Flavor release from spray-dried amorphous matrix: Effect of lactose content and water plasticization

Glass-forming carbohydrates are widely used as matrix for encapsulation of nutrients and bioactive compounds. In this study, encapsulation systems with lactose/whey protein isolate (WPI) mixtures (4:1,1:1, and 1:4), or WPI as wall materials and ethyl butyrate as core material were prepared by spray drying. The effects of lactose content and water plasticization on encapsulation efficiency and flavor release were investigated. Wall material consisting of lactose/WPI (4:1) mixture had significantly (P< 0.05) higher encapsulation efficiency. The flavor retention in powders did not have significant decrease with equilibration at 033 a(w), while it was dramatically decreased at 0.54 a(w) and 0.65 a(w) as a result of lactose crystallisation. Mechanical properly study showed that the molecular mobility and free volume of encapsulation systems with higher lactose content increased more significantly with increasing water content, which accelerated the diffusion of flavor molecules. Those results may use in the assessment of protection and release characteristics of flavor components in formulated systems. (C) 2016 Elsevier Ltd. All rights reserved.