Emulsions Stabilized by Microbial Polysaccharide FucoPol: Production and Characterization

Mestrado em Engenharia Alimentar - Instituto Superior de AgronomiaThe present work is focused on the production and characterization of oil in water emulsions stabilized with a bacterial exopolyssacharide (EPS), named FucoPol, produced by the bacterium Enterobacter A47 using glycerol as carbon source. The stabilizing ability of FucoPol was studied using aqueous biopolymer solutions with concentrations of 0.5%, 1.0% and 1.5% w/w, and sunflower oil, in ratios oil/water (O:W): 20:80, 40:60, 60:40 and 80:20. It was observed that the majority of the emulsions, except the proportions 80:20, showed no phase separation after 24 hours of maturation at 4 ºC. Emulsions had a shear thinning behavior, and it was observed that, for the same oil/water ratio, the apparent viscosity increased with increasing of FucoPol’s concentration in the aqueous phase. It was also found that either the apparent viscosity or viscoelastic properties remained quite similar over 72h, indicating the presence of stable emulsions during this period of time. The effect of FucoPol on the production of low-fat emulsions was also studied using pea protein (3% w/w) as emulsifier. It was studied the effect of FucoPol and oil concentrations on the characteristics of the emulsions obtained, keeping constant the emulsifier concentration. It was observed that for oil concentrations between 20% and 40% w/w, there’s a significant increase in viscosity with increasing of FucoPol’s concentration, but for oil contents between 40% and 60% w/w, no significant influence was observed. Still, for the whole range of oil concentrations tested it was observed that an increase in FucoPol concentration allows to produce emulsions with a stronger internal structure. Therefore, it was concluded that the adding of this biopolymer allows to produce emulsions with a fat content below 60%