Relationships between nitrate, chlorophyll and chromaticity values in rocket salad and parsley

Abstract

The relationships between nitrate concentration, total chlorophyll, chlorophyll a and b concentrations, chromaticity values L*, a*, b*, hue and chroma in parsley (Petroselinum crispum Mill.) and rocket salad (Eruca sativa Mill.) were investigated. Every month, during 2004 and 2005, three samples for each leafy vegetable were obtained from the market, and after the measurement of colour with a tristimulus colorimeter as Commission Internationale De L'eclairage L*a*b*, nitrate, total chlorophyll, chlorophyll a and b concentrations were determined analytically. Correlation analysis showed that in both vegetables, there were highly significant correlations (P<0.001) between nitrate, total chlorophyll, chlorophyll a, L* and a* values, and it was possible to estimate total chlorophyll and nitrate concentrations by L* or a* values.

Key words: Eruca sativa Mill., Petroselinum crispum Mill., nitrate concentration, leaf colour.