CHARACTERIZATION OF PHYSICAL PROPERTIES, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF SPRAY-DRIED EXTRACTS OF CUSTARD APPLE PEEL (Annona squamosa L.)

Abstract

Spray-dried extracts of custard apple (Anona squamosal L.) peel were studied in different concentrations (10%, 12%, 14%, 16%) of maltodextrin (DE 15-20) as a carrier agent, using drying-inlet temperature of 150⁰C, flow rate of 500-600mL/h, and pressure of 3-4 bar. Physical properties, total polyphenol content (TPC) and antioxidant activity of encapsulated powders are key factors to screen the concentration of carrier agent. Antimicrobial activity of the final spray-dried powder was evaluated against 6 bacterial strains causing food poisoning diseases, including Staphylococcus aureus, Bacillus cereus, Salmonella typhimurium, Escherichia coli, Shigella sp. and Listeria sp. The results showed that 12 % maltodextrin was the best concentration for the encapsulation of custard apple extract with the TPC of 46.47 ± 0.45 mg GAE/g CK; antioxidant activity of 253.32 ± 2.52 µmol TE/g CK (DPPH), 578.96 ± 6.07 µmol TE/g CK (ABTS); and minimum inhibitory concentrations (MIC) of  S. aureus, B. cereus, Shigella sp. and S. typhimurium were 800mg/mL while those of  Listeria sp., and E. coli were 400 mg/mL.