Broccoli become popular as quick-frozen vegetables, particularly.

Broccoli have been classified in convar. botrytis (L.) Alef., as var. botrytis L. and var. italica Plenck, respectively. In broccoli the single headed ‘calabrese’ type with a compact dome-shaped head with small beads (flower buds) is grown worldwide, under conditions comparable to the summer types of temperate cauliflower. The buds are preferably dark green.


Broccoli probably evolved in Roman times from wild or primitive cultivated forms of Brassica oleracea from the eastern Mediterranean region. A remarkable diversity of broccoli-like vegetables developed in Italy. During the last 400 years, white-headed cauliflower spread from Italy to central and northern Europe, which became secondary centres of diversity for annual and biennial types.Broccoli with one main green ‘head’ (calabrese) was introduced into the United States by Italian immigrants during the early 20th century. From the United States it has spread throughout the world in the last 50 years.


Broccoli are grown for their large, edible, very young inflorescence. Cauliflower heads (curds) and in broccoli the heads and the fleshy upper portion of the stem are mostly consumed as a cooked vegetable; sometimes they are cut into small pieces (florets) and used raw in mixed salads or in pickles. Broccoli, and to a lesser extent cauliflower, have become popular as quick-frozen vegetables, particularly in the United States and Europe.
Broccoli seed (6% moisture content) will remain viable for at least 4–6 years when stored dry at temperatures below 18°C. Seeds germinate within 3–6 days and seedlings have 7–9 true leaves within 30–40 days at > 20°C average daily temperatures.


Total world production of broccoli in 2017 is 26.0 million tonnes, with China and India together accounting for 73% of the world total. Secondary producers, each having about one million tonnes or less annually, were the United States, Spain, Mexico and Italy.Important broccoli producing areas are: North America 56,000 ha, Europe 45,000 ha, Latin America 8000 ha and Asia 17,000 ha.


Broccoli contain various bioactive compounds such as flavonoids and hydroxycinnamoyl derivatives. They also contain glucosinolates, which are responsible for the characteristic flavour and taste, and some of them have strong anticarcinogenic properties. In cauliflower the main glucosinolate is sinigrin, in broccoli glucoraphanin. Sulforaphane, a breakdown product of glucoraphanin, has shown anticancer activity in rats and humans against several forms of cancer. It is a potent inducer of enzymes that protect cells against electrophile toxins including carcinogens; it also upregulates the synthesis of hepatic detoxification enzymes. The glucosinolate content is influenced by ecological factors (e.g. soil S content) and cultivar.


Author：P. Tjeertes, Netherlands

References

Holland, B., Unwin, I.D. & Buss, D.H., 1991. Vegetables, herbs and spices. The fifth supplement to McCance & Widdowson’s The Composition of Foods.
Shinohara, S. (Editor), 1984. Vegetable seed production technology of Japan.
Whitwell, J.D., Jones, G.L. & Williams, J.B., 1982. Cauliflowers.