Elucidation of the Effect of Monoglycerides on Aroma Release at the Low-Fat Spread Interface

This study aimed to elucidate the mechanism of flavor release at the W/O emulsion interface for low-fat spreads. Flavor release from W/O emulsion samples was compared by GC/MS analysis, using two types of monoglycerides with different degrees of unsaturation. Saturated monoglycerides at the oil–water interface in W/O emulsion samples decreased fatty acid release at an adsorption temperature of 30°C. X-ray diffraction revealed that a two-layered lamellar phase formed by saturated monoglycerides at the oil–water interface at 30°C, and fatty acids were trapped in this bilayer lamellar phase, which probably reduced their release into the gas phase. Furthermore, as the temperature rose, the two-layered lamellar phase of saturated monoglycerides collapsed, and the difference in fatty acid release between the two W/O emulsion samples, with different degrees of unsaturation, became smaller. When only unsaturated monoglycerides were present at the oil–water interface, the two-layered lamellar phase was not formed; therefore, the amount of fatty acids trapped in an interface with unsaturated monoglycerides was smaller than that with saturated monoglycerides.  It is thought that the flavor retention structure of the interface formed by saturated monoglycerides greatly affected fatty acid release from low-fat spreads. Our findings will be useful in controlling flavor release in the production of low-fat spreads.