GREEN COLOR DEVELOPMENT IN POTATO COOKING WATER

The aim of this study was to determine the cause of green colour devel opment in water used for cooking new potatoes. Evidence, from studies on rates of pigment formation, on spectral changes and on gel filtrati on chromatography, strongly favours chlorogenic acid and amino acids b eing involved. In particular, the reaction between chlorogenic acid an d glutamine that occurs under mildly alkaline conditions, like those o f the potato cooking water, led to a mixture of blue-green and brown p igments with properties similar to the green water colouring matter. C hlorogenic acid and asparagine gave a pigment mixture spectrally simil ar to the glutamine-derived pigment and may also contribute to the gre en cooking water colour.