Vegetables World : Spinach

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The origin of spinach (Spinacia oleracea L.) has been placed near Iran where it has been cultivated for at least 2000 years. Its cultivation in North Africa and Europe began about 1000 A.D. Related wild types are S. tetranda, a possible ancestor, and S. turkestanica. Spinach is an annual plant grown in temperate regions exclusively for its leaves. The spinach root system consists ofmany shallow fibrous laterals developing from a slightly thickened taproot, with few large laterals. Soon after the seedling stage, plants assume a rosette growth habit with many fleshy leaves attached to a short stem. Spacing and environmental conditions influence leaf number and size. Leaf blades range from ovate or nearly triangular to long and narrow arrowhead shapes, the latter is a characteristic of primitive types. Leaf margins are smooth or wavy and surfaces are smooth, semi savoy to heavily savoyed. (Rubatzky and Yamaguchi, 1997).

Spinach is an extremely nutritious vegetable, rich both in core nutrients and phytochemicals. The major micronutrients in spinach are vitamins A (from β-carotene), C, K and folate, and the minerals, calcium, iron and potassium. Spinach also provides fibre and is low in calories. The phytochemicals of most importance are the carotenoids, β-carotene, lutein and zeaxanthin and phenolic compounds. A number of studies have shown spinach to have strong antioxidant activity and high levels of antioxidant compounds such as phenolics and carotenoids. Antioxidant activity is important as many chronic diseases and health issues associated with ageing are believed to result from excessive oxidative stress. One of the major health benefits attributed to two major compounds in spinach, lutein and zeaxanthin, is that of protecting against eye diseases such as macular degeneration (gradual loss of central vision, associated with old age). Epidemiological and laboratory studies have also shown that spinach, spinach extracts, and spinach compounds may delay or retard agerelated loss of brain function, reduce the extent of post-ischaemic stroke damage to the brain, and protect against cancer through various different mechanisms (Hedges and Lester, 2007).

Vegetables World : Carrot

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Carrot (Daucus carota L., var. sativus Hoffm.) is the major vegetable umbellifer cultivated worldwide. It has a crisp texture when fresh. The most commonly eaten part of a carrot is a taproot, although the greens are sometimes eaten as well. It is a domesticated form of the wild carrot Daucus carota, native to Europe and southwestern Asia. The domestic carrot has been selectively bred for its greatly enlarged and more palatable, less woody-textured edible taproot. Cultivated carrots can be separated into two types: eastern/Asiatic and western. Eastern/Asiatic carrots have reddish purple (anthocyanin-containing) or yellow roots, pubescent leaves which give a grey-green appearance, and a tendency for early flowering. Western carrots have orange, yellow, red or white roots, less pubescent green leaves, and less tendency to bolt without extended exposure to low temperatures. (Rubatzky and Quiros, 1999)

The chemical composition of carrot roots for most cultivars is about 88% water, 7% sugar, 1% fibre, 1% protein, 1% ash and 0.2% fat. Thiamine, riboflavin, niacin, folic acid and vitamin C are also present in appreciable amounts Crude fibre in carrot roots consists of cellulose, hemicellulose and lignin, with cellulose being the most abundant. Although reference is sometimes made to starch in carrots (Holland et al., 1992) the starch content of roots is generally close to nil. The anthocyanin content in carrot roots can vary from trace amounts in orange roots to more than 1700 mg kg^–1 in purple or black carrots (Mazza and Miniati, 1993).

Vegetables World : Lettuce

Green leafy vegetables are a good source of fiber, folate, and carotenoids. These vegetables also contain vitamins C and K and the minerals iron and calcium. Green vegetables also act as antioxidant. The substance in green vegetables removes free radical from our body. Lettuce is one of green vegetables that you should consider as your daily diet. Lettuce is low in calories and sodium. Lettuce free of fat and cholesterol. The best part Lettuce is inexpensive and available year-round. Eating ½ cup shredded or raw Romaine Lettuce your body will get a lot of nutrition. ½ cup lettuce contains 38 mcg Folic acid, 7 mg Vitamin C, 73 RE Vitamin A and 0 cholesterol.  Hohl et al. (2001) reported that head lettuce contains glycosides which are largely concentrated on the outer leaves and have antioxidative activity. The high magnesium content in the lettuce is good for the brain, nerves and muscular tissue. Lettuce has an impact on conditions such as insomnia, constipation, pregnancy and lactation, and menstrual disorders.

Most lettuces are eaten uncooked and are popular salad vegetables because of their color, texture, and flavor contribution to meals. Often the major component of vegetable salads, lettuce has a high water and low carbohydrate and protein content. Nevertheless, because of the volume annually consumed (about 12 kg per capita in the United States) lettuce is recognized for its nutritional contribution of minerals, provitamin A, vitamin C, fiber, and bulk. Cos- and leaf-type lettuces provide more pro vitamin A because of a greater proportion of green leaves compared to crisphead types. (Rubatzky and Yamaguchi 1997)