Modulating the rheological properties of oil-in-water emulsions using controlled WPI-polysaccharide aggregation in aqueous phases

In this study we determined the effect of whey protein isolate-polysaccharide combinations in aqueous phases, on modulating the rheology and microstructural properties of 20 wt % oil-in-water emulsions. The aqueous phases of three emulsions consisted of combinations of 4 wt % whey protein isolate (WPI) and 0.5 wt % Locust bean gum, iota-carrageenan (IC), or chitosan separately (pH 4, 100 mM NaCl), while the oil phase was soybean oil . It was observed that all heated emulsions had higher moduli and viscosities than unheated systems. This behavior could be due to greater protein-polysaccharide interactions after thermal treatment, leading to highly viscous and elastic materials. Observed microstructures also supported the rheological results, and showed that thermal treatment led to denser gel-networks formation in heated emulsions, particularly in WPI-IC system. This study may provide significant impact in the production of semi-solid O/W emulsified foods with improved texture and rheology, but reduced total fat content.