CRUCIFERAE (BRASSICACEAE) (Mustard family)
This family includes some 350 genera and well over a thousand species, of which a number are utilized as vegetables. Cruciferous vegetables are rich in essential nutrients. They are known to reduce the risk of cancer,81,82 and should therefore fill a prominent position in the diet. Because vegetables in general, and cruciferous vegetables in particular, contain substantial quantities of sulphur, the vitamin C-concentration does not decline as readily as it does in the case of fruits
or vegetables with a lower sulphur content,91 and this means that more of this vitamin is retained after storage and cooking.
Some of the common vegetables in this family are those which belong to genus Brassica, which includes broccoli, brussels sprouts, cabbage, Chinese cabbage, cauliflower, kale, kohlrabi, rutabaga and turnips. Some other important foods from this family include cress, watercress, and radish, which are eaten in salads, and Japanese horseradish and mustard which are used as condiments. The chemical components of the mustard family, to which its anti-cancer properties are attributed, are listed in table 7.18. One of these substances is mustard oil which also is responsible for the characteristic taste of the cabbage group, and the compounds attributed with anti-cancer activity are isothiocyanytes, thiocyanates and dithiolthiones.
Broccoli (Brassica oleracea)
Broccoli was developed in Italy and is well established as one of the major anti-cancer foods. It also stimulates the production of enzymes which rid the body of potentially harmful metabolites.81 Broccoli contains some 3% of protein and is one of the richest vegetable sources of calcium, iron and magnesium. Moreover, broccoli is very rich in vitamins A and C, exceeding even oranges in the concentration of the latter. Broccoli can be eaten raw in salads or with dips, or it can be steamed and eaten as is, or served with a light nut, or similar sauce.
Brussels sprouts (Brassica oleracea)
Brussels sprouts was first developed in Belgium from where it also gets its name. Brussels sprouts is quite popular in Europe and its nutrient composition is similar to that of broccoli, except that the concentrations of vitamins and minerals tend to be lower. Use brussels sprouts as an alternative to provide variety, but try to use fresh or frozen sprouts as they lose their flavour and texture when canned.
Cabbage (Brassica oleracea)
Cabbage is yet another variety of the species Brassica oleracea which is rich in cleansing minerals such as sulphur. It is native to the Mediterranean region, England and France, but the cultivated form was introduced to Britain by the Romans. Cabbage can be eaten raw, pickled or cooked and is used in a great variety of ways. There are many varieties of cabbages but the Savoy cabbage is considered to be the best in terms of its nutrient content. Savoy cabbage contains some 157mg of vitamin C per 100g and is rich in sulphur, a cleansing mineral, which helps to retain this vitamin.
Cabbage can be fermented to produce Sauerkraut, a process whereby the bacterium Lactobacillus converts the sugars into lactic acid, which accounts for the sour taste of Sauerkraut. Lactic acid is a weak acid, and in spite of its presence, Sauerkraut still remains an extremely alkaline-forming food which supplies an abundance of vitamins and minerals. The body copes well with lactic acid, and Sauerkraut can be eaten without fear of acid build up. Red cabbage is another variety of cabbage which can also be eaten raw in salads, or it can be cooked with a little lemon juice, rather than vinegar, to give it a sour flavour. Another popular cabbage variety, that can be used to provide variety, is the Chinese cabbage which is good for making salads or cooked as a green vegetable.
Cauliflower (Brassica oleracea)
Cauliflower is probably native to Asia Minor but was known in Europe by the sixteenth century. Its nutrient composition does not compare with that of broccoli, but it is an excellent source of biotin, and other vitamins and minerals are in good supply. Cauliflower provides that necessary variety on the table and it can be eaten raw, cooked and served with a sauce or as a soup, and it lends itself to being crumbed.
Kale and collard (Brassica oleracea)
Kale is similar to cabbage, but the leaves, which are green, silver-green or purple, do not form a head. The varieties that are used for human consumption are usually those with the curled leaves, and in the USA there is a variety that also forms a rosette of leaves similar to cabbage, but not compact. This variety is known as collard. Kale is the oldest variety of Brassica and it is very rich in nutrients. Kale is rich in calcium, magnesium, vitamin B6, and it contains over 7 400 IU of vitamin A per 100g.
Kohl-rabi (Brassica oleracea)
The name Kohl-rabi is a German name which means ‘cabbage turnip,’ and it is the swollen turnip-like stem which is used as a vegetable. The leaves are not usually eaten, but they are edible and do have considerable nutritive value. Kohl-rabi is normally cooked and can be served with a white nut, or similar sauce, and it is excellent in soups.
Turnip (Brassica rapa)
The turnip has been used for thousands of years, and is native to temperate parts of Europe and Asia. The swollen base can be cooked and eaten sliced and the leaves can be used like spinach. Turnips are not used extensively except in poorer areas, and they do not excel in any particular nutritional component, although they do contain reasonable amounts of calcium and vitamin C.
Radish (Raphanus sativus)
Radishes were used by the ancient Egyptians and they are probably native to Asia. Their pungent taste is due to the mustard oil. Radishes are eaten raw, and when they are peeled, most of the enzyme responsible for the production of mustard oil is removed, and they have a milder taste. The leaves of the radish should not be thrown away, as they can be used in salads, but as they are slightly prickly, they are best used in soups to create a pleasant, spicy taste. Radish-leaf soup is pleasant as a starter to meals, and is prepared by cooking the leaves and creaming them in a blender. Radishes contain fair amounts of vitamin C, and the mineral silicon is also in good supply.
Cress (Lepidium sativum)
Both garden cress and watercress (Nasturtium officinale) are members of the cruciferous family and their taste is due to mustard oil. They are used raw in salads or in soups and stews, and have a fresh spicy taste. Watercress was originally used as a medicine, and in view of its superb composition, it should become a part of every household’s menu. Watercress is an excellent source of calcium (120mg per 100g), magnesium and phosphorous, and it contains 4 700 IU of vitamin A per 100g. The B-group vitamins are well supplied and the concentrations of vitamins C and E are also above average.