Optimization and characterization of soybean oil-carnauba wax oleogel

Abstract

Oleogel formulation based on soybean oil – carnauba wax was optimized using response surface methodology to achieve the desired oil binding capacity (OBC), textural and rheological attributes. Highly significant factors affecting the preparation of oleogel were the heating temperature and wax concentration. The best formulation was obtained at - carnauba wax: 8%, heating temperature: 92 °C, and storage temperature: 10.7 °C. The optimized oleogel had a high OBC (97.31%) and showed a shear-thinning behavior (n < 1). Amplitude sweep revealed that at low strain values the gel is stable and cross-over point occurred at 361.4 ± 0.6 Pa with a strain of 12.01 ± 0.2%. The frequency sweep showed that oleogel had a very low-frequency dependence. The oleogel FTIR spectra showed that the gel network formed via physical entanglements without any changes in its chemical properties. The spectrum of oil and oleogels exhibited specific peaks at 2922, 2855, 1743, 1460, 1159, and 718 cm-1. According to the DSC results, the oleogel had a single, broad melting peak with a melting temperature of about 75 °C. The smoke point of the oleogel (283 ± 2 °C) was higher than oil (232 ± 0.4 °C), which indicates its suitability as a frying medium.