Tuesday, November 2, 2010

Healthy Fruit: Avocado

The avocado (Persea americana) is a tree native to the Caribbean, Mexico, South America and Central America, classified in the flowering plant family Lauraceae along with cinnamon, camphor and bay laurel. Avocado or avocado pear also refers to the fruit (technically a large berry that contains a large seed) of the tree, which may be pear-shaped, egg-shaped or spherical.
Avocados are a commercially valuable fruit and are cultivated in tropical climates throughout the world (and some temperate ones, such as California), producing a green-skinned, pear-shaped fruit that ripens after harvesting. Trees are partially self-pollinating and often are propagated through grafting to maintain a predictable quality and quantity of the fruit. The fruit of horticultural cultivars has a markedly higher fat content than most other fruit, mostly monounsaturated fat, and as such serves as an important staple in the diet of various groups where access to other fatty foods (high-fat meats and fish, dairy, etc.) is limited.
A ripe avocado yields to gentle pressure when held in the palm of the hand and squeezed. The flesh is prone to enzymatic browning and turns brown quickly after exposure to air. To prevent this, lime or lemon juice can be added to avocados after they are peeled. The fruit is not sweet but fatty, distinctly yet subtly flavored, and of smooth, almost creamy texture. It is used in both savoury and sweet dishes, though in many countries not for both. The avocado is very popular in vegetarian cuisine, making a substitute for meats in sandwiches and salads because of its high fat content.
Generally, avocado is served raw, though some cultivars, including the common Hass, can be cooked for a short time without becoming bitter. Caution should be used when cooking with untested cultivars; the flesh of some avocados may be rendered inedible by heat. Prolonged cooking induces this chemical reaction in all cultivars.
It is used as the base for the Mexican dip known as guacamole, as well as a spread on toast, served with spices. Some people enjoy avocado with New Zealand Marmite on toast. In Philippines, Brazil, Indonesia, Vietnam, and south India (especially the coastal Kerala & Karnataka region), avocados are frequently used for milkshakes and occasionally added to ice cream and other desserts. In Brazil, Vietnam, the Philippines, and Indonesia, a dessert drink is made with sugar, milk or water, and pureed avocado. Chocolate syrup is sometimes added.
In Ethiopia avocados are made into juice by mixing them with sugar and milk or water, usually served with Vimto and a slice of lemon. It is also very common to serve layered multi-fruit juice in a glass (locally called 'Spreece') made of avocados, mangoes, bananas, guavas and papayas. Avocados are also used to make salads.
Avocados in savory dishes, often seen as exotic, are a relative novelty in Portuguese-speaking countries such as Brazil, where the traditional preparation is mashed with sugar and lime, and eaten as a dessert or snack. This contrasts with Spanish speaking countries, such as Mexico or Argentina, where the opposite is true and sweet preparations are often unheard of.
In Australia and New Zealand, it is commonly served in sandwiches, on toast, or often with chicken. In Ghana, it's often eaten alone in sliced bread as a sandwich. In Sri Lanka it is a popular dessert once well ripened, flesh is thoroughly mashed with sugar/sugar and milk or treacle (a syrup made from the nectar of a particular palm flower).
In Mexico and Central America avocados are served mixed with white rice, in soups, salads, or on the side of chicken and meat. In Peru avocados are consumed with tequenos as mayonnaise, served as a side dish with parrillas, used in salads and sandwiches, or as a whole dish when filled with tuna, shrimps, or chicken. In Chile it is used as a puree in chicken, hamburgers, and hot dogs; and in slices for celery or lettuce salads. The Chilean version of Caesar salad contains large slices of mature avocado. In Kenya, the avocado is often eaten as a fruit, and is eaten alone, or mixed with other fruits in a fruit salad, or as part of a vegetable salad. In Iran it is used as a rejuvenating facial cream.
Avocado slices are frequently added to hamburgers, tortas, hot dogs, and carne asada.  Avocado can be combined with eggs (in scrambled eggs, tortillas or omelettes).  Avocado is a key ingredient in California rolls and other Makizushi ("Maki", or rolled sushi).  In southern Africa, Avocado Ritz is a common dish.
Nutritional value
Avocados are high in valuable fats and appear to have a beneficial effect on blood serum levels. For a typical avocado:
·    About 75% of an avocado's calories come from fat, most of which is monounsaturated fat.
·    Avocados also have 60% more potassium than bananas. They are rich in B vitamins, as well as vitamin E and vitamin K.
·    Avocados have a high fiber content among fruits - including 75% insoluble and 25% soluble fiber.
·    A fatty triol (fatty alcohol) with one double bond, avocadene (16-heptadecene-1,2,4-triol), is found in avocado.
High avocado intake has been shown to have a beneficial effect on blood serum cholesterol levels. Specifically, after a seven-day diet rich in avocados, hypercholesterolemia patients showed a 17% decrease in total serum cholesterol levels. These subjects also showed a 22% decrease in both LDL (harmful cholesterol) and triglyceride levels and 11% increase in HDL (helpful cholesterol) levels. Additionally a Japanese team synthesised the four chiral components and identified (2R, 4R)-16-heptadecene-1, 2, 4-triol as the natural antibacterial component.

Avocado, raw (edible parts) : Nutritional value per 100 g (3.5 oz)
Energy 670 kJ (160 kcal) | Carbohydrates 8.53 g
Sugars 0.66 g | Dietary fiber 6.7 g | Fat 14.66 g
Saturated 2.13 g | monounsaturated 9.80 g
Polyunsaturated 1.82 g | Protein 2 g
Thiamine (Vit. B1) 0.067 mg (5%)
Riboflavin (Vit. B2) 0.130 mg (9%)
Niacin (Vit. B3) 1.738 mg (12%)
Pantothenic acid (B5) 1.389 mg (28%)
Vitamin B6 0.257 mg (20%)
Folate (Vit. B9) 81 μg (20%) | Vitamin C 10 mg (17%)
Calcium 12 mg (1%) | Iron 0.55 mg (4%)
Magnesium 29 mg (8%) | Phosphorus 52 mg (7%)
Potassium 485 mg (10%) | Zinc 0.64 mg (6%)
Percentages are relative to US recommendations for adults.
Source: USDA Nutrient database

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


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