How harvest, cleaning and conservation good practices affect the quality of saffron: results of a research conducted in Italy

Saffron (Crocus sativus L.) spice making requires time-spending manual operations: stigmas are separated from the flower picked in bud early in the morning, and once dried they are preserved protected from light. This study verified how the correct pursuing of these good practices affects saffron quality. Few hours of exposure of the flower to the sun determined a significant decrease in the colouring strength (239.66 ± 10.33 versus 255.35 ± 11.87). The correct cleaning of stigmas determined a very significant increase of colouring strength (247.12 ± 13.32 instead of 224.35 ± 14.88) and a significant increase of flavour strength (99.72 ±7.48 against 90.31 ± 6.32, p <0.05). In 24 months, all the samples kept in the dark were still of first category of quality while the ones kept in the light dropped in second category. For all samples there was an increase of aroma strength and a decrease of the flavour and colouring strength, but only the colouring strength loss followed a significantly more sloping trendline. A detectable difference in the content of trans-crocin 4 correlated to the ageing or the way of conservation was not found, nevertheless, it was confirmed that the isomers tend towards a photostationary state where the trans isomer is more present.