextrin. Therefore, Response Surface Methodology has been used for optimization of microencapsulation process through spray drying considering drying temperature (120–160 °C), inlet air flow rate (60–80 m3/h) as well as encapsulating agent (5–15 g/g of extract) as factors. The Total phenolic content of extract was 69.68 ± 3.98 mg GAE/100 mg of extract. Furthermore, microencapsulation results demonstrated that an increase in drying temperature and encapsulating agent respectively correlated with an increase in process yield and decrease in moisture content together with water activity of microcapsules. Principal component analysis (PCA) assessed correlations between microencapsulation process conditions and the responses. PCA grouped conditions into four clusters, with two ungrouped. The optimized conditions of microencapsulation polyphenolic-rich extracts were found to be drying temperature of 157 °C; inlet flow rate of 78.65 m3/h and a dextrin of 14 g/g of extract. Experimental values of process yield, EE of polyphenols and DPPH radical scavenging activity obtained were 87.04%, 74.78% and 83.67% respectively with a moisture content and aw of 2.80% and 0.201 in microcapsules respectively. Particle size analysis and SEM demonstrated that the microcapsules had spherical shape, no crack on surface with average size of 21.75 μm and Span value of 1.257. These results are applicable for extending the use of African peach in formulations of herbal medicine through microencapsulation.