Chlorophylls and their derivatives during drying of sultana grapes

Abstract

AbstractUntreated berries of Vitis vinifera and berries treated with commercial dipping solution were dried in the dark, full shade or in the sun. Dipping treatment increased the drying rate.The major pigments, namely, chlorophyll a, chlorophyll b, pheophytin a, pheophorbide a and the carotenoids, decreased in all treatments where berries received light. Only the chlorophylls and carotenoids decreased in berries dried in the dark, but not to the same extent as in berries exposed to light during drying. Pigment loss was not directly related to berry moisture content.Berries dried in the dark remained green while berries dried in the light changed to brown if untreated or pale golden‐brown if treated with commercial dipping solution. In situ removal of the magnesium from the magnesium porphyrin compounds demonstrated that the green coloration was due to the chlorophylls and chlorophyllides.