The influence of carrier material on some physical and structural properties of carrot juice microcapsules

- Microencapsulated carrot juices has low water activity.
- The carrier influences the amount of carotenoids microencapsulated.
- Better maintenance of carotenoids in GA and WPI powder samples was observed.
- Tg of microencapsulated carrot juice can be evaluated by DSC or TD-NMR.

This study investigates the effect of carrier type on the physical and structural properties of microcapsules of pure carrot juice. Low-crystallised maltodextrin (MD), gum arabic (GA), mixtures of MD and GA (1:1; 2:1; 3:1) and whey protein isolate (WPI) were used as carriers. Microencapsulation was carried out in a spray-drier at inlet air temperature of 160 °C. Powders were investigated for dry matter, water activity, diameter, carotene content and hygroscopicity. In addition, differential scanning calorimetry (DSC) and time domain nuclear magnetic resonance (TD-NMR) were applied to analyse microcapsules glass transition temperature (Tg).Carrot powders with GA used as a carrier material resulted in better carotenoids retention and higher stability of powders in terms of higher Tg, lower aw and good hygroscopic properties. However, all powders showed a low aw (below 0.26) and high dry matter content (98-99%) indicating a good potential for protection of microencapsulated carotenoids during the storage.