GB582557A - Improvements in the fractionation of glyceride oils - Google Patents

Abstract

Oils of the drying and semi-drying type are fractionated into a fraction more saturated and another fraction more unsaturated than the original oil by mixing the oil with an organic solvent, rapidly chilling the mixture so as to precipitate the more saturated fraction in a flowable form and separating the precipitate in a continuous centrifuge. The precipitate is preferably in an amorphous or very fine crystalline form capable of flowing through the centrifuge for continuous separation as opposed to the ordinary crystalline form separable by filtration which packs or interlocks in the ordinary batch centrifuge. Non-polar solvents are preferred such as petroleum ether, hexane, trichlorethylene and any other hydrocarbons or chlorinated hydrocarbons; polar solvents such as acetone or furfural are less preferred in view of their tendency to produce ordinary crystals but they may be used if the conditions are controlled particularly as to the rate of chilling and the proper degree of agitation so as to minimise crystal formation. In general, 1 part of oil to 1-20 parts of solvent is used. The oil solvent mixture is agitated during the chilling operation, the oil being chilled to a temperature of -20 DEG F. to -60 DEG F. The solvents may be recovered from each of the fractions obtained. The process is particularly adapted for soya bean oil, linseed oil, fish oils, and less usefully for cottonseed oil, the so-called reversion factor of these oils associated with certain odour and taste characteristics being retained in the more unsaturated fraction where it is not objectionable in paints &c. The more saturated fraction is adaptable for edible purposes &c. Specifications 402,651 and 439,128 are referred to.