Quality Evaluation of Frying Oils under the Conditions of Western Fast Food Restaurants Based on Principal Component Analysis

In order to explore the quality of frying oils under the condition of western fast food restaurants and establish a quality evaluation system of frying oils, 11 physical and chemical quality indexes of five common frying oils (soybean oil, rapeseed oil, sunflower oil, palm oil and rice bran oil) during simulating the conditions of western fast food restaurants for frying French fries at 170 ℃ for 7 days were detected. At the same time, the frying performance of five frying oils was comprehensively evaluated by principal component analysis (PCA), and the quality evaluation model of frying oils was established. The results showed that acid value, total polar component, carbonyl group value, anisidine value, total oxidation value and color increased significantly (P<0.05) after the frying period, while the total vitamin E content and oxidative stability index decreased significantly (P<0.05). Correlation analysis indicated that anisidine value, total oxidation value and carbonyl group value were significantly positively correlated with each other (r=0.877~0.997, P<0.05), while color was significantly positively related to acid value (r=0.822, P<0.01). Iodine value was significantly negatively correlated to oxidative stability index (r=−0.846, P<0.01), while significantly positively related to the ratio of C18:2/C16:0 (r=0.833, P<0.01). Three comprehensive indexes were extracted by PCA, with an accumulative contribution rate of 84.115%, reflecting most of the information of the original indexes, and the comprehensive quality evaluation model of frying oils was established as F=0.405F₁+0.295F₂+0.141F₃. According to the model, palm oil had the highest comprehensive score, indicating the best frying performance among the five frying oils. These findings can provide a reference for the quality evaluation and quality control of frying oil under the conditions of western fast food restaurants.