A comparative study of analytical methods for evaluation of soybean oil quality

This study is focused on the improvement of soybean oil stability by addition of additives and blending with more stable oils. The methods for evaluation of oil deterioration include changes in dielectric constant (DC), total polar (TP) compounds, refractive index (RF), fritest (FT), acid value (AV), iodine value (IV), anisidine value (AnV), carbonyl value (COV), viscosity and color. Statistically significant correlations were obtained between changes in DC and increase in the TP compounds, RF, FT, AV, AnV, COV and the decrease in the IV, respectively. Food oil sensor reading of 4 as a measure of changes in DC of oil has been suggested as the criterion of low oil quality. Consequently, the cut‐off level for straight and blended soybean oils were thereby identified by using the above parameters.