Spray-dried microencapsulation of orange essential oil using modified rice starch as wall material

Essential oils are widely employed in food industry as natural flavors, however, these compounds are very difficult to handle due to they are very susceptible to oxidation and volatilization during process and storage generating undesirable flavors, therefore, it is necessary to use a protection method as microencapsulation. Chemical and thermo-mechanically modified rice starch was used as wall material together with native rice starch, maltodextrin, and protein to microencapsulate orange essential oil by a spray-drying technology. Microcapsules obtained were characterized in encapsulation efficiency (%EE), encapsulation yield (%YE), solubility, humidity (%), water activity (A(w)), and color difference (E). Through a surface response analysis, best formulations were selected and evaluated by its microestructure and stability of encapsulated essential oil. Results showed that the best encapsulating agent was the one with modified rice starch as predominant ingredient (>50%) of the wall material, showing higher efficiency than commercial encapsulating ingredients. Practical applicationsMicroencapsulation is widely employed in food industry due to its ability to protect a compound of interest from adverse conditions that can generate decomposition of it or, in terms of flavor compounds, the generation of undesirable aroma and flavor characteristics. A lot of wall materials have been used to develop microencapsulation, however, starch is one of the main natural wall materials employed in microencapsulation by spray-drying due to its high encapsulation efficiency. Rice starch is proposed in this study because is an abundant raw material, has the property of generate spherical aggregates and, together with another wall materials (maltodextrin and protein), can generate a resistant wall material with high encapsulation efficiency. Furthermore, the modification of rice starch involves a less employment of reactives, due to the thermomechanical process, obtaining a starch with more affinity to nonpolar compounds (essential oil), low viscosity, and solubility at room temperature (25 degrees C); which made this, an environmental friendly process. The procurement of the best wall material formulation suitable for encapsulation by spray drying, is of primary importance in order to preserve the quality and integrity of the encapsulated essential oil by reducing the presence of oxidation byproducts, increasing the shelf life and improving with this, its application inside a food matrix. Once the best wall material formulation is obtained, it can be used for the encapsulation of any type of essential oils used in the food industry.