Behaviour of tocopherols, heavy metals and stability of some vegetable oils from Egypt and Iraq during refining

Abstract

AbstractSamples of crude, neutralized; bleached and deodorized cotton seed oil (Egypt), safflower oil (Iraq) and sunflower oil (Iraq) were analyzed for their total tocopherol and their contents of iron and copper, The stability of oils under investigation was measured by the Active Oxygen Method. The crude oils investigated contained from 1.22 to 1.87 ppm of iron and from 0.083 to 0.956 ppm of copper. These values for completely refined oils used were found to range from 0.626 to 1.01 ppm for iron and from 0.051 to 0.576 ppm for copper. The total tocopherol decreased from a range of 77.8 to 113 mg/100 g oils in crude oils to a range of 62.8 to 91.3 mg/100 g oil when the crude oils were completely refined. Studies on oils differing in the degree of refining used in this work evidence that neutralization and bleaching cause great decrease in total tocopherol, iron and copper. Meanwhile, deodorization had no pronounced effect on iron and copper, whereas its effect on total tocopherol was slight. The stability of the vegetable oils investigated decreased markedly during refining.