INFLUENCE OF DEEP-FAT FRYING PROCESS ON PHOSPHOLlPID MOLECULAR SPECIES COMPOSITION OF SARDINA PILCHARDUS FILLET

Introduction. Fish is an excellent source of essential nutrients such as essential amino acids, bioactive latty acids, minerals, vitamins, chitin and antioxidants. The nutritional benefit of fish lies, predominantly, in its lipid Iraction which is mainly composed of phospholipids (PL) and triacylglycerols (TAG) exceptionally rich of n-3 polyunsaturated latty acids (n-3 PUFA). Recently, fish PLs have attracted a great deal of attention as they are considered more efficient carriers of n-3 PUFA than fish TAG in terms of n-3 PUFA absorption in different tissues. In addition, fish PLs have also exhibited antitumoral and anti-inllammatory effects. Unfortunately, lish PLs are highly susceptible to lipid oxidation and to thermal damage due to excessive heating. The n-3 PUFA chains in PLs are the primary targets of oxidation which can take piace during cooking processes. Since most fish are consumed cooked, the nutritional value of the final cooked product is of major importance lor human health. Especially, the determination of the effects of frying (a very popular method utilized lor fish cooking) on the n-3 PUFA rich lipid fraction of fish will provide uselul inlormation to consumers and to lood industry to establish the fish quality. Purpose. This study was, therelore, conducted to determine the inlluence of deep fat frying process on PL composition of edible muscle (fillet) of Sardina pilchardus, a fish species commonly consumed in Mediterranean countries. Design/methodology. The effects of deep-fat frying performed using different culinary lats (extra virgin olive oil, conventional sunflower oil and high-oleic sunfiower oil) and different frying temperatures (160 and 180°C) on the phosphatidylethanolamine (PE) and phosphatidylcholine (PC) molecular species composition (the preponderant fish phospholipid classes) were investigated. For each frying test, ten fish fillets were introduced into a deep fryer (capacity 2 L), in a closed environment, lor 5 min. The oil temperature prior to start frying has been set to established value (160 or 180'C) and it was controlled by a specific digital thermometer. Each cooking procedure was done in triplicate. The PL molecular species composition was determined by high pressure liquid chromatography (HPLC) coupled with a second order mass spectrometer (MS-MS) with electronebulization interface (ESI). Findings. The deep-fat frying process caused significative changes on PE and PC molecular species composition of the fish fillet. However, these changes were not related to the nature of the culinary fat and to the frying temperature. In all cases, the deep fat frying process caused a significative increase of the proportion of the PE and PC species formed by the combination of palmitic and docohexanoic acids and a significative decrease of the percentage of the PE and PC species formed by two docohexanoic acid residues. Keywords: Deep fat frying, European pilchard, phosphatidylcholine, phosphatidylethanolamine