Determination of fatty acid oxidation in different types of edible oil during storage

Abstract

In this report, fatty acid oxidation was determined by analyzing different edible oil samples for the peroxide value parameter. In the quantification of peroxide value in olive and sun flower oils, the rapid spectrophotometric method was used and iron (111) calibration standards were used as reference standards to compare the absorbance of edible oils with the concentration of iron (111) in the sample using a UV- Visible spectrophotometer. The peroxide value was determined using the absorbance of the sample as indicated in the method in duplicate. This method was used for both autoxidation and photoxidation. It was noticed that peroxide formation was higher in photoxidation as compared to autoxidation. For the olive oil sample, the value of the peroxide parameter exceeded 10 meq/kg only after 12 days for the daylight exposed sunflower oil. For the samples kept to dark the peroxide value set a small amount of variations relatively to the daylight exposed samples and the sunflower oil, the value of the peroxide parameter exceeded 10 meq/kg only after 11days for the daylight exposed sunflower oil and for the samples kept to dark the peroxide value set a small amount of variations relatively to the daylight exposed samples. A kinetic model as per APPENDIX was simulated using MATLAB software and a script of the model was developed. The results from simulation peroxide value with time at different storage temperatures as shown in subplots 1 and 2 represented as Figure 0-4 and Figure 0-5 . It was realized that peroxide value increases with temperature. The model was validated using an exponential fit, a correlation of 0.6759 was obtained with experimental data for olive oil. A correlation of 0.9945 was obtained using experimental data using the same fit for sunflower oil