Developing ribose fatty acid mono-esters as novel oleogelators with tailored colloidal properties: enzymatic synthesis, structure-activity relationships and mechanistic insights.

HYPOTHESIS: Progress on the development of novel oleogelators that effectively combine green attributes with superior colloidal properties remains limited. Since sugar mono-esters are recognized as green amphiphiles that possess intrinsic self-assembly properties, ribose-based variants are expected to serve as highly efficient oleogelators and so addressing existing deficiencies.

EXPERIMENTS: An homologous series of ribose fatty acid mono-esters (C8-C18) was prepared enzymatically and deployed as oleogelators in vegetable oil matrices derived from sunflower seeds, peanuts, camellias, olives and corn. The gelation mechanisms and structure-activity relationships were systematically investigated using a combination of rheological, X-ray diffraction and infrared spectroscopic techniques.

FINDINGS: Ribose mono-esters have been identified as novel oleogelators that act at concentrations as low as 2 wt% and so significantly outperforming their mainstream counterparts. The associated colloidal characteristics can be effectively tailored by modulating the length of the fatty acid residue that shifts the dominant self-assembly force from hydrogen bonding in the shorter homologs to van der Waals interactions in the longer ones. The crystalline networks formed using longer-chain esters exhibited an approximately 30-fold increase in mechanical strength and a ca. one- to two-fold enhancement in oil-binding capacity over their shorter counterparts. However, this structural enhancement compromised deformability, leading to a ca. three-fold reduction in thixotropic recovery rates. The capacity of the mono-esters to form β-polymorph crystalline networks was validated across all tested oil matrices. This study details both the gelation mechanisms and structure-activity relationships, highlighting the design principles for establishing ribose esters as next-generation oleogelators.