Degradative Quality and Emission Implications of Repeatedly Heated Cooking Oil in Indoor Environment

Abstract

The study examined the effects of heating the same batch of oil for multiple frying cycles on the pollutants that are released into the air and the degradation of the oil’s quality. Principal component analysis under the physicochemical metrics framework was used to study singular and interaction effects of three oil brands, frying duration and temperature. Physicochemical parameters showed that peanut oil has high unsaponifiable matters, the refractive index and kinetic viscosity prior to frying. Specific gravity and acid value were significantly lower for soya bean oil after frying with values 0.42 ± 0.02 and 0.20 ± 0.01 in order. The values of 4.09 ± 0.04 meqO2/kg and 114.96 ± 0.23 mgKOH/g obtained for peroxide value and saponification value respectively were significant for olive oil during post frying analysis. The emission values were in the ranges 98.17 ± 0.15 (x103)-573.20 ± 0.20 (x103),11.0 mg/m3 at 60 °C-34.0 mg/m3 at 140 °C, 0.051 mg/m3 at 60 °C-0.088 mg/m3 release at 140 °C, 59.0 μg/m3 at 80 °C-72.0 μg/m3 at 120 °C, and 0.057 mg/m3 at 60 °C-0.078 mg/m3 at 140 °C respectively for PAH, CO, NO2, SPM, SO2. Temperature had a significant impact on the rates of emissions when combined with time. The inherent patterns and trends within the data matrix suggest that oil brand quality was the most significant factor influencing the clustering of observations. Therefore, heating cooking oils to moderate temperatures and using a large volume of the oil could result in minimal rates of evaporation and pollutants emission