Development of an image algorithm to assess changes in leaf pigments content of fresh-cut spinach and lettuce leaves.

The aim of this work was to develop an image algorithm to detect changes in colour related with changes in leaf pigments content in leafy spinach during storage. The experiment was carried out on packed ready-to-use spinach stored at 4.5 °C. Seventy-five leaves of spinach were analyzed at zero time and after storage for 7, 14 and 21 days. Multispectral images were acquired in the red (R), infrared (IR) and blue (B) regions. Virtual images were calculated on the basis of spectral indexes usually employed for estimation of leaf pigment content. By considering the sensitive bands to chlorophyll and carotenoids, new virtual images were proposed. A no supervised classification was applied to the obtained virtual images and the results were evaluated according to colorimetric measurements (CIE L*a*b* coordinates). The new proposed indexes were able to correctly classify a high percentage of the samples according to the colour evolution