Shedding Light on Insulation: Probing the Varied Effects of Illumination and Storage Temperatures on Vegetable Oil Quality

This study conducts experimental investigations into the quality of three types of vegetable oils: commercial soybean-derived vegetable oil, refined, bleached, and deodorized coconut oil (RBD coconut oil), and virgin coconut oil (VCO). These oils were subjected to exposure under different lighting conditions (direct sunlight or fluorescent light) and elevated storage temperatures over a 6-month period. Various parameters, including color number (ASTM D1500), kinematic viscosity at 40°C (ASTM D445), acidity (IEC 62021), peroxide value (AOCS Method Cd 8-53), refractive index using an Abbe refractometer, tanδ (IEC 60247), and power frequency AC breakdown voltage (ASTM D1816), were measured to assess the oils’ quality. The findings reveal that storing oils for 6 months in dark conditions or under fluorescent light has a negligible impact on the quality of insulating oils. However, exposure to daylight conditions or storage at 60°C significantly influences their insulating properties. Notably, virgin coconut oil exhibits high resistance to photo-oxidation but deteriorates rapidly due to the heating effect of storage, whereas RBD coconut oil is the least affected by storage temperature. In summary, the results indicate that RBD coconut oil better preserves its insulating properties than virgin coconut oil under varying conditions of light exposure or storage temperature.