Effects of the use of proteins on the barrier properties of particles produced by spray drying

Abstract

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 often evaluated on case by case, without the necessary understanding of the effective improvement of the barrier properties of the particles as a function of the components used. In this research project, performed in collaboration with Prof. Dr. Gary Reineccius (Univ. Minnesota), it is proposed to investigate of the influence of the lipid and protein phase on the barrier properties of the particles and on the retention of the active. Emulsions composed by maltodextrin (MD), different surface agent components (SAC) - modified starch (MS), gelatin (GE) or whey protein isolate (WPI) -, and a volatile oil as active, represented by orange oil, will be produced and dried in spray dryer to evaluate the influence of the SAC on the protection against oxygen permeation and migration of volatile compounds. The permeation of water vapor and oxygen through particles will be evaluated by adsorption isotherms and oxipres methodology, respectively. These data will be correlated with measurements of void space and molecular mobility of the particles, determined by means of positron annihilation life spectroscopy (PALS), porosity, microscopy, x-ray diffraction, FTIR and indirectly through oxidative stability and release assays.