Microencapsulation of anthocyanin-rich black soybean coat extract by spray drying using maltodextrin, gum Arabic and skimmed milk powder

Abstract

Black soybean coat is insufficiently valorised food production waste rich in anthocyanins. The goal of the study was to examine physicochemical properties of spray dried extract of black soybean coat in regard to carrier materials: maltodextrin, gum Arabic, and skimmed milk powder. Maltodextrin and gum Arabic-based microparticles were spherical and non-porous while skimmed milk powder-based were irregularly shaped. Low water activity of microparticles (0.31–0.33), good powders characteristics, high solubility (80.3–94.3%) and encapsulation yields (63.7–77.0%) were determined. All microparticles exhibited significant antioxidant capacity (243–386 μmolTE/g), good colour stability after three months of storage and antimicrobial activity. High content of total anthocyanins, with cyanidin-3-glucoside as predominant, were achieved. In vitro release of anthocyanins from microparticles was sustained, particularly from gum Arabic-based. These findings suggest that proposed simple eco-friendly extraction and microencapsulation procedures could serve as valuable tools for valorisation and conversion of black soybean coat into highly functional and stable food colourant.

Keywords:

• Black soybean coat
• anthocyanin-rich extract
• spray drying
• microencapsulation
• microparticles
• colourant

Acknowledgements

This work is supported by the projects of Ministry of Education and Science and Technological Development, Serbia, N^o46010 and N^o31069. Authors are grateful to Dr Vesna Perić and Dr Mirjana Srebrić (Maize Research Institute, Breeding Department, Belgrade-Zemun, Serbia) for providing black soybean genotype used in this study.

Disclosure statement

No potential conflict of interest was reported by the authors.