Improvement of vegetable oils quality in frying conditions by adding rosemary extract

[Display omitted] •Rosemary extract prevents the oils oxidation during heating.•Lower acidity and peroxide value until 30h of heating in a formulated oil.•Rosemary extract enhance fried potatoes quality until the fifteenth frying.•The formulated oil showed a best quality compared to the control oil. The effect of rosemary extract (Rosemarinus officinalis L.), a natural antioxidant, on stability of frying oil during heat treatment and on sensorial quality of fried potato was studied. A mixture of soybean and sunflower oils in an equal proportions and containing 0.08% of rosemary extract was evaluated for thermo-oxidation at 180°C for 30h. This evaluation was carried out comparatively to an oil mixture without antioxidant. Results showed a significant difference (p