Application of UV-visible spectrophotometry to study of the thermal stability of edible vegetable oils

Abstract

The thermal s tabi l i ty of three ol ive oils of different characteristics, under atmosphere of air, nitrogen and oxygen has been studied, by means of simultaneous thermal analysis (TG-TGD)UV-visible spectrophotometry. The specific extinction coefficient values of the oils at 232 and 270 nm were calculated at different temperatures from room temperature to those corresponding to the 10% of the thermogravimetric curve. The results show the negative influence of the temperature and the oxidant atmosphere on the thermal stability of the oils; this is verified by the increase of the coefficients K232 and K270 and by the decreasing of the degradation beginning temperature under such atmospheres, compared with the results obtained under inert atmosphere. On the other hand, in this work is made evident a high correlation between the obtained data from thermal analysis and those obtained from UV-visible spectrophotometry.

Keywords

• olive oil
• thermal analysis
• thermal stability
• uv-visible spectrophotometry