The restriction to the use of synthetic antioxidants has fostered the research on natural antioxidants,
taking into account that the prolonged usage of these substances can harm seriously the human being provoking
degenerative diseases. In the present study, the antioxidant
effect of the ethanolic rosemary (Rosmarinus officinalis L.)
extract on the oxidative stability of edible vegetable oils
was investigated by means of the pressurized differential
scanning calorimetry (PDSC) and oven test techniques. The
rosemary extract, at the concentration of 2,000 mg kg-1, as
well as the synthetic antioxidant tert-butylhydroquinone
(TBHQ) at the concentrations of 100 and 200 mg kg-1
were added to samples of sunflower oil, corn oil, and soybean oil. The fatty acid profiles of the vegetable oils were
determined by gas chromatography–mass spectrometry
confirming the elevated contents of unsaturated fatty acids.
The thermogravimetric analysis showed that the rosemary
extract is stable at the frying temperature of the oils. The
results of the oxidative stability demonstrated that the extract of Rosmarinus officinalis displayed a more effective
protective action in the PDSC technique, when compared
with the synthetic antioxidant TBHQ, indicating that it is a
promising source of natural antioxidants for edible vegetable oils.