Influence of temperature and ionic conditions on the rheology and droplets characteristics of winged bean protein stabilized oil-in-water emulsion

To explore the potential of winged bean seed protein as a food ingredient, an oil-in water emulsion, [25% (w/w), pH 3] stabilized by the protein (5% solution) was prepared by high-pressure homogenizer and subjected to heat (35-75 degrees C), cold (4-8 degrees C) and NaCl (1-4%) conditions alone or in combination, and their physicochemical stability to the treatments was assessed by measuring creaming, droplets characteristics and rheology. Result showed a slight increase in mean droplet size at treatment up to 35 degrees C and 1-2% NaCl. At treatment of 55 degrees C and 3% NaCl, significant increases in mean droplet size were observed, droplet distribution changed from monomodal to bimodal, advanced flocculation and coalescence up to 75 degrees C, leading to poly-disperse distribution. No flow was observed until a yield value (sigma(0)) was overcome. At 1% NaCl, the sigma was 13Pas compared to 21Pas at 3-4% NaCl, and above 35 degrees C treatment, emulsions had high apparent viscosity and exhibited Bingham plastic model resulting from increased droplets sizes.