Encapsulation of oils from sour cherry kernel and berry seeds by protein-protein complexes

In this study, the encapsulation of raspberry seed oil (RSO) and sour cherry seed oil (CHSO) which have high amount of Omega 3 and 6 fatty acids by heteroprotein complexes and coacervates was investigated. In the first part of thesis, formation of complexes and coacervates was examined between two oppositely charged globular proteins, lactoferrin (LF) and pea protein isolate (PPI) with a specific PPI/ LF molar ratio at room temperature. Structural aspects of the electrostatic complexes probed at different length scales were investigated as a function of pH by means of dynamic light scattering, small angle X-ray scattering (SAXS), turbidity measurements, transmission electron microscopy (TEM) and atomic force microscopy (AFM). In an optimum narrow range of pH 5.0-5.8, a viscous liquid phase of complex coacervate was obtained whereas soluble complexes were formed between pH 6.2-7.5. In the second part, emulsions were prepared with different methods at optimum complex (pH 7) and coacervate (pH 5.4) conditions. The most appropriate method was determined as formation of complexes and coacervates at the last stages of encapsulation based on droplet size, droplet charge, emulsion stability and microstructure analysis. The effect of oil concentrations on (2-10 wt%) droplet size and rheology of emulsions was evaluated in the third part of thesis. Emulsions were later freeze dried to evaluate loading capacity, encapsulation efficiency, loading efficiency, moisture content and encapsules morphology. The results revealed that increasing oil concentration cause significantly effect on encapsulation efficiency and particle morphology (p<0.05). Encapsules produced at optimized conditions (6 wt% oil, 2 wt% protein) with RSO and CHSO were evaluated for their physicochemical properties and oxidative stability. They were stable at 45°C during storage. Pure oil showed higher lipid oxidation which indicates protective effect of encapsulation on oxidative stability. Based on the results, it was found that heteroprotein complexes and coacervates can be used to encapsulate omega rich oil.