Encapsulation of hydrophilic and hydrophobic flavors by spray drying

The encapsulation of flavors is the important process in food industry. The encapsulation of flavors with spray drying and the flavor release from spray-dried powder were reviewed. The hydrophobic flavor was in the form of emulsion before spray drying. Therefore, the researches were mainly related to the forming of emulsion which wall material containing emulsifier properties are required. On the other hands, the hydrophilic flavor was mainly related to the antioxidant and coloring flavor powder. The hygroscopicity of powder and their stickyness during the spray dryer were important points to improve which the remaining of hydrophilic flavors were less concerned. The morphologies, and flavor release behavior are important physical properties of the flavor encapsulated powder. Especially, the correlation equations for the flavor release are summarized in the relation with Avrami or Weibull equation. The glass transition temperature is important to estimate the collapse of the powder and the permeation of the powder matrix to flavor compounds. The flavor release (mass transfer of flavor) rate is affected by temperature difference (T-Tg). In this review, recent researches are summarized in the flavor encapsulation in spray drying, especially for tropical flavor encapsulation.