Development of lecithin and stearic acid based oleogels and oleogel emulsions for edible semisolid applications

The objective of this study was to characterize a novel soy lecithin (SL) based oleogel (LOG) and oleogel emulsion (LOGE) prepared with different proportions of stearic acid (SA). Oleogels were developed with 1 wt% of water, and two gelator concentrations (20 wt% and 30 wt%) with SL:SA ratios (0:10, 3:7, 5:5, 7:3, 10:0). The same SL:SA proportions were used to prepare LOGE with 10 wt% and 20 wt% of water. Small (SAXD) and wide (WAXD) angle x-ray diffraction studies and polarized light microscopy were conducted to determine the nano- and microstructure of the samples. The hardness of the samples was analyzed using a texture analyzer and the thermal properties with a differential scanning calorimeter. The results indicate that LOG were primarily formed through the entanglement of bundles of reverse worm-like micelles of SL; however, LOGE were structured mainly through SA crystals that interacted in a synergistic fashion with the SL reverse micelles network to stabilize the three dimensional network. The hardness of the LOG and LOGE increased with an increase in SA, however, in samples containing both SL and SA, LOGE were harder than LOG, demonstrating that the oleogelators have a synergistic effect. The novel hybrid LOG and LOGE formulated with SA can be used as a more stable alternative to SL oleogels particularly when the objective is to achieve semi-solid characteristics.