Squalene in oils and fats from domestic and commercial fryings of potatoes

Squalene was determined in commercial frying oils and fats (sunflower oil, cottonseed oil, corn oil, soybean oil, palm kernel oil, palm oil, vegetable shortening oil, and cooking fats) sampled during deep-frying of potatoes from 21 restaurants in Athens, Greece, and in domestic frying oils [virgin olive oil (VOO), vegetable shortening and sunflower oil] used during the domestic pan-frying and deep-frying of potatoes. The analyses were carried out after cold saponification of the oils followed by gas chromatography-mass spectrometry of the hexane extract. Quantification was carried out by reference curve, using standard squalene solutions. Fresh vegetable oils and fats were found to contain small amounts of squalene (10.2-49.3 mg/100 g oil or fat), with the exception of fresh VOO, which contained 454 mg/100 g. The squalene content of the frying oils was reduced during frying, its lower concentration found in cooked fats (5.9 mg/100 g fat) and its higher in fried VOO (428 mg/100 g oil) after the first frying session. Squalene appeared to be rather stable during frying. Its retention in used restaurant seed oils and fats remained over 50% even after 30 h of frying while a high recovery of 84-96% was observed during the domestic deep-frying of potatoes in VOO. It seems that by using VOO as frying medium a considerable amount of squalene is absorbed by the fried potatoes, thus becoming part of our diet.