Effects of the type of frying with culinary fat and refrigerated storage on lipid oxidation and colour of fried pork loin chops

The effects of different types of culinary frying fats and oils (olive oil -OO-, sunflower oil -SO-, butter -BT- and pig lard -PL-) were studied in relation to lipid oxidation and instrumental colour in fried pork loin chops during 10 days of refrigerated storage. At day 0, pork loin chops fried in butter showed significantly lower values of TBARS (0.37 mg MDA/kg, p < 0.05) than pork loin chops fried in the oils/fats (OO = 0.57 mg MDA/kg, SO = 0.55 mg MDA/kg, PL = 0.61 mg MDA/kg, p < 0.65). After 10 days of refrigerated storage, the highest TBARS values were found in BT (2.06 mg MDA/kg), while the lowest one was found in OO (0.91 mg MDA/kg.). At day 10, SO and PL showed intermediate values for BT and 00 (SO = 1.71 mg MDA/kg, PL = 1.74 mg MDA/kg, p < 0.05). Pork loin chops showed a progressive discolouration during 10 days of refrigerated storage. Parameters of instrumental colour values (L*, a*, b*, c*) tended to decrease during the storage period, while h(o) values tended to increase. High negative correlation was observed between methanol-extracted coloured materials and TBARS values at 10 days (Pearson's Correlation = -0.783, p < 0.01), which is indicative of a possible antioxidant activity of Maillard reaction products (MRPs). Lipid oxidation and colour of fried and refrigerated meat were possibly influenced by changes in fatty acid profiles of meat, incorporation of natural antioxidants (proceeding from vegetable oils) and antioxidant activity of MRPs formed during the frying period. (C) 2004 Elsevier Ltd. All rights reserved.