Studying the effect of electromagnetic field (EMF) and presence of salt on electrostatic interactions between β-lactoglobulin (β-lg) and gum Arabic

The aim of this study was to understand the effect of electromagnetic field (EMF) and ionic strength on the electrostatic interactions between beta-lactoglobulin(beta-lg) and gum Arabic (GA). Therefore, different EMF intensities (5.2, 6.4, 7.6, 8.8, and 10 mT) and NaCl concentrations (30, 35, and 40 mM) were used. The turbidimetric results showed that an increase in the EMF intensity shifted the curves to more acidic regions in comparison to the control sample. In other words, more interactions occurred in the EMF-treated samples while addition of salt distinctly decreased the turbidity and inhibited the interaction. The particle size observations were evaluated by static light scattering machine (SLS). The results showed that the particle size significantly increased (up to 0.753 +/- 0.01 mu m) by raising the EMF intensities to 10 mT. The addition of NaCl at a concentration of 30 mM showed a slight increase in the particle size diameter. By increasing the salt concentration to 35 and 40 mM, a decrease in the particle diameter was observed which could be due to the reduction in protein/polysaccharide reaction as a result of the prohibiting effect of salts. SEM micrographs revealed almost the same structures in the EMF-treated and untreated samples. However, more aggregation was observed in EMF-treated samples. The presence of salt also established small aggregations. This study showed that EMF can have interesting effects on protein/polysaccharide interactions and formation of particles used as delivery systems.