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Iridaceae comprises 92 genera and 1800 species, included in the monocot, order Asparagales. Plants belonging to Iridaceae are distributed in the tropical and temperate regions of the world, with the greatest diversity in sub-Saharan Africa, followed by South America, Europe and temperate regions of Asia. Iridaceae is considered as one of the most important families in horticulture (Singab et al., 2016).
Plants belonging to Iridaceae have gained interest as ornamentals and in cut-flower industry, especially Iris, Gladiolus, Belamcanda and Freesia. On the other hand, from an economic point of view, Crocus sativus (the source of saffron spice) and Iris (orris root) are considered the most important genera (Singab et al., 2016). Crocus sativus L., commonly known as saffron, is a perennial stemless herb that is widely cultivated in Iran and other countries such as India and Greece.
Commercial saffron comprises the dried red stigma with a small portion of the yellowish style attached. Saffron is used for depression in Persian traditional medicine (Srivastava et al., 2010).
Characteristic components of saffron are crocin (responsible for the color), picrocrocin (responsible for the bitter taste), and safranal (responsible for odor and aroma). Non-volatiles include crocins that are responsible for the red or reddish brown color of stigmas together with carotenes, crocetin, picrocrocin (a glycosidic precursor of safranal), the bitter substance and safranal the major organoleptic principle of stigmas.
However saffron’s golden yellow-orange color is primarily due to α-crocin. This crocin is trans-crocetin di-(β-D-gentiobiosyl) ester.
The crocin underlying saffron’s aroma is a digentiobiose ester of the carotenoid crocetin. Crocins themselves are a series of hydrophilic carotenoids that are either monoglycosyl or di-glycosylpolyene esters of crocetin (Srivastavaet al., 2010