Determination of the Amount of trans‐Octadecenoate and trans‐9,trans‐12‐Octadecadienoate in Fresh Lean and Fatty Tissues of Pork and Beef

Longissimus muscle and subcutaneous fat from 17 pork and 6 beef carcasses were analyzed for trans-octadecenoates and trans-9,trans-12-octadecadienoate (linolelaidate) content by argentation thin layer chromatography and/or glass capillary gas liquid chromatography. No detectable amount of trans-9,trans-12-octadecadienoate was found in pork or beef. In pork the amount of trans-octadecenoates ranged from 0.0074 – 0.0077 g/100g of fresh Longissimus muscle and 0.1453 – 0.1549 of fresh subcutaneous fat. The content of trans-octadecenoates in beef ranged from 0.0782 – 0.0839 g/100g of fresh Longissimus muscle and 2.4280 – 2.7368 g/100g of fresh subcutaneous fat. The content of trans fatty acids contributed by pork and beef to the human diet is negligible relative to that derived from other dietary sources.