Emulsion Stability and Vegetable Oil Identification and Adulteration

The emulsion stability of nitromethane/vegetable oil is use for the rapid identification and quality control of vegetable oils. Using a volume ratio of nitromethane to vegetable oil of 3:7, the emulsion stability of nitromethane/vegetable oil increases in the following order: nitromethane/palm oil, nitromethane/peat-nut oil, nitromethane/corn oil, nitromethane/soybean oil and nitromethane/sesame oil. The nature of vegetable oil influences the emulsion stability. Falsification of sesame oil with 10% corn oil or any cheaper vegetable oil decreases significantly the stability of nitromethane/sesame oil emulsion. These results indicate that the method could be used for rapid identification and quality control of vegetable oils.