AbstractThe supply and demand of edible oils and fats is briefly reviewed, and certain trends, relevant for the application of fat modification techniques, are noted. The effect of hydrogenation conditions on a number of selectivity aspects in hydrogenation with nickel catalysts is explained in terms of mass transport effects for hydrogen and triglycerides. The effect of selectivity on stability and melting behavior is also discussed. The limitations of the existing hydrogenation process with nickel are pointed out, and possible extensions by use of other catalysts, such as sulphur poisoned nickel, copper, and chromium complexes, are mentioned. Some technological aspects of the process are briefly reviewed.