Valorization of Custard Apple (Annona squamosa L.) peel waste: Effect of drying methods on physicochemical properties, bioactive compounds, and application in functional cream biscuits

Custard apple peel, an agro-industrial waste, represents a rich source of bioactive compounds with potential applications in functional food development. In the present study, custard apple peel powder was prepared using tray and vacuum drying methods and evaluated for its physicochemical, phytochemical, and structural properties. The results indicated that CAP powder is rich in fiber, protein, minerals, and bioactive compounds. Ultrasound-assisted extraction was performed using different ethanol–water ratios, among which a 60:40 ratio yielded the highest total phenolic content (1245.12 ± 0.17 mg GAE/100 g). Structural characterization using FTIR, XRD, and SEM confirmed the presence of functional groups and amorphous nature of the powder. ICP-MS analysis revealed that heavy metal contents were within permissible limits, confirming its safety for food applications. CAP powder was further incorporated into cream filling for biscuit preparation, and sensory evaluation indicated that 4% incorporation provided optimal acceptability. The study demonstrates a sustainable approach for valorization of custard apple peel waste into value-added functional food products.