Physical Stability and Interfacial Properties of Oil in Water Emulsion Stabilized with Pea Protein and Fish Skin Gelatin

This study aimed to investigate the physical stability and interfacial properties of oil-in-water (O/W) emulsions stabilized with fish skin gelatin (FG) and pea protein (PP) at pH 3. Physico-chemical properties, elemental composition and SDS-PAGE of the proteins were determined in the first part of this work. Emulsions were prepared at different ratio FG: PP (100: 0-75: 25-50: 50-25: 75-0: 100) by mechanical stirring followed by ultrasound treatment. Higher physical stability was observed in the presence of FG (ratio 100: 0), where the O/W were stable similar to 50 h. An average hydrodynamic diameter < 1 mu m was found for all the emulsions except for the ratio 75: 25, where it was 2.8 mu m. The presence of the protein on the O/W interface was explored by confocal laser scanning microscopy whereas the thermal properties of the protein ratios were analyzed by differential scanning calorimetry. The lower denaturation temperature was observed for ratio 50: 50, which was founded at similar to 89 degrees C, whereas the denaturation temperatures for the others O/W emulsions were in the range of 99 and 108 degrees C. A predominant viscous behavior was observed for all the ratios while a slight decrease of the surface tension was observed in the presence of PP. The equal mixing of FG with PP showed an increase in the emulsifying properties of PP forming a more stable emulsion with lower particle size.