Development of glucose fatty acid esters as novel oleogelators: Enzymatic synthesis, structure-activity relationship,...

Developing efficient food-grade oleogelators remains challenging for the replacement of traditional solid fats. Given the biocompatible nature of sugar esters, a homologous series of glucose mono-esters with acyl chain lengths ranging from C10 to C18 was enzymatically synthesized and evaluated for their ability to structure plant oils. The results obtained indicated that esters incorporating C14-C18 side chains were the most effective oleogelators, being capable of structuring olive oil at concentrations as low as 4 wt%. Increases in acyl chain length or oleogelator concentration enhanced oil-binding capacity and mechanical strength. Glucose monostearate (G-C18) exhibited the best performance, affording an oil-binding capacity of up to 88.86% and storage moduli that were approximately 2- and 5-fold higher than those of the shorter-chain systems. Further analyses suggest that these glucose mono-esters self-assembled through the combined effects of hydrogen bonding associated with headgroups and van der Waals interactions between the alkyl chains, forming a β-like crystalline network. Rheological studies revealed that the resulting oleogels displayed solid-like viscoelastic behavior, shear-thinning characteristics and good resistance to external disturbance, while their nonlinear responses were modulated by both acyl chain length and oleogelator concentration. Glucose monostearate was further used to structure peanut, corn, sunflower seed, and flaxseed oils, with the derived oleogels showing broadly comparable mechanical strengths and disturbance resistance but oil-dependent thixotropic recovery rates ranging from 1.59% to 52.97%. As such, this study establishes systematic structure-activity relationships of glucose mono-esters, highlighting their significant potential as food-compatible oleogelators for the development of solid fat replacers.