From an oil with “antifoaming” properties to stabilization for foam: A novel approach for establishing a long-term stable foam system

Abstract

Can a foam be synergistically stabilized by particles and oil? Sure it can. A new strategy for preparing “capillary foam” based on whey protein isolate particles (WPs) was designed by co-stabilization with coconut oil (CO) to improve foam stability. Unique aspect of the “capillary foam” presented here was the protein particle-facilitated diffusion of the minority oil around the bubble. The foamability and foam stability were evaluated based on size, ζ-potential, and surface wettability of particles, as well as different oil phase concentrations. Foam stability was significantly improved in the presence of a minor amount of CO (1%, v/v). The size and hydrophobicity of the particles become important factors in determining the stability of the “capillary foam”. The oil/water contact angle (θo/w) of the particles was close to 90° at pH 5.0, which makes it easier for particles to adsorb at the oil/water interface compared to the air/water interface, thus facilitating the formation of the special structure of the “capillary foam” with high stability. The distribution of the oil phase around the bubble surface raised with the increase of oil phase mass fraction, although the stability decreases slightly. This strategy provides useful tips and achieves a fundamental breakthrough, which means that the new idea of “capillary foam” is promised to furnish a new solution to the challenge of food foam stability.