Processing of Oils and Fats

Abstract

The aim of this article is to provide a review of processing currently in use for refining and modifying oils and fats. The stages in the two principal methods of oil refining are illustrated and a table shows the impurities which are reduced or removed in those stages. It should be borne in mind that oils and fats are natural products and that consequently the impurity levels will vary not only with oil type but also with weather, soil, harvesting, feed, storage and extraction conditions. Therefore, refining plant and procedures should be flexible to allow for these type and quality changes. Commercial pressures also change such that a plant designed for certain oils will be required to deal with very different raw materials. The stages of refining discussed in some detail include - crude oil storage, degumming, neutralization, bleaching, filtration, neutralized and bleached oil storage; deodorization; oil content, physical refining, polishing, and cooling. Modification processes reviewed are hydrogenation (hardening of oils), fractionation, interesterification. Automation of edible oil refineries is also briefly discussed.