Model fat blends with different structured fats concentration were prepared and their physical and chemical properties were studied. Structured fats were made by interesterification of fully hydrogenated oils: zero-erucic rapeseed oil or palmstearin with coconut oil. Fat blends were studied with respect to crystallization and rheological properties. Rheological parameters such as yield stress and yield stress by Haighton are proportionally dependent on the concentration of structured fats in the fat blends and inversely proportional on the concentration of the coconut oil in structured fats. Two types of crystals were found in the fat blends: beta', mixture of beta' and beta, but pure beta crystals were not detected. The tendency to form crystals with modification beta', which is required in margarine production, is influenced by increasing of the coconut oil concentration and independent on the palmitic/stearic acid ratio in the structured fat. Rate of the cooling had strong influence on the yield stress value. (c) 2005 Elsevier Ltd. All rights reserved.