A lipo-dipeptide (C13-lysine-arginine, C13-KR) was designed as a potential emulsifier with good emulsifying properties under acidic condition. Compared with two traditional emulsifiers (whey protein isolate and Tween 80), C13-KR emulsion had the minimum mean size but the highest zeta potential (around +100 mV). Moreover, C13-KR emulsion showed better stability against environmental stresses, such as high salt concentrations and high temperature. The C13-KR particles had the fastest move rate around 400 Hz when it attained an equilibrium state. Furthermore, C13-KR emulsifier could sharply reduce the interfacial tension and had the lowest tension value at the oil/water interface. The interfacial tension of C13-KR emulsifier was only 3.6 mN/m (0.5% w/v). In conclusion, the lipo-dipeptide C13-KR could be considered as an emulsifier to produce emulsion under acidic condition.
Keywords: emulsifiers; emulsion stability; environmental stresses; lipo-dipeptide C-KR; ultrasound.