Effect of the Temperature and Oxidation Time on Some Physicochemical Characteristics of the Rice Bran Oil

Abstract

Due to their excellent characteristics, vegetable oils are successfully used in various formulations of organic lubricants. In this context, the advanced biodegradability and excellent lubricity performance of rice oil leads to its being considered as a real potential for the lubricants industry. However, as with other vegetable oils, the stability of rice bran oil is strongly influenced by the oxidation process. Therefore, the aim of this work was the oxidation stability monitorization of rice bran oil by spectrophotometric techniques. For this purpose, oxidation tests of rice bran oil at elevated temperatures were performed.In this paper, transmittance spectra were determined, and the trichromatic components and coordinates were calculated, as well as the colour differences for rice oils subjected to a forced oxidation treatment at temperatures of 100 °C and 120 °C for 4, 8 and 10 hours. The results obtained show that, although after the first 4 hours of forced oxidation significant changes appear on the physicochemical properties of rice bran oil, an increase in the test time from 8 to 10 hours does not lead to significant changes in the analysed parameters, the conclusion being valid for both test temperatures.