(57) A method for treating an edible oil rich in linoleic acids so as to increase its solid fat content comprises the directed interesterification under isothermal conditions of an oil containing at least 60% pufa and 12.5 to 16% safa, with preferably at least a part of the safa being hydrogenated, having been cooled to its interesterification temperature at a cooling rate of between 5°C/min and 5°C/s. The method is simple to perform and produces an oil which can be employed directly in margarine manufacture. The oil can be a mixture of an oil high in pufa such as natural sunflower and safflower seed oil and an oil high in safa such as fully or partially hardened sunflower or safflower seed oil. The initial rapid cooling rate can increase the rate of development of solid fat phase during the interesterification step.