Palm oil fractionation

Abstract

Modification techniques like fractionation, interesterification (chemical or enzymatic) and hydrogenation allow proposing a large range of new fatty products. At a time when "trans" fatty acids are questioned, fractionation of fats and oils catches more and more interest; in this context, dry fractionation is by far the simplest and cheapest fractional crystallization technique (no chemicals, no effluent and no losses). The oil processing industry uses dry fractionation to extend the application of a whole variety of fatty matters as well as to replace, fully or partially, the chemical modifications. Due to the continuous developments of the dry fractionation process, a whole variety of products normally produced by solvent fractionation can now be obtained with a high degree of selectivity with dry fractionation. As the crystallization operates in the bulk, viscosity problems limit the degree of crystallization in one single step, and multi-step operations are currently used, giving rise to a wide range of fractions suitable for different applications. The secret is to combine proper crystal development with highly efficient separation by using membrane press filters allowing squeezing out the stearin cake for as much liquid occlusion (olein) as possible. The original booming of the dry fractionation process has helped mostly palm oil to conquer a strong position on the commodity market in one single stage; today, palm oil is without doubt the most widely fractionated oil. New demands for special cuts drifted the industry towards a more sophisticated approach: high-iodine value super and top oleins, palm red fractions (high carotene and tocopherol/ tocotrienol contents) or solvent-free cocoa butter equivalents (palm mid fractions) are certainly what the future has in store. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.