title: Determination of α-tocopherol by reversed-phase HPLC in feed and animal-derived foods without saponification.
abstract: BACKGROUND
  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.
  
  
  RESULTS
  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%).
  
  
  CONCLUSIONS
  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.
authors: Laboratory for Animal Nutrition and Animal Product Quality, Department of Animal Production, Ghent University, 9090, Melle, Belgium.
authors: Erik
authors: E
authors: Claeys
authors: Laboratory for Animal Nutrition and Animal Product Quality, Department of Animal Production, Ghent University, 9090, Melle, Belgium.
authors: Els
authors: E
authors: Vossen
authors: Laboratory for Animal Nutrition and Animal Product Quality, Department of Animal Production, Ghent University, 9090, Melle, Belgium.
authors: Stefaan
authors: S
authors: De Smet
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004530:Egg Yolk / Q000737:chemistry*; D005504:Food Analysis / Q000379:methods; D008099:Liver / Q000737:chemistry; D008460:Meat / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D050151:Subcutaneous Fat / Q000737:chemistry; D013552:Swine; D024502:alpha-Tocopherol / Q000737:chemistry*
chemical_list: D024502:alpha-Tocopherol
keywords: egg; fat; feed; meat; milk; vitamin E