Comparative analysis of freeze drying and spray drying methods for encapsulation of chlorophyll with maltodextrin and whey protein isolate

Abstract

Chlorophyll (Chl) is a healthy green pigment that is very unstable. So, chlorophyll microcapsules were fabricated using maltodextrin and whey protein isolate as carriers and freeze-drying (FD) and spray-drying (SD) as encapsulation methods. The microcapsules obtained by the freeze-drying method (FDM) had smaller particle sizes (1.087–0.165 µm) and higher ζ-potential (−10.6 to −18.3 mV) than the spray-drying method (SDM) (3.420–0.285 µm) and (−9.5 to −10.7 mV) respectively. FTIR, XRD, and DSC studies showed that the inclusion of Chl within microcapsules and FDM had a higher melting point (150.12 °C) than SDM (125.03 °C) and Chl (115.66 °C). FD was more effective in protecting Chl from changes in pH (pH 2 to 8, Chl retention; 49.67 %–91.28 %) and light (Chl retention; 38.12 %) than SD. Therefore, due to preserving Chl and increasing its stability, FDM could be a promising approach to use as a natural food colourant.

Keywords

• Chlorophyll
• Encapsulation
• Freeze-drying
• Spray drying
• First-order kinetic model