Claeys Erik, Vossen Els, De Smet Stefaan
Laboratory for Animal Nutrition and Animal Product Quality, Department of Animal Production, Ghent University, 9090, Melle, Belgium.
J Sci Food Agric. 2016 Jan 30;96(2):522-9. doi: 10.1002/jsfa.7119. Epub 2015 Feb 27.
The analysis of α-tocopherol in feed and animal-derived foods usually involves a saponification step. However, since saponification often leads to losses of α-tocopherol, a method for the determination of α-tocopherol in feed and in animal-derived foods was developed without a saponification step.
In this method, α-tocopherol is extracted with hot ethanol and the co-extracted fat is removed by centrifugation. Removal of the fat fraction is made possible by the addition of water, to achieve an ethanol:water ratio of 40:7, followed by cooling on ice before centrifugation. This procedure allows removal of the fat fraction, while α-tocopherol is retained. Matrices differing in gross composition and α-tocopherol content were analyzed: fresh pork, cooked ham, subcutaneous fat, liver, egg yolk, milk and a compound pig feed. Higher α-tocopherol concentrations were found for this novel method compared to a conventional method with saponification, particularly for subcutaneous fat (P < 0.05). Recoveries were higher (P < 0.05) for the novel method (82-103%), compared to the saponification method (66-90%; for subcutaneous fat < 25%).
Determining α-tocopherol in feed and animal-derived foods using pure ethanol without saponification results in higher extraction yields and recoveries compared to the saponification method.
饲料和动物源性食品中α-生育酚的分析通常涉及皂化步骤。然而，由于皂化常常导致α-生育酚损失，因此开发了一种无需皂化步骤的饲料和动物源性食品中α-生育酚的测定方法。
在该方法中，用热乙醇提取α-生育酚，并通过离心去除共提取的脂肪。通过加水使乙醇与水的比例达到40:7，然后在离心前在冰上冷却，从而实现脂肪部分的去除。该程序能够去除脂肪部分，同时保留α-生育酚。分析了总成分和α-生育酚含量不同的基质：新鲜猪肉、熟火腿、皮下脂肪、肝脏、蛋黄、牛奶和复合猪饲料。与传统皂化方法相比，该新方法检测到的α-生育酚浓度更高，尤其是皮下脂肪（P < 0.05）。新方法的回收率（82-103%）高于皂化方法（66-90%；皮下脂肪低于25%）（P < 0.05）。
与皂化方法相比，使用纯乙醇且不进行皂化来测定饲料和动物源性食品中的α-生育酚，提取率和回收率更高。
