Erythritol-Based Medium-Chain Sugar Amphiphile: Synthesis and Gelling Capability in Edible Oils

The production of organogels from vegetable oils requires low-molecular-weight gelators. Herein, a novel small-molecule sugar ester gelator is synthesized from erythritol and octanoic acid. The purified reaction product is identified as erythritol 1,6-dioctanoate by high performance liquid chromatography (HPLC) with evaporative light-scattering detection and nuclear magnetic resonance (NMR). This low-molecular-weight erythritol ester exhibits self-assembly behavior in vegetable oils with a minimum gelation concentration of 4 wt%. Microscopy reveals needle-like crystals that became slender as the gelator concentration increases. X-Ray Diffraction (XRD) analyses indicate that the organogels are semicrystalline with both crystalline and amorphous domains. Fourier Transform Infrared (FTIR) spectroscopy reveals that the gel structure is maintained by non-hydrogen-bonding interactions. Furthermore, rheological tests show that the mechanical strength of the gel is poor, but as the gelator concentration is increased, the mechanical strength and hardness of the gel also increases. Thus, this erythritol ester effectively promotes the gelation of edible vegetable oils and increases the variety of available organogelators. Practical Applications: The synthesized erythritol ester is successfully applied as a gelator to produce organogels from a variety of vegetable oils, and are expected to advance the development of effective organogelators for edible oils.