Partial coalescence in emulsions: The impact of solid fat content and fatty acid composition

Abstract

Oil‐in‐water emulsions were made with five different triglyceride fats ranging from completely liquid oil to solid. Regardless of the type of dispersed fat, all emulsions were non‐aggregated and low viscous when stabilized only by caseinate. Presence of lactic acid ester of monoglyceride (LACTEM) and unsaturated monoglyceride (GMU) caused solidification of emulsions made with fat with intermediate solid fat content (SFC), due to fat globule aggregation. The hardest and most compact fat globule network was obtained for emulsions based on hydrogenated palm kernel oil (HPKO). Although palm kernel oil (PKO) and palm oil (PO) resembled HPKO in terms of fatty acid (FA) composition and SFC, a lower strength of the fat globule network was obtained for emulsions based on PKO and PO. The dispersed fat phase should have intermediate SFC (simultaneous presence of liquid and solid fat) in order to induce fat globule aggregation in emulsions. This was demonstrated by emulsions made with either rapeseed oil (RO) and fully hydrogenated palm oil (FHPO), which remained stable and pourable despite the presence of LACTEM and GMU.Practical applications: This study emphasizes the important role of fat on the texture of O/W‐emulsions. This knowledge is vital for the industry in order to control or avoid fat globule aggregation. For manufacturers striving for partial coalescence of emulsions to occur, it is necessary to use low‐molecular‐weight emulsifiers and fat with intermediate solid fat content.Emulsions stabilized by sodium caseinate remained stable and non‐aggregated independent of the type of dispersed fat. When emulsions were stabilized by a combination of sodium caseinate, LACTEM, and GMU, partial coalescence occurred for fat globules with intermediate solid fat content while globules of either solid fat or liquid oil remained stable.