Interfacial behavior of coconut (Cocos nucifera L.) globulins at different pH: Relation to emulsion stability

Abstract

For better understanding the emulsification mechanism of coconut globulin (CG) at different pH, the relationship between interfacial behavior and emulsion stability (O/W) of unheated and heated (90 °C, 30 min) CG with different pH (3-11) were investigated. The dynamic interfacial tension of CG exhibited the lowest value at pH 11, followed by pH 9, 3, 7, and 5. CG had the best interfacial adsorption at pH 5 but had an interfacial desorption at pH 11. All groups displayed decreased adsorption after heating. The CG at pH 5 had the highest dilatational elasticity modulus (Ed), followed by pH 3, 7, 9, and 11. The Ed trend of heated CG was consistent with the unheated samples but significantly decreased. Under high frequency and amplitude perturbation, the CG at pH 11 had a higher dilatational modulus (E). The CG showed a better interfacial behavior that contributed to a better emulsion stability at pH 3 whether been heated or not. The illumination of relation between interfacial behavior and emulsion stability is of great significance in promoting the application of CG as an emulsifier.