CHARACTERIZATION OF HYDROGENATED FATS FOR MARGARINE MANUFACTURING PURPOSES

Eight samples of hydrogenated vegetable fats were characterized by the ir fatty acid composition, trans isomers content and thermal behaviour , using gas chromatography (GC), infrared spectroscopy (IR), pulsed Nu clear Magnetic Resonance (pNMR) and Differential Scanning Calorimetry (DSC) techniques, respectively. Fatty acid composition showed some var iations in relation to the unsaturated fatty acids. Trans isomer conte nt, values varied from 22.8% to 35.6%. Solid fat content values were m easured using AOCS and IUPAC methods, which differ in the tempering pr ocedures. Values obtained by IUPAC method were higher than the AOCS on es, only at lower temperatures (10 and 21,1 degrees C). Samples were d ivided into three groups according to their solids profile: superior ( C/E/G/H) intermediate (F) and inferior (A/B/D). Melting and crystalliz ation curves were obtained by Differential Scanning Calorimetry. Melti ng enthalpies ranged from 51.3 to 76.5 J.g(-1) and crystallization ent halpies varied from -34.2 to -18.9 J.g(-1) Characteristic temperatures showed little differences between the samples and each of them showed a characteristic DSC curve. All samples showed a great melting range as expected for hydrogenated fats used for margarines manufacture.