Preparation and characterization of whey protein isolate-chlorophyll microcapsules by spray drying: Effect of WPI ratios on the physicochemical and antioxidant properties

Whey protein isolate-chlorophyll (WPI-CH) microcapsules at different WPI ratios via spray drying were created to improve water solubility and biological stability of chlorophyll. Samples at a higher ratio of WPI resulted in a lower moisture content (1.14 ± 0.12% to 2.47 ± 0.09%), higher chlorophyll encapsulation efficiency (98.34 ± 0.03% to 99.76 ± 0.02%) and greater chlorophyll solubility (79.29 ± 0.07% to 82.24 ± 0.03%). The results of fluorescence and FT-IR spectra showed that the pyrrole ring of chlorophyll became bound to the hydrophobic residues of WPI leading to a change in the crystalline structure of chlorophyll, probably due to the formation of soluble complexes of WPI-CH. In addition, the antioxidant activity of fresh WPI-CH samples, and those stored for 6 months, increased by 19.75% and 18.51% respectively compared to WPI (p < 0.05). Therefore, WPI-CH prepared by the higher ratio of WPI can be used as a potential natural food additive because of its good antioxidant activity and physicochemical properties, especially water-solubility and stability.