Improvement of functional properties of wheat germ oil using oleogelation

In this thesis, wheat germ oil (WGO) oleogels were produced using WGO at 3%, 7%, and 10% oleogelator concentrations and, the most suitable ratios in terms of structural properties were tried to be determined. Stable gels were obtained with 3% candelilla wax (CDW), 8% carnauba wax (CRW), and 6% rice bran wax (RBW), and the quality properties of the WGO oleogels were determined during storage at 4 and 20 °C for 3 months. WGO oleogels produced with CDW and RBW were found to have high oil binding capacity. The solid fat content (% SFC) of the oleogels measured at 20 and 35 °C increased depending on the oleogelator ratio. The crystallization and melting temperature and enthalpy of oleogels increased depending on the amount of wax added. It was determined that RBW oleogels had the lowest, and CDW oleogels had the highest crystallization temperature. X-ray crystallography (XRD) peaks around 4.10 and 3.70 Å showed that the oleogels were similar to the desired β´ polymorphic form as in spreadable margarine.The crystal formation times of the oleogels has been decreased with increasing wax ratio. By evaluating the FT-IR spectra of the samples, it was determined that no chemical interaction occurred between the oleogel components and the gel was formed by non-covalent interactions. Free fat acidity, peroxide, and p-anisidine numbers were increased depending on time and temperature during storage. Considering these properties, it was determined that CDW oleogel stored at 4 °C had the best oxidative stability. However, CRW-produced oleogels were found to be more successful in preventing the destruction of tocopherols and phytosterols. According to the results of the rheology analysis, it was determined that the storage modulus (G´) of CDW and RBW oleogels were higher than the loss modulus (G´´) and they have properties of the elastic gel. In this study, as a result of structuring WGO with oleogelation, an alternative product with low cost, high storage stability, viscous at room temperature, and no trans-fatty acid was successfully produced, and it was revealed that this method could be among the oil modification techniques. Keywords: Wheat germ oil, Candelila wax, Carnauba wax, Rice bran wax, Oleogel, Oxidative stability