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A . P f a l z g r a f , M . F r i g g , H . S t e i n h a r t , M . K i r c h g e f l n e r a48 pigs (gilts and barrows) were divided into four groups and fed for three months on diets containing either 3 % soya oil or 3 % beef tallow, together with a-dl-tocopheryl acetate at either a basal (20 mg/ kg feed) or a supplemented (200 mg/kg feed) level. The fatty acid compositions of the longissirnus dorsi muscle (m.1.d.) and adipose (backfat) tissue were found to vary with dietary fats and sex. Gilts showed higher contents of polyene fatty acids (PFA) than barrows. The PFAs C20:4w6, C22:4w6, C22:503 and C22:6w3 were not affected by the diet. Levels of a-tocopherol in muscle and adipose tissue were 2.5 to 4.0 times higher in pigs on the supplemented diet compared to pigs on the basal diet. After storage at -18°C for nine months the muscle tissues were subjected to iron-induced lipid peroxidation. Supplementation of the feed with a-tocopheryl acetate improved the oxidative stability of the muscle. The influences of dietary fat and sex on lipid peroxidation were reduced by supplemental a-tocopheryl acetate. Muscle tissue from the basal-diet/soya-oil group was more susceptible to lipid oxidation than muscle tissue from the basal-diet/beef-tallow group. I n t r o d u c t i o nDuring the storage and preparation of meat, many primary and secondary oxidation products such as aldehydes, dialdehydes, ketones, esters, furans, alcohols, hydrocarbons and lactones are formed'. These volatile compounds, together with break-down products of the amino acids, affect flavour and aroma2. T h e occurrence of warmed-over flavour in cooked meat products, caused by the oxidation of phospholipids3, is a well-documented example of the importance of controlling lipid oxidation in meat. Feeding pigs with vitamin E at high levels increases the a-tocopherol content of the membranes4. The formation of thiobarbituric-acid-reactive substances (TBARS) during storage' and the induced oxidation of fresh neat^.^ is delayed by feeding vitamin E a t higher levels.Stability against oxidation is influenced not only by the levels of antioxidants but also by the fatty acid composition of the meat'. This is also a determining factor for the flavour of pork'. A s early as 1926, Ellis and Isbell'o*'' demonstrated that the fatty acid composition of pork fat was dependent o n the types of fat consumed with the feed. There was a particularly good correlation in the case of linoleic acid. * Dedicated to Prof. Dr. A. Monfag on the occasion of his 65'h birthday. 48 Schweine wurden in vier Gruppen iiber einen Zeitraum von drei Monaten vor der Schlachtung mit Futter unterschiedlicher Fettsiurezusammensetzung und Vitamin E-Erganzung gemastet. Als Fettkomponente enthielten die Rationen j e 3 % Sojaal oder Rindertalg mit Vitamin E-Zusatze? (a-dl-Tocopherylacetat) von 20 bzw. 200 mglkg Futter. Die Fettsaurezusammensetzung im Musculus longissimus dorsi (m.1.d.) und im Auflagenfett wurde durch das Nahrungsfett und das Geschlecht beeinflunt. Weibliche Tiere wiesen hohere Gehal...

The fatty acid composition of the fat in 197 food samples has been analyzed by gas liquid chromatography. The use of a 30 m capillary column coated with CPSil88 permitted the separation of the cis and trans isomers. The trans fatty acid content of milk and milk products ranged from 1.9 to 7.9%. Meat samples from ruminants contained 2.0-10.6% trans fatty acids. In pork fat the amounts were less than 0.5%. Sausages and other meat products contained high levels of pork fat. Therefore these samples contained less than 1% trans fatty acids, with the exception of some pure beef products. The amounts of trans fatty acids in foods which may contain hydrogenated oils ranged from 0 to 34.9%. In food samples with high levels of trans fatty acids lower contents of saturated fatty acids were analyzed.

A fast, sensitive and reproducible method for the analysis of alpha-tocopherol in pork tissues is presented. It combines saponification of the tissue and alpha-tocopherol extraction in a single vessel, followed by HPLC separation and fluorescence detection. Added alpha-tocopherol was recovered quantitatively. The reduction of lipid peroxides with potassium iodide before the saponification step did not alter the amounts of alpha-tocopherol detected. Membrane-bound alpha-tocopherol was not oxidized by lipid peroxides during the procedure. The coefficient of variation of alpha-tocopherol analysed using this method was +/- 4.2% for muscle and +/- 2.5% for adipose tissues.

Butter is rich in lauric, myristic, and palmitic acids which are assumed to be hypercholesterolemic. The replacement of usual dietary fat by rapeseed oil induces a serum cholesterol decrease. The objective of the study consisted in measuring the influence of feeding different amounts of full-fat rapeseed or oil-rich rapeseed cake to dairy cows to improve the fatty acid composition of milk fat. The results demonstrate a significant increase of iodine number and spreadability of butter. The percentage of lauric+myristic+palmitic acid (LMP) decreased by about 18% of whole fatty acids. Stearic and oleic acid increased significantly but the percentage of trans octadecenoic acid increased too. It can be concluded that the special butter has a nutritionally improved fat characterized by an increase of cholesterol-lowering fatty acids (C18 and C18:1) and a decline of cholesterol-elevating fatty acids (LMP).