Effects of Carriers on Spray-dried Flavors and Their Functional Characteristics

Encapsulation is an effective method to keep the quality of and avoid changes in flavors or essential oils due to oxidation, heating, volatilization, or chemical interactions. This study aims to microencapsulate key flavorings by traditional wall materials, namely, gum arabic (GA), maltodextrin (MD) and sodium caseinate (SC) and evaluate the effects of different wall materials on the properties of the flavor microcapsules.

The emulsions of flavor compounds (linalool, citral, orange oil, allyl caproate and isoamyl acetate) were prepared using GA, SC and MD as carriers with different concentrations and then encapsulated in powder form by a spray dryer. Physical properties, including encapsulation efficiency, viscosity, emulsion stability and moisture, were studied before and after the spray drying process. Moreover, the morphology and extent of the nonenzymatic browning (NEB) of powder particles were performed using a scanning electron microscope (SEM) and a chroma meter. The effect of encapsulation on flavor retention and chemical composition was evaluated using gas chromatography-mass spectrometry (GC-MS).

Orange oil shows the maximum retention efficiency (84.5-97.9%), whereas isoamyl acetate is less retained during drying (44.4-72.5%) compared with other volatile compounds. Increasing the concentration of GA provides the highest retention for all aroma compounds and improves the viscosity and the emulsion stability of spray-dried powder. The presence of MD as the main encapsulating agent enables the formation of several homogeneous capsules with a good spherical shape and a smooth surface, according to SEM. The NEB is observed intensively in encapsulated samples containing citral and orange oils, whereas the least browning occurs in isoamyl acetate microcapsules.

Wall material formulation affects the retention, morphology and physical properties of the encapsulated flavors, which can be used in food or nutraceutical powder premixes.