Content of chlorophylls and carotenes in rapeseed oil

Abstract

AbstractThe content of the green components in crude rapeseed oil, namely chlorophylls A and B, as well as the products of their decomposition pheophytins A and B, were determined by means of the spectrophotometric method of analysis.No chlorophyll A was found in any of the analyzed samples but the content of pheophytin A was quite high and amounted to from 17.99 to 25.65 ppm. Because of the fact that the oils were investigated 5 to 6 months after their extraction, the results obtained are not unexpected, bearing in mind that chlorophyll contained in oil easily changes into pheophytin.No chlorophyll B was found in some of the samples, investigated and in the remaining samples from 0.14 to 1.79 ppm was found. This can be explained by the hypothesis of slower change of chlorophyll B into pheophytin B.The content of pheophytin B in the investigated samples was between 0.52 and 6.15 ppm. This confirms the results obtained by Mingot (3). With old oils, the results of determining such components, whose content approaches nil in the sample, are less precise because of the influence of the oil which was used as a blank.The content of carotenes in crude rapeseed oils was also determined by the spectrophotometric method after isolating them by means of the column chromatography on Al2O3.In spite of the small amount of carotenes determined in rapeseed oils, a correlation can be observed between the quantity of chlorophylls and carotenes. It has been found that the higher the chlorophyll content, the higher also the carotene content, even if very slight in some cases, in all the investigated oils either extracted or pressed.