Structural, physicochemical and rheological characterization of safflower oil oleogels structured by glycerol monostearate and stearic acid

Abstract

Abstract

This study aimed to develop safflower oil oleogels using stearic acid (SA) and glycerol monostearate (GM) as oleogelators at 10, 13, and 16% (w/w) concentration and to evaluate their structural, thermal, rheological, and oxidative properties. Oil binding capacity (OBC) and hardness increased significantly with increasing oleogelator concentration. At 10% concentration, GM oleogels (GMO) exhibited 1.83% higher OBC and 29.55% greater hardness than SA oleogels (SAO), while at 16% concentration the differences increased to 3.04 and 49.18%, respectively, indicating stronger network formation in GMO. Microscopic analysis revealed fine needlelike and spherical crystals in GMO, whereas SAO displayed larger fibrous crystals. All samples showed shear-thinning behavior (n 0.90). Frequency sweep tests confirmed dominant solid-like behavior, with increased storage and loss moduli at higher concentrations. Recovery rate improved with increasing oleogelator concentration, with GMO at 16% showed the highest recovery (26.17%). Thermal analysis indicated improved thermal stability with increasing concentration, while X-ray diffraction revealed β and β′ polymorphs. FTIR analysis suggested hydrogen bonding and van der Waals interactions. Higher oxidative stability was noted for GMO compared to SAO. The study found that GM produced stronger, more elastic, thermally, and oxidatively stable oleogels.