The primary objective of this research was to comprehensively evaluate the applicability and utility of alkyl modified silica matrices for flavor encapsulation. These silicate matrices were generated through a sol-gel process by co-hydrolyzing and co-polymerizing a simple alkoxysilane and a long chain alkylalkoxysilane. In the first study, a response surface model was designed to determine the statistically significant variables of the sol-gel process on the encapsulation efficiency of a hydrophobic flavor molecule (limonene). In Study 2 and 3, two formulations that exhibited the highest encapsulation efficiency from Study 1 were employed to encapsulate a complex flavor mixture consisting of compounds (diacetyl, methyl propanal, methyl pyrrole and damascenone) having a wide range of physicochemical properties. As the losses of flavor compounds in silicate matrices were high during drying, the matrices were blended with an emulsifying starch before freeze drying. Flavor mixture consisting of compounds was incorporated into medium chain triglycerides (MCT's), limonene and neat before being added into the carrier matrix. We examined the efficacy of these proposed matrices by conducting a comprehensive evaluation of the stability of encapsulated flavor compounds in silica: starch blends during storage and examining the release profiles of these compounds in a food application. While hydrophilic silica blends outperformed the hybrid silica blends in the absence of the solvent, the latter performed better in the presence of solvents. Further, the differences in release properties between matrices were primarily attributed to the differences in % retention during drying; the effect of which may have surpassed the effect of flavor solvents or manufacturing formulation/process.
University of Minnesota Ph.D. dissertation. December 2008: Major: Food Science. Advisor: Prof. Gary Reineccius. 1 computer file (PDF), appendices 1-9.
The evaluation of silica based self-assembling matrices for flavor encapsulation.
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