Effect of various calcium concentrations on the interactions between β-lactoglobulin and epigallocatechin-3-gallate

β-Lactoglobulin (β-lg) is a globular protein accounting for 11% of all milk proteins. Recently, the use of β-lg as vehicles for the delivery of bioactive compounds such as green tea catechins has been explored. The objective of this study was to determine the impact of various calcium concentrations on the interactions between β-lg and epigallocatechin-3-gallate (EGCG), the most abundant green tea catechins. Five different calcium concentrations were tested for their effect on complex formation and characteristics. Our results showed that when EGCG was present, the increase in calcium concentration influenced ζ-potential and more importantly, drastically increased particle size. The presence of EGCG was essential to the formation of larger complexes, stabilized mainly by electrostatic interactions via calcium bridging when calcium is present.