Effect of maltodextrin and gum Arabic carriers on the physicochemical properties and antioxidant activity of spray-dried casein hydrolysates

In this research, enzymatic hydrolysis of casein was performed using alcalase and pancreatin enzymes under optimal conditions. Then, the effect of type and combination of maltodextrin and gum Arabic carriers on physicochemical properties (moisture content, water activity, bulk density, tapped density, solubility, hygroscopicity), maintaining antioxidant activity (ABTS, DPPH and hydroxyl radical scavenging activities, reducing power, Fe2+ and Cu2+ chelating activity), morphology and mean particle size of spray-dried casein hydrolysates was evaluated. The results showed that moisture content, water activity, bulk density, tapped density and solubility as equally were affected by type and combination of carrier (P< 0.05). The hygroscopicity value of casein hydrolysates decreased significantly after the microencapsulation process. The antioxidant activity of the hydrolysates varies depending on type of enzyme. For example, ABTS and hydroxyl radical scavenging activities of pancreatin hydrolysates were higher than alcalase types (P< 0.05). The combination of maltodextrin and gum Arabic showed the best effect in maintaining of ABTS radical scavenging activity (92.72-94.93%), DPPH (98.47-98.94%), hydroxyl radical scavenging activity (88.59-94.95%), reducing power (98.94-99.65%), Fe2+ chelating activity (98.38-98.61%) and Cu2+ chelating activity (82.86-98.12%). The images of the electron microscope showed the presence of particles with different size distribution and wrinkles. In addition, the samples produced with gum Arabic had a larger particle size than maltodextrin. Finally, the results of this study showed the effectiveness of spray-drying process on the production of microencapsulated hydrolysates with desired physical, stability and antioxidant properties.