Recent Topics on Spray-Drying Encapsulation of Food Materials — An Overview —

Spray drying is one of the most common and economical techniques typically employed in the microencapsulation of valuable food ingredients. Because most food core materials are generally hydrophobic, the feed solution to the spray dryer is normally an emulsion. The quality of microencapsulated powder is influenced by several operations and phenomena during spray drying, such as atomization and drying kinetics of the droplets into solid particles. In this review, selected research on the drying operations conducted over the last ten years as well as the properties of the produced powder is discussed. The items specifically reviewed are the spraying of uniform droplets, the breakage of emulsion droplets during atomization, simulation of drying a droplet by the reaction engineering approach, the storage stability of core ingredients, estimation of the surface-oil content, and measurement of the encapsulation state of the core ingredient in the dry particles by confocal laser scanning microscopy.