Design and fabrication of structured oil (oleogel) -zero Trans fatty acid- using canola oil and evaluation of its physicochemical and rheological properties

Abstract

ackground: In recent years, consumer awareness of the importance of diet to human health is increasing. Due to the dverse effects of high intake of saturated fatty acids and especially unsaturated trans fatty acids on human health, including cardiovascular disease, type 2 diabetes and metabolic syndromes, new rules have been established to limit the consumption of saturated fatty acids and ban the use of acids Unsaturated trans fat is introduced by the legislative committees. Many efforts have been made to find suitable substitutes for saturated and trans fatty acids in order to create the proper structure and texture in food products. Recently, a new technique called oleogel or organogel has been considered. In this case, the liquid oil is trapped inside a thermally-reversible 3D gel network using gelling components (oleogelator) and exhibits solid-like properties. The purpose of this study was to produce soybean oil oleogels using a combination of two ethyl cellulose and behenic acid oleogelators and to investigate their physicochemical and rheological properties. Materials and Methods: Ethyl cellulose and Behenic acid (in the range of 0-6 wt%) Were added to pure soybean oil and heated to a high temperature ~ 150 °C for 20-30 minutes at constant rpm using a heater equipped with a magnetic stirrer. When the powders were completely dissolved and clear solutions were obtained, the heating was stopped and then cooled with a low cooling rate up to about 22 ° C. They were then stored in the refrigerator for at least 20 h at 3 °C. After this time, slip melting point, solid fat content and peroxide content were determined. Rheological tests were performed using rheometer and thermal stability using differential scanning calorimetry analysis. Polarized light microscopy and X-ray diffraction were used to observe the morphology and size of the crystals. Possible chemical interactions between the compounds were also performed using Fourier Transform Infrared Spectroscopy (FTIR). Results: Oleogels were produced by combining two ethyl cellulose and ethyl cellulose oleogelators (0-6 wt%). EC-based oleogel (6 wt%) showed high melting temperature (above 85°C) and complete elastic behavior (G'~1000 mPa > G") with low oil-binding capacity (oil loss > 30 %), and no thermo-responsive behavior (in the temperature range of 25-80°C). The combination of BA and EC improved the rheological properties and oil binding capacity of oleogels at specific ratios (EC:BA 2:4 and 1:5 wt%). High strength (G' >1000 mPa) was observed in these formulations which was higher than EC oleogel (6 wt%). Good thermo-responsive and viscoelastic behavior in the range of 45-60°C and low loss of oil (< 0.2 %) were observed in these oleogel formulations. Polarized light microscopy images and XRD results showed the presence of crystals and high proportion of crystalline regions in the mentioned formulations. There were no significant differences among solid fat content (SFC) of EC contained oleogels. In fact, both the weakest (EC:BA 3:3 wt%) and the strongest (EC:BA 2:4 and 1:5 wt%) rheologically had high solid fat content. Conclusion: As a general conclusion, it is possible to produce food grade stable oleogels using soybean oil and the combination of ethyl cellulose and Behenic acid. Such oleogels appear to have good potential foruse in food product formulation to reduce product quality defects as well as a healthy replacement for different types of semi-hydrogenated oils in various products