Microencapsulation of Black Carrot Anthocyanins by Conventional and Three-Nozzle Spray-Drying: Effect on Storage Stability and Bioaccessibility

The black carrot (Daucus carota L.) is a source of anthocyanins (AT), especially acylated forms, valued for their color and antioxidant properties, which are linked to the prevention of diseases caused by oxidative stress. However, their low robustness to pH and temperature limits their application. This work aimed to evaluate the effect of spray-drying microencapsulation of black carrot juice (BCJ) on the stability and bioaccessibility of AT. Spray-drying (SD) was used as an encapsulation technique with conventional (two-nozzle) and three-nozzle spray-drying, and maltodextrin (MD) was used as the encapsulating agent; sodium alginate (SA) was used as the outer layer. The optimal SD conditions were 150 °C and a BCJ:MD ratio of 1:2. Two systems were obtained: BCJ-MD and (BCJ-MD)-SA, both with encapsulation efficiencies above ~90%. During storage for 198 days at 60 °C, both systems significantly reduced the degradation constant compared to free juice, following pseudo-first-order kinetics. However, a critical finding was that in vitro bioaccessibility was significantly higher in the conventional BCJ-MD (~88%) compared to the BCJ-MD-SA system (~44%). These results suggest that maltodextrin alone is a more effective strategy for maximizing the in vitro bioaccessibility of black carrot anthocyanins, thereby providing a stable, highly bioaccessible healthy ingredient for the food industry.