Oil Mobility in Hazelnut Oil-Based Oleogels Investigated by NMR

The migration of triacyl glycerides such as hazelnut oil leads to quality losses in various foods (e.g., fat bloom formation on chocolate, also named "fat ripening"). Oleogelation, i.e., dispersion of oils in a solid matrix of gelators, is thought to immobilize oils and consequently to hinder oil migration, leading to questions about the translational, but also intramolecular mobility of triacyl glycerides in the oleogels. In addition to translational mobility measured by diffusion-NMR, the molecule-intrinsic dynamics is reflected in NMR-relaxation. In this study, transverse relaxation and diffusion were explored to obtain insight into the condition of the oils in the disperse materials. Oleogels based on sunflower seed wax are compared to oleogels based on mono- and diglycerides. In both types of oleogels NMR-measures depend on composition as well as on temperature. Studying both dimensions, concentration and temperature, reveals the restricted mobility of oil molecules in the oleogels.