Physicochemical and functional properties of yoghurt supplemented with bioactive low-molecular-weight casein hydrolysates

The present study was carried out to investigate the effect of fortification of natural yoghurt with different concentrations (0, 0.2, 0.5 or 1% w/v) of bioactive low-molecular-weight casein hydrolysates (1-3 kDa) on the physicochemical and functional properties of yoghurt during 21 days of storage at 4 °C. Casein hydrolysates significantly promoted development of acidity with improved microrheological characteristics of yoghurt gel during fermentation, and adding 1% (w/v) casein hydrolysates reduced fermentation time by 50 min when compared with the control. The fortified yoghurt exhibited reduced syneresis, improved textural and rheological properties, enhanced antioxidant and antidiabetic activities, and maintained higher bacterial viability during the refrigerated storage. Increased bioactivities were found after simulated gastrointestinal digestion. Fortified samples were characterized with high levels of flavour compounds. The results highlight the potential of employing these newly developed bioactive casein hydrolysates as functional ingredients.