Discussion 78 Determination of oil in feeding stuffs by extraction with petroleum spirit

The official EC method may be downloaded from:

http://europa.eu.int/eur-lex/en/lif/dat/1998/en_398L0064.html This is document 398L0064 (which is presented in the Official Journal No. L257, 19.09.98, pp.14-28), and is the Commission Directive 98/64/EC of 3 September 1998. The determination of crude oils and fats appears as Part B of the Annex. Two procedures are described: Procedure A is the directly extractable crude oils and fats applicable to feed materials of plant origin and is a simple extraction with petroleum spirit (light petroleum, boiling range 40-60°C); Procedure B is total crude oils and fats, and applies to feed materials of animal origin and to all compound feeds. It consists of a preliminary heating with 3 M HCl followed by filtration, washing, drying and then Procedure A is carried out. If oil is seen at the filtration stage, then the EC method recommends that Procedure A is carried out first, and then Procedure B. This double extraction procedure, based on SI 1985 No. 1119, is described in MAFF (1993a). Padmore (1990, p. 79) describes the AOAC method for crude fat (or ether extract) in plants or animal feed, which omits the HCl digestion step. We will first describe a basic extraction procedure, then a method suitable for rapeseed. See the discussion in Chapter 4 'Oils, fats and waxes'.

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