Seasonal characterization of lipid component in sheep milk from different areas of Marche region

This study was conducted on sheep milk to determine the fat composition in flocks of different breeds (Suffolk, Fabrianese, Sopravvissana, Sarda) living in Marche region areas (central Italy). Samples were collected from December to July and the fatty acid profile, cholesterol content, lipid peroxidation status and antioxidant activity of lipid extracts were analyzed. The results show high levels of saturated fatty acids (SAT) for each period of the year considered. The amount of monounsaturated fatty acids (MUFA) is several times higher than polyunsaturated ones (PUFA). An increase in PUFA content is present in samples collected in May and July. The oxidation index is near similar for all the samples and this was probably relates with the antioxidant activity of different lipid extracts. The CLA content increases from May to July. Experiments were done also to evaluate eventual differences between morning and afternoon milking. Finally a comparision with fresh ''Pecorino'' and six months aged cheese was determined.The results here reported are of importance since the conjugated linoleic acids (CLA)content in cheese will depend on the CLA content of milk itself and this should be taken into account due to the beneficial effects of CLA isomers in human health. Keywords: sheep milk; fatty acids; CLA; lipid peroxidation; antioxidant activity.