A simple emulsion for measuring fat taste sensitivity

Fat taste detection threshold (DT) is a marker of gustatory sensitivity to fatty acid (FA). A higher DT may be associated with greater fat and energy intakes and body mass. FA emulsions with varying compositions have been used to measure fat taste DT, but the lack of consistency and complex formulations are limitations of the methodology. We aimed to develop a stable FA emulsion with minimal additives (Study 1) and determine its agreement with a previously validated emulsion to measure fat taste DT, and its associations with anthropometry and proximal dietary intake (Study 2). In Study 1, three oleic acid (OA) emulsions (surfactant-free, lecithin-based, and gum-and-milk-based) were formulated from 0.4 to 50 mM, and their stability was measured over 7 days. The lecithin-based emulsion was the most stable at all durations and concentrations. The lecithin-based and gum-and-milk-based emulsions from Study 1were used in Study 2 to determine fat taste DT using an ascending-series 3-alternative forced choice method in 35 healthy Australian adults. Automated self-administered 24-h dietary intake and anthropometry were measured. Logistic regression models were fitted to calculate DTs; intraclass correlations (ICC) between DTs for each emulsion were estimated; and associations between DTs, dietary intake, and anthropometry were estimated using mixed models. DTs for each emulsion had good agreement (ICC = 0.696, p < 0.001). Both DTs were associated with waist-hip ratio (β = 0.03 for both), but only the lecithin-based emulsion DT was associated with energy (β = 744), fat (β = 2.6), and protein (β = 12.8) intakes. The lecithin-based emulsion proved to be a suitable alternative to the current FA emulsions to measure fat taste DT. Predictive modelling suggests that future measures of DT using the lecithin-based emulsion should test OA concentrations ranging from 0.53 to 43 mM.