抄録
The developments of a red colour in frying oils during high temperature are practically important having close relations with the foarming tendencies. In this report, soybean oils were used as the representative of frying oils, and their chromaticy changes when heated were measured by the three methods; Lovibond method, RGB chromaticy method and XYZ chromaticy method. Among them, XYZ chromaticy method was the best to analyse the chromaticy changes indicating the highest sensibility. Then the highly coloured soybean oils were reduced with sodium borohydride, lithium alminium hydride and hydrazine hydrate, and by determining the characteristics and infrared spectra, carbonyl groups and epoxy groups were found to partake the developments of a red colour.Then the reduced material by the use of sodium borohydride was treated with marcuric acetate for addition and the infrared spectroscopic analysis of this material showed that the carbonyl groups having close relations with the red colour development seemed to be α, β- and α, α'-unsaturated carbonyls.
