Stability study of edible sunflower oil colored with chlorophyll pigments and with addition of oregano oleoresin (Origanum vulgare L.) during the storage in darkness

Abstract

Sunflower (Helianthus annuus L.) oil was coloured with pigments extracted from green leaves. Different amounts (0, 200, 400, 600, and 800 ppm) of oleoresin extracted from oregano (Origanum vulgare L.) as antioxidant, were added to the coloured oil. As controls, coloured oil without oleoresin (A.C.) and pure oil (A.P.) were used. The samples were stored at room temperature (10-20 ºC) in the dark for up to six months. During this time the oxidation of oleic acid, linoleic acid, peroxides index and the chlorophyll pigments were analized and the colour of the oil was determined. During the first month, only the ratio of chlorophyll to pheophytin changed, whereas all the other parameters stayed constant, independently to the amount of antioxidant added. Since among the treatments A.C. and A.P. not significant differences (p >0,05) were found, for oleic and linoleic methyl ester acids and peroxides index, it can be concluded that the edible, coloured sunflower oil shows an equivalent stability to the pure oil, when stored at darkness for three or six month. There was not observed an evident antioxidant action with the added oregano oleorresin to the coloured oil.