Onion is an annual herbaceous plant. It is an important type of vegetable cultivated all over the world. It contains varieties with different shell colours and can be harvested in spring and autumn. Especially winter varieties harvested in autumn are richer in content. It is consumed fresh in the form of green and dried onion.
It is an important source of vitamin A, C and B vitamins. Onions contains a large amount of chemical compounds such as allicin, quercetin, fisetin and other sulphurous compounds. It also contains dialyl disulphide and dialyl trisulphide. It is also rich in iodine, calcium, iron, folate, magnesium, phosphorus, potassium and antioxidants.
Other compounds: Protocatechuic, vanillic acids, ferulic acid, p-coumaric, cyaniding, Peonidin, pelargonidin, Isoeugenol, Hydroxytyrosol, Sylvopinol, p-Octopamine, 4-Methylcatechol