上海地区部分市售食品中反式脂肪酸含量与组成分析

目的了解上海地区部分市售食品中的反式脂肪酸(trans-fatty acids,TFAs)含量以及异构体组成,为开展TFAs的风险评估和食品选择提供参考。方法于2011年1～6月在上海市超市、面包店或快餐店中抽取具有代表性的9大类共106种市售食品,包括植物油、乳及乳制品、休闲食品、方便食品、快餐食品、饮料、小吃甜饼、调味品和畜禽肉及制品,采用银离子固相萃取(Ag+-SPE)结合气相色谱方法检测TFAs含量。结果抽检样品中的TFAs以反式油酸(t C18∶1)为主,反式多不饱和脂肪酸含量较少。除黑咖啡外,其余105种食品均检测到TFAs,其中,巧克力派的TFAs含量最高(1 711.58 mg/100 g)。反刍动物食品和含乳及乳制品的食品中11t C18∶1异构体含量较高(占总TFAs的53.9%～100.0%)。富含氢化油的休闲食品中9t C18∶1异构体含量较高(占总TFAs的14.3%～87.7%)。猪肉和牛肉经加工后TFAs含量有不同程度降低。结论市售食品中普遍检测到TFAs,食物成分和加工过程不同总TFAs含量及异构体组成存在较大差异,预包装休闲食品和西式甜饼店食品含有较多的TFAs。

Analysis of trans-fatty acids contents and composition in some commercially available foods in Shanghai

Objective To investigate trans-fatty acids(TFAs) contents and composition in some commercially available foods of Shanghai,and provide reference for risk assessment and food selection.Methods During January~June 2011,9 categories and totally 106 kinds of representative sold foods from Shanghai supermarket,bakery and fast food restaurant were assayed by silver ions solid phase extraction-Gas chromatography(Ag+-SPE/GC),including vegetable oil,milk and milk products,snacks,convenience foods,handy foods,beverages,ethnic foods and cakes,condiments and poultry meat and products.Results Trans-oleic acids(t C18∶1) were main kinds of TFAs isomer in samples selected,and trans-polyunsaturated fatty acids only accounts for a small part.TFAs were found in 105 kinds of all the 106 products with black coffee an exception,in which chocolate pie was the highest content of TFAs(1 711.58 mg/100 g).11t C18∶1 isomer was relative high within ruminant animal foods and foods containing milk and milk products(accounting for 53.9%-100.0% of total TFAs).9t C18∶1 isomer was relative high in snacks containing hydrogenated oil(accounting for 14.3%-87.7%).TFAs contents of pork and beef processed were reduced to different extents.Conclusion According to the test,most commercially available foods in markets contain the TFAs,among whose ingredients and processing procedures diversify the total TFAs contents and the composition of isomers greatly.Some kinds of prepackaged snacks and foods from western cake stores contain more TFAs.