Characterization of antioxidant and antimicrobial properties of spray-dried extracts from peanut skins

This study aimed to produce dried extracts from peanut skin using spray-drying technology for application as a natural antioxidant and antimicrobial in foods. The extracts were spray-dried with 10, 20, or 30% of maltodextrin (carrier) at different temperatures (130, 150, and 170 degrees C), to establish the best conditions to produce the powders. The powders were characterized with regards to moisture, hygroscopicity, particle size, and solubility, and the stability of phenolic compounds was evaluated throughout 120days at 25 degrees C. The antimicrobial and antioxidant activities of powders were also evaluated. Powders produced at higher temperatures and 30% of maltodextrin presented the best results for hygroscopicity, solubility, and particle size, and the powder produced at 150 degrees C with 30% of maltodextrin showed the high stability of phenolic compounds during storage. All powders presented remarkable antioxidant activity and showed bacteriostatic activity against Listeria monocytogenes, and bactericidal activity against Staphylococcus aureus. Taken together, these results indicate that the best conditions (of those tested) for spray drying peanut skin extracts were at 150 degrees C and with 30% of maltodextrin. The resultant powders have technological potential due to the high stability, good physical properties, and remarkable antioxidant/antimicrobial activities, which could be applied as natural additives to improve food quality. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.