Fourier Transform Infrared Spectroscopic Analysis of Butter Made from Vegetable Oil and Pure Cow Milk Subjected to Thermo-oxidation Processes

Fatty acids, mainly unsaturated ones during a thermo-oxidative treatment can produce isomers and oxidation products, which consumed in high concentrations have a negative effect on health. Therefore, the objective of this work was to identify fatty acids in butter and margarine subjected to a thermo-oxidative treatment in order to determine their quality. Commercial brand butter and margarine were purchased. The thermo-oxidative treatment was carried out at 200°C during 30 min. To identify the fatty acids, Fourier transform infrared spectroscopy (FTIR) was used in the middle region (400-4000 cm-1). It was identified that saturated and unsaturated fatty acids did not show chemical changes and oxidative degradation products. A minimum strength in the absorbance corresponding to the double bonds with trans configuration was determined, due to the origin of the raw material. Therefore, the conditions of the thermo-oxidative treatment do not generate changes in the chemical structure of the fatty acids.