Biodegradable soy-polymer delivery system for slow-release of micronutrients and biologically active compounds

The aim of this thesis was to study polymeric properties of soy proteins in order to develop controlled release system for micronutrients or biologically active compounds. Two types construct of soy protein-polymers were studied: thermo-set cast films and cold-extruded pellets. Generally, the solubility of soy protein-polymers in either film or pellet is greater at pH 7 than at pH 3 and the solubility of films is greater than pellets. The solubility of non-cross-linked samples in trypsin is increased much more than in pepsin compared to buffer solutions alone. Cross-linking soy films and pellets with glutaraldhyde or dialdehyde starch effectively reduced the solubility either in pH 3 and pH 7 buffer alone or in trypsin and pepsin solutions. The release rate of phosphorus from the matrix pellet of soy protein isolates with phosphorus fertilizer was tested either in soil or in a vitro digestive system-rumen fluid from cows.