Encapsulation and Characterization of Custard Apple (Annona squamosa) Peel and Seed Extract: A Novel Delivery Approach

Abstract

Objective: To extract and encapsulate phenolic compounds from custard apple peel and seed. Methodology: Phenolic compounds were extracted from the dried and powdered peel and seed of ripe custard apple using 80% aqueous ethanol with powder to solvent ratio 1:10 under ultrasound-assisted conditions of 80% amplitude for 10 min. Both extracts were encapsulated using maltodextrin and gum acacia as wall material using spray drying (SD) and freeze drying (FD). SD was conducted with inlet temperature of 170°C, atomization air pressure of 20 psi, and feed flow rate of 5 mL/min. FD was conducted at -80°C trap temperature. The encapsulates were analyzed for physicochemical properties, encapsulation efficiency, core-wall interactions, and morphological features, and the performance of encapsulation techniques was compared. Results and discussion: The peel extract showed higher phenolic and flavonoid content compared to seed extract. The encapsulates prepared by FD reported lower moisture content and lower values of Hausner ratio (1.32 ±0.03) and Carr’s index (24.68 ±1.60) indicating better flowability compared to the SD counterparts. FD also reported higher values for encapsulation efficiency of peel (67.63%) and seed extract (72.66%) compared to SD which is also reflected in the higher antioxidant activity of FD encapsulates. The higher encapsulation efficiency in FD can be attributed to the low temperature operation. The FTIR spectra of all samples confirm the successful encapsulation of phenolic compounds. The microstructure revealed that SD formed spherical microparticles with smooth surface with slight indentations. On the other hand, FD produced flaky particles with sharp edges. Though FD showed higher encapsulation efficiency and better flowability, SD demonstrated superior microstructure suitable for enhanced stability and better release of active ingredients. The encapsulates demonstrate strong potential for application in nutraceutical and functional food, supporting the value addition and sustainable utilization of fruit processing waste and by-products.