Changes in colour, lipid oxidation and fatty acid composition of pork loin chops as affected by the type of culinary frying fat

Abstract

The goal of this study was to determine how deep-fat frying in olive oil (OO), sunflower oil (SO), butter (BT) or pig lard (PLD) affected the colour, lipid oxidation, coloured products from Maillard reaction and fatty acid composition of intramuscular fat of fried pork loin chops. Instrumental colour significantly changed with frying and type of culinary fat. Frying pork loin chops caused a significant increase in lipid oxidation index, measured as TBA-RS, in all samples except for butter-fried pork loin chops. Differences in the absorbances at 420 nm of coloured material extracted with different solvents were significantly affected by the kind of culinary fat used for frying. Absorbances at 420 nm of methanol extracted coloured materials (ECM) were significantly higher in OO fried samples than in BT ones, while absorbances at 420 nm of acetone ECM were significantly higher in PLD loin chops than in samples fried in the two vegetable oils –OO and SO–. Frying significantly modified fatty acid profiles of neutral lipids (NL) and free fatty acids (FFA) fractions, and slightly altered polar lipids (PL). Regarding NL composition, fatty acid composition of the samples fried with PLD did not differ markedly from that of raw loin chops. However, C12:0, C14:0 and C16:0 fatty acids increased 11, 2.6 and 1.1-fold (11, 47 and 289 g kg −1, respectively) in pork loin chops fried in BT. In samples fried in OO, oleic acid (C18:1 n-9) increased 1.4-fold (591 g kg −1), while linoleic acid (C18:2 n-6) increased 3.8-fold (313 g kg −1) in samples fried in SO. FFA profiles also reflected fatty acid profile of culinary fat. Lauric acid and total saturated fatty acids percentages significantly increased in BT loin chops. Besides linoleic acid percentages significantly rose in samples fried in SO.