Elucidation of the effect of monoglycerides on aroma release at the low-fat spread interface

This study aims to elucidate the mechanism of aroma release at the water-in-oil (W/O) emulsion interface in low-fat spreads, which has not been previously studied. Two types of W/O emulsion samples were prepared: one using only oleic acid monoglyceride (OMAG), referred to as UMG, and the other using OMAG + palmitic acid monoglyceride (PMAG), referred to as USMG. To evaluate the effect of differences in the unsaturation degree of monoglycerides on aroma release, 35 types of aroma component reagents were added to these samples, and aroma component analysis was performed using solid-phase microextraction (SPME) combined with gas chromatography (GC) coupled with mass spectrometry (MS). Findings revealed that at an adsorption temperature of 30°C, lower amounts of fatty acids were released from USMG than from UMG. X-ray diffraction analysis of the USMG interface revealed a two-layered lamellar phase of PMAG (length, 44.5 Å). Thus, the decrease in fatty acids released from USMG at 30°C was attributed to fatty acid retention in the two-layered lamellar phase. This study is the first to demonstrate a relationship between the interfacial structure of W/O emulsion and the release of aroma components, and it provides valuable insights for improving the quality of food spreads. • Aroma release from water-in-oil (W/O) emulsion was compared between samples by GC/MS. • W/O samples compared included monoglycerides with different degrees of unsaturation. • Fatty acid release at 30°C was reduced in W/O samples with saturated monoglycerides. • A two-layered lamellar phase formed by saturated monoglycerides was revealed by XRD. • Fatty acids were trapped in this bilayer lamellar phase, which reduced their release.