Évaluation du vieillissement de quatre huiles végétales utilisées en friture par la méthode d’illumination structurée (SLIPI-1p)

The aging of oils poses a significant challenge to food safety. This study evaluates the impact of repeated use of four frying oils (palm oil, sunflower oil, soybean oil, and extra virgin olive oil) during chicken frying, using the Structured Laser Illumination Planar Imaging (SLIPI-1p) technique at 450 nm. This method, which involves spatially modulating the intensity of a laser sheet with a diffraction grating, enables precise degradation analysis by measuring extinction coefficients. Fifteen samples of each oil were analyzed at specific temperatures and wavelengths. Additionally, the physicochemical properties of these oils were characterized according to AOAC standards, allowing for the correlation of measured optical properties with established quality standards. Sunflower oil remained usable up to the 10th frying cycle (78 minutes, extinction < 0.439 ± 0.001 mm⁻¹), while soybean oil maintained quality up to the 9th frying cycle (71 minutes, extinction < 0.488 ± 0.001 mm⁻¹). Palm oil showed significant degradation after the 6th frying cycle (49 minutes, extinction > 0.570 ± 0.002 mm⁻¹). Extra virgin olive oil reached degradation thresholds after 100 minutes of use, approximately at the 13th frying cycle (extinction > 0.680 ± 0.002 mm⁻¹). This study reveals that extra virgin olive oil is the most resistant to degradation, whereas palm oil is particularly sensitive to degradation. The results provide recommended usage thresholds for each oil and highlight the effectiveness of laser sheet imaging as a promising tool for assessing the quality of cooking oils. Keywords: Oil aging; Frying; Food safety; SLIPI-1p; Extinction coefficients.