Abstract: In order to improve the stability and functional properties of casein-derived bioactive peptides (CP) in yogurt, the peptides were microencapsulated using sodium alginate and sucrose fatty acid esters as the wall material, which was determined based on encapsulation efficiency and peptide loading, and the developed microcapsules were applied in yogurt. Scanning electronic microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) proved the successful encapsulation of the peptides. The microcapsules had good sustained release properties, and the release rate was (62.57 ± 1.17)% after 3 h of intestinal digestion. The microencapsulated bioactive peptides improved the water-holding capacity, hardness and viscosity of yogurt, and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability of yogurt with the bioactive peptides was (63.73 ± 1.97)%. The microencapsulated bioactive peptides were not degraded during yogurt fermentation by lactic acid bacteria, and the functional properties of yogurt were enhanced by addition of the bioactive peptides.

Key words: casein hydrolysate; bioactive peptides; microcapsules; yogurt; antioxidant