A Spectrophotometric Analysis of Pigments in Apples

Methods of pigment extraction using traditional polar organic solvents (acetone or methanol) were compared to those employing a chloroform–methanol mixture. We found that, for spectrophotometric pigment analysis in the apple peel, the cuticular lipids must be preliminarily extracted from the samples with chloroform and MgO must be added during homogenization to prevent pigment degradation. The traditional extraction did not result in the complete extraction of intact pigments, and such extracts contained a considerable amount of light-absorbing impurities. The application of chloroform–methanol extraction allowed us to markedly reduce the content of such impurities and to increase the accuracy and sensitivity of the measurement of the content of chlorophylls and carotenoids. In addition, this extraction method proved useful for the analysis of phenolic substances (anthocyanins and flavonoids) in the water-methanol fraction of the extracts.