Enhanced foamability and stability of aqueous foams through novel pickering fat globules formulated with solid lipid particles

Abstract

Pickering fat globules (PFGs), known for their remarkable stability via the Pickering effect, eco-friendliness, and ability to carry hydrophobic flavors and nutrients, play a pivotal role in the advancement of food foam systems. This study investigates highly unsaturated and exceptionally stable aqueous foams stabilized by PFGs with interfacial activity. These PFGs are derived from two types of solid lipid particles (SLPs): fully hydrogenated soybean oil with sodium caseinate (FHSO-SC-SLPs-PFGs) and glyceryl stearate citrate (GSC-SLPs-PFGs), which were formulated with varying SLPs concentrations (0.5 wt%, 2.5 wt% and 5 wt%) while coating 10 wt% and 20 wt% oil droplets. Remarkably, 0.5 wt% SLPs could accommodate up to 20 wt% of low-melting-point liquid oil, enhancing the unsaturation of PFGs. GSC-SLPs-PFGs generated foams with overrun values reaching up to 235%, exhibiting stability for at least 40 days. In contrast, foams derived from FHSO-SC-SLPs-PFGs, with the highest overrun value of 145%, remained stable for only 2 h. Compared with FHSO-SC-SLPs-PFGs, GSC-SLPs-PFGs exhibited superior foaming performance and stability attributed to their properties such as smaller particle size, enhanced hydrophilicity, higher apparent viscosity, increased surface potential, and superior surface tension reduction. Furthermore, increasing the concentration of SLPs and/or reducing the oil phase can also improve the properties of SLPs-PFGs, resulting in greater foamability and foam stability. Surface dynamic adsorption, interfacial shear rheology, and microstructural observations revealed robust adsorption of all SLPs-PFGs at the air-liquid interface, indicative of pronounced Pickering stabilization, with GSC-SLPs-PFGs also exhibited three-dimensional network structure. These SLPs-PFGs stabilized foams presented heightened stability and reduced saturated fat content, paving the way for novel and healthier foam-based food products.