The operation of microencapsulation via spray drying is often applied to flavors, natural pigments and oxidable oils in order to protect them against volatilization and oxidation. Despite the successful use in many applications, the retention of such compounds is normally evaluated case-by-case, without the knowledge of the effective improvement of the barrier properties as a function of the components used. In edible films, with the same base formulation of the particles, the influence of the individual components on the barrier properties is already elucidated. However, due to the difficulty of analysis, this information has not been validated for particulate systems. In this research project, performed in collaboration with Prof. Dr. Gary Reineccius (Univ. Minnesota), it is proposed to investigate the influence of the lipid and protein phase on the barrier properties of the particles and on the retention of the active. Different classes of surface agents (gelatin, whey protein isolate and modified starch) will be mixed with maltodextrin to evaluate their influence on oxygen permeation and migration of volatile compounds. For this evaluation two oils will be used as active principle: a fixed oil susceptible to oxidation (fish oil) and a volatile oil (orange essential oil). The determination of the barrier properties is the great challenge of the project. The permeation of water vapor and oxygen in films of the same composition as the particles will be determined and these data will be correlated with measurements of void space and molecular motility of the particles, determined by means of positron annihilation life spectroscopy (PALS), porosity, microscopy, DSC, x-ray diffraction and indirectly through oxidative stability and release assays.
News published in Agência FAPESP Newsletter about the scholarship: