Functionalization of sodium caseinate fortified with blackcurrant concentrate via spray-drying and freeze-drying techniques: The nutritional properties of the fortified particles

Abstract

Novel protein ingredients were produced by encapsulating blackcurrant concentrate (BC) with sodium caseinate (NaCas) through spray- and freeze-drying strategies. The effects of encapsulation strategies and addition of BC on the proximal compositions, colour profiles, and nutritional properties (including total phenolic content, antioxidant capacity, predicted in vitro glycaemic, and inhibitory activity towards α-amylase) of the powders, were evaluated. The protein content of NaCas-BC powder was more than 80 g/100 g. Addition of BC significantly changed the colour profiles, increased the total phenol content, and the antioxidant capacity of the powders. Freeze-dried NaCas-BC extract (20076.30 ± 212.24 μg/100 g) had significantly higher total anthocyanin content than spray-dried NaCas-BC extract (17236.25 ± 31.17 μg/100 g) (p < 0.01). The encapsulation efficiency of freeze-dried NaCas-BC powder was obviously higher (p < 0.01) than spray-dried NaCas-BC powder. Addition of BC reduced the reducing sugar released from NaCas powder during the in vitro digestion. This could be due to its inhibitory α-amylase activity. Taken together, NaCas-BC powder can be utilized as high protein ingredient to reduce glycaemic response and increase protein content of starchy food. Freeze-drying might be a better encapsulation strategy than spray-drying, regarding its more effective preservation of the bioactive components.