Healthy Fruit: Watermelon

Watermelon (Citrullus lanatus, family Cucurbitaceae) can be both the fruit and the plant of a vine-like (scrambler and trailer) plant originally from southern Africa, and is one of the most common types of melon. This flowering plant produces a special type of fruit known by botanists as a pepo, a berry which has a thick rind (exocarp) and fleshy center (mesocarp and endocarp); pepos are derived from an inferior ovary, and are characteristic of the Cucurbitaceae. The watermelon fruit, loosely considered a type of melon (although not in the genus Cucumis), has a smooth exterior rind (green, yellow and sometimes white) and a juicy, sweet interior flesh (usually pink, but sometimes orange, yellow, red and sometimes green if not ripe). It is also commonly used to make a variety of salads, most notably fruit salad.

By the 10th century AD, watermelons were being cultivated in China, which is today the world's single largest watermelon producer. By the 13th century, Moorish invaders had introduced the fruit to Europe; according to John Mariani's The Dictionary of American Food and Drink, "watermelon" made its first appearance in an English dictionary in 1615.

Today, farmers in approximately 44 states in the U.S. grow watermelon commercially, and almost all these varieties have some Charleston Gray in their lineage. Georgia, Florida, Texas, California and Arizona are the USA's largest watermelon producers. This now-common watermelon is often large enough that groceries often sell half or quarter melons. There are also some smaller, spherical varieties of watermelon, both red- and yellow-fleshed, sometimes called "icebox melons".

In Japan, farmers of the Zentsuji region found a way to grow cubic watermelons, by growing the fruits in glass boxes and letting them naturally assume the shape of the receptacle. The square shape is designed to make the melons easier to stack and store, but the square watermelons are often more than double the price of normal ones. Pyramid shaped watermelons have also been developed and any polyhedral shape may potentially also be used.

There are more than 1200 varieties of watermelon ranging in size from less than a pound, to more than two hundred pounds, with flesh that is red, orange, yellow or white. Several notable varieties are included here.

• Carolina Cross: This variety of watermelon produced the current world record watermelon weighing 262 pounds (119 kg). It has green skin, red flesh and commonly produces fruit between 65 and 150 pounds (29 and 68 kg). It takes about 90 days from planting to harvest.
• Yellow Crimson Watermelon: variety of watermelon that has a yellow colored flesh. This particular type of watermelon has been described as "sweeter" and more "honey" flavored than the more popular red flesh watermelon.
• Orangeglo: This variety has a very sweet orange pulp, and is a large oblong fruit weighing 9–14 kg (20–30 pounds). It has a light green rind with jagged dark green stripes. It takes about 90–100 days from planting to harvest.
• The Moon and Stars variety of watermelon has been around since 1926. The rind is purple/black and has many small yellow circles (stars) and one or two large yellow circles (moon). The melon weighs 9–23 kg (20–50 pounds). The flesh is pink or red and has brown seeds. The foliage is also spotted. The time from planting to harvest is about 90 days.
• Cream of Saskatchewan: This variety consists of small round fruits, around 25 cm (10 inches) in diameter. It has a quite thin, light green with dark green striped rind, with sweet white flesh and black seeds. It can grow well in cool climates. It was originally brought to Saskatchewan, Canada by Russian immigrants. These melons take 80–85 days from planting to harvest.
• Melitopolski: This variety has small round fruits roughly 28–30 cm (11–12 inches) in diameter. It is an early ripening variety that originated from the Volga River region of Russia, an area known for cultivation of watermelons. The Melitopolski watermelons are seen piled high by vendors in Moscow in summer. This variety takes around 95 days from planting to harvest.
• Densuke Watermelon: This variety has round fruit up to 25 lb (11 kg). The rind is black with no stripes or spots. It is only grown on the island of Hokkaido, Japan, where up to 10,000 watermelons are produced every year. In June 2008, one of the first harvested watermelons was sold at an auction for 650,000 yen (6,300 USD), making the most expensive watermelon ever sold. The average selling price is generally around 25,000 yen (250 USD).

Nutrition

A watermelon contains about 6% sugar and 92% water by weight. As with many other fruits, it is a source of vitamin C.

Notable is the inner rind of the watermelon, which is usually a light green or white color. This area is edible and contains many hidden nutrients that most people avoid eating due to its unappealing flavor.

The amino acid citrulline was first extracted from watermelon and analysed. Watermelons contain a significant amount of citrulline and after consumption of several kg, an elevated concentration is measured in the blood plasma; this could be mistaken for citrullinaemia or other urea cycle disorders.

Watermelon rinds are also edible, and sometimes used as a vegetable. In China, they are stir-fried, stewed or more often pickled. When stir-fried, the de-skinned and de-fruited rind is cooked with olive oil, garlic, chili peppers, scallions, sugar and rum. Pickled watermelon rind is also commonly consumed in the Southern US. Watermelon juice can also be made into wine.

Watermelon is also mildly diuretic.

Watermelons contain large amounts of beta carotene.

Watermelon with red flesh is a significant source of lycopene.

Watermelon, raw (edible parts)

Nutritional value per 100 g (3.5 oz)

Energy 127 kJ (30 kcal) | Carbohydrates 7.55 g

Sugars 6.2 g | Dietary fiber 0.4 g

Fat 0.15 g | Protein 0.61 g | Water 91.45 g

Vitamin A equiv. 28 μg (3%) | Vitamin C 8.1 mg (14%)

Thiamine (Vit. B₁) 0.033 mg (3%)

Riboflavin (Vit. B₂) 0.021 mg (1%)

Niacin (Vit. B₃) 0.178 mg (1%)

Pantothenic acid (B₅) 0.221 mg (4%)

Vitamin B₆ 0.045 mg (3%) | Folate (Vit. B₉) 3 μg (1%)

Calcium 7 mg (1%) | Iron 0.24 mg (2%)

Magnesium 10 mg (3%) | Phosphorus 11 mg (2%)

Potassium 112 mg (2%) | Zinc 0.10 mg (1%)

Percentages are relative to US recommendations for adults.

Source: USDA Nutrient database

Source, Images: http://en.wikipedia.org/wiki/Watermelon