Microencapsulation of casein hydrolysates: Physicochemical, antioxidant and microstructure properties

摘要

The present study has aimed to evaluate the microencapsulation process of the different casein hydrolysates and to assess the physical properties (moisture content, water activity, bulk density, tapped density, solubility and hygroscopicity), antioxidant activities, chemical structure (FTIR), microstructure and bitterness-masking of the spray-dried powders. The microencapsulation process was done using a laboratory spray-dryer and maltodextrin (DE = 18) as the carrier agent. The obtained results indicated the hygroscopicity of the casein hydrolysates was significantly reduced after microencapsulation process (P 0.05). By evaluating the antioxidant properties, it became clear that the DPPH free radical scavenging activity, ABTS radical scavenging activity, hydroxyl radical scavenging activity, reducing power, Fe2+ and Cu2+ chelating activity were maintained as 90.4-98.5%, 77.5-91.6%, 77.2-93.1%, 95.2-99.6%, and 76.7-98.4% after the spray-drying process, respectively. FTIR spectrometry proved the presence of the hydrolysates in the structure of the microcapsules. The scanning electron microscopy images showed the production of hollow particles with a matrix-type structure. In addition, sensory evaluation of the pastilles fortified with microencapsulated and free hydrolysates suggested that the spray-drying has been effective in reducing the bitterness of these compounds.