Microencapsulation of spinach extract using binary blends of biopolymers: A comparison between freeze drying and spray drying approaches 

Abstract

This investigation sought to evaluate the relative efficacies of freeze drying (FDM) and spray drying (SDM) methodologies in the microencapsulation of spinach extract, as a source of chlorophylls (CHL), utilizing varying concentrations and ratios of Arabic gum and maltodextrin. Alterations observed in the FTIR spectra substantiated the successful incorporation of CHL within the carriers’ matrix, with the drying method exerting no discernible influence. The mean values for powder yield and encapsulation efficiency in FDM samples at 25% total solid content (TS) were 19.24% and 5.28% greater, respectively, than those of spray-dried samples, while SDM microcapsules exhibited significantly enhanced storage stability. FESEM analysis revealed the considerable impact of drying method, carrier type, concentration, and ratio on both the size and surface properties of samples. An increase in TS from 25–35% resulted in a significant increase in mean particle size for SDM powders from 7.19 µm to 10.96 µm, while FDM samples exhibited an increase in surface roughness. In conclusion, both methodologies demonstrated the capacity to preserve CHL; however, given the significance of energy consumption and process duration at an industrial scale, we propose that SDM represents a suitable approach by producing CHL microparticles with extended shelf-life and favorable processibility.