Olive oil emulsions formed by catastrophic phase inversion using bacterial cellulose and whey protein isolate

Low energy emulsification methods have gained ground the recent years because of their simplicity in use and low cost. Our work was focused on the use of catastrophic phase inversion (CPI) technique for the formation of olive oil emulsions in the presence of bacterial cellulose (BC) and whey protein isolate (WPI). Firstly, phase behavior of the biopolymers was established. Then, surface and interfacial tension, as well as viscosity measurements of the WPI and BC solutions and their mixtures were carried out. Based on these findings, emulsions were prepared at pH 3.8 with an oil to water ratio of 10:90. The aqueous phase, containing BC and WPI at various concentrations or a mixture of both, was titrated into the oil phase, gradually forming an oil-in-water emulsion. According to our findings, phase inversion happened at the 55-70% of the added water phase. Stabiliser type and concentration had great influence on the oil droplet size. However, all the emulsions produced presented instability phenomena. Thus, indicating that the energy offered to the system by mixing was not sufficient. (C) 2015 Elsevier B.V. All rights reserved.