Effect of Microencapsulation by Spray Drying and Freeze Drying Technique on the Antioxidant Properties of Blueberry (Vaccinium myrtillus) Juice Polyphenolic Compounds

Abstract

Blueberry juice with high polyphenol concentration was spray-or freeze-dried using different coating materials: HP--cyclodextrin and -cyclodextrin. The quality of the obtained powders was characterised by their anthocyanin content, total polyphenols and antioxidant capacity. SEM was used for monitoring structures and size (2-20 m) of the microparticles. The losses of total phenolic compounds during spray-drying reached 76-78% on average, while these of anthocyanins about 57%. Freeze-dried powders showed better retention values of anthocyanins, which was about 1.5-fold higher than for the spray-dried counterparts. All blueberry preparations studied were characterised by very high radical scavenging activity.