Determination of the extent of rancidity of soybean oil by gas chromatography compared with peroxide value

The development of rancidity in soybean oil has been studied by gas chromatography (GC), peroxide value (PV) and sensory evaluation. The GC method has been adapted from previous methodology and another type of column packing has been used for the purpose. The GC peaks have been treated as one whole group, and and oxidation value (OV) has been computed by means of an internal standard (n-octanol). The OV’ have been correlated with the PV’s. The flavor of soybean oil and a blend of 50% soybean oil and 50% hydrogenated soybean oil, both kept at 60 C for varying lengths of time, was evaluated by a panel and the results have been presented in a new graphical form. A relationship between the OV and the flavor of the fat has been demonstrated. The merits of the method are discussed.