The chemical elements that give the saffron its specific organoleptic qualities are: crocetin, crocin, picrocrocin and safranal. These four molecules all derive from a single precursor, the zeaxanthin carotenoid, from which they derive by enzymatic degradation, by a specific dioxygenase. Crocetin is a fairly unusual carotenoid, characterized by a chain of 20 carbon atoms and the presence of two carboxyl groups, positioned one at each end of the chain. These groups can undergo esterification reactions which in saffron preferentially involve a particular sugary structure, the diglucoside p-D-genziobiosio; the reaction gives rise to crocin, a water-soluble glycosylated form of crocetin which determines the intense color typical of saffron. Other carotenoids present in flower stigmas such as 3-crocetin (monometilcrocetin) also determine the spice color. dimethylcrocetin), a-carotene, 3-carote¬ne, lycopene and the same crocetin and zeaxanthin. The safranal, the main component of the essential oil, is responsible for the characteristic smell of saffron, while the bitter taste is due to the presence of picrocrocin, a glyconic form of the safranal. However, other chemical elements are also present in the spice including alkaloids, saponins and phytosterols. There are also sugars, minerals, B vitamins, in particular vitamin B and B2, as well as volatile compounds such as a and 13-pinene and eucalyptol. A good quality saffron should contain about 30% of crocin, between 5 and 15% of picrocrocin and 2.5% of volatile compounds including the safranal.