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Controlling the rheological properties of oil phases using controlled protein-polysaccharide aggregation and heteroaggregation in water-in-oil emulsions

Iqbal, Shahid, Xu, Zichong, Huang, He, Chen, Xiao Dong
Food hydrocolloids 2019 v.96 pp. 278-287
droplets, emulsions, gels, heat, heat treatment, hydrocolloids, kappa carrageenan, lipid content, margarine, microparticles, modulus of elasticity, pH, pectins, polyglycerol polyricinoleate, polymers, sodium alginate, sodium chloride, soybean oil, trans fatty acids, viscosity, whey protein isolate
In this study the influence of oppositely charged protein and polysaccharide microspheres on the rheological properties of single and mixed water-in-oil emulsions was investigated. Single and mixed aqueous phases of 40 wt % W/O emulsions were prepared by dispersing, under controlled conditions (pH 3.5, 100 mM NaCl), Whey Protein Isolate (WPI) and three different kinds of polysaccharides: High Methoxy Pectin (HMP), kappa Carrageenan (kC), and sodium alginate (SA). The oil phase consisted of 8 wt % Polyglycerol polyricinoleate (PGPR) in soybean oil. At pH 3.5, WPI carries positively charged groups, while polysaccharides have negatively charged groups. It was observed that before heating, single W/O emulsions had higher complex shear modulus and shear viscosity than mixed emulsions, which suggested stronger protein-polysaccharide interactions in single droplet systems. After subjecting to a thermal treatment (90 °C, 30 min), the rheological properties of the mixed emulsions were higher than for equivalent single emulsions, suggesting denser gel network formation between opposite charged emulsion droplets, especially in the WPI-HMP mixed system. The data from this study may be useful for development of reduced-fat margarine and spreads with low saturated and trans fat content.