RESUMO
Oil-in-water emulsions (20%/80%, w/w) were stabilised by two types of ß-caseins (1 g/L, w/w) extracted by rennet coagulation from camel and cow's milk, respectively. Both extracts were treated under different ranges of pH (3.0, 6.0 and 9.0) and temperature (25, 65 and 95 °C for 15 min) before emulsification. The emulsifying properties of the proteins were studied by surface and interfacial measurements. Results show that the emulsifying activity (EAI) of camel ß-casein is higher than the bovine protein. Yet, both proteins exhibited heat stability and nonsignificant effect of temperature was reported. Conversely, a significant effect of pH on camel ß-casein was recorded: at pH 6.0, the lowest values of EAI were measured and explained by the formation of micellar protein structure. Under such conditions, camel ß-casein is therefore a novel emulsifying protein with high potential to stabilise oil-in-water interfaces which provides numerous applications for the food chemistry field.
