The use of chitosan aerogels as an adsorbent for the regeneretion of frying oil

Delice, Feyza Nur
One of the most commonly used food preparation methods is frying. The improvement of the quality of used frying oil (UFO) is important because the reuse of regenerated oil could provide significant savings to the food industry. This study aimed to enhance the quality of used sunflower oil by using chitosan aerogels (CA), which can be considered as novel adsorbents with an increased surface area. Aerogels are novel nanostructured materials with high porosity and large surface area. In this study, CA were produced by drying the 2% (w/v) chitosan gels using supercritical CO2 (SC-CO2) drying. In the study, 32 consecutive deep-fat frying were performed using potato slices in sunflower oil at 180 ± 5 °C. The effect of the adsorbent concentration (0.5, 1, and 2% (w/w)) and different adsorption temperatures (90, 135, and 180 °C) were studied by examining the UFO before and after the adsorption treatments. The physicochemical properties of the oil were analyzed by determining free fatty acid (FFA) content, total polar compounds (TPC), smoke point, p-anisidine value (p-AnV), and color (CIE L, a*, b*). Moreover, the structural changes of aerogels after the adsorption process were investigated by Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). FFA results showed that CA could reduce the % FFA values considerably due to the ionic interaction between CA and FFA. The results of TPC showed that CA could not adsorb the polar molecules formed during frying effectively. Yet, the smoke point increased significantly (p<0.05) after CA treatment, which means it effectively adsorbed nonpolar and low molecular weight molecules causing smoke. The p-Anisidine value was compensated with CA.
Citation Formats
F. N. Delice, “The use of chitosan aerogels as an adsorbent for the regeneretion of frying oil,” M.S. - Master of Science, Middle East Technical University, 2023.