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Avocado

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In terms of biological classification avocado is a fruit but since it is predominantly used in savoury dishes it is referred to as a vegetable. An avocado is closer to a berry in botanical terms. In some respects it is a tropical fruit akin to a banana, but its oily content and nutty flavor reminds one of an olive. It should be quite soft before opening and eating. It is a fruit with a leathery skin and soft, buttery flesh; it yields to light pressure when ripe. Avocado is also known as the “alligator pear” because of the rough skin that some varieties have. Sliced Avocado


Contents

[edit] Common Name

Avocado, Alligator Pear (English); Aguacate, Palta (Spanish)

[edit] Species

Persea species, Lauraceae

Guatemalan (Persea nubigena var. guatamalensis L. Wms.), Mexican (P. americana var. drymifolia Blake), West Indian (P. americana Mill. var. americana). Hybrid forms exist between all three types.

  • Related species: Coyo (Persea schiedeana Nees), Anay (Beilschmiedia anay Kosterm)

[edit] Description

  • Growth Habit
    • The avocado is a dense, evergreen tree, shedding many leaves in early spring.
    • It is fast growing and can with age reach 80 feet, although usually less, and generally branches to form a broad tree. Some cultivars are columnar, others selected for nearly prostrate form. One cultivar makes a good espalier.
    • Growth is in frequent flushes during warm weather in southern regions with only one long flush per year in cooler areas.
    • Injury to branches causes a secretion of dulcitol, a white, powdery sugar (dulcitol can, after recrystallization be used, as a sugar-free sweetener), at scars.
    • Grafted plants normally produce fruit within one to two years compared to 8 - 20 years for seedlings.
  • Foliage
    • Avocado leaves are alternate, glossy, elliptic and dark green with paler veins. They normally remain on the tree for 2 to 3 years.
    • The leaves of West Indian varieties are scentless, while Guatemalan types are rarely anise-scented and have medicinal use.
    • The leaves of Mexican types have a pronounced anise scent when crushed. The leaves are high in oils and slow to compost and may collect in mounds beneath trees.
  • Flowers

Avocado flowers appear in terminal panicles of 200 - 300 small yellow-green blooms. Each panicle will produce only one to three fruits.

  • Fruits
    • West Indian type avocados produce enormous, smooth round, glossy green fruits that are low in oil and weigh up to 2 pounds.
    • Guatemalan types produce medium ovoid or pear-shaped, pebbled green fruits that turn blackish-green when ripe.
    • The fruit of Mexican varieties are small (6 - 10 ounces) with paper-thin skins that turn glossy green or black when ripe. The flesh of avocados is deep green near the skin, becoming yellowish nearer the single large, inedible ovoid seed. The flesh is hard when harvested but softens to a buttery texture. Wind-caused abrasion can scar the skin, forming cracks which extend into the flesh.
    • Off-season fruit should not be harvested with the main crop, but left on the tree to mature. Seeds may sprout within an avocado when it is over-mature, causing internal molds and breakdown.

[edit] Adaptation

Avocados do well in the mild-winter areas of California, Florida and Hawaii. Some hardier varieties can be grown in the cooler parts of northern and inland California and along the Gulf Coast. The northern limits in California is approximately Cape Mendocino and Red Bluff.

  • Avocados do best some distance from ocean influence but are not adapted to the desert interior.
  • West Indian varieties thrive in humid, tropical climates and freeze at or near 32° F.
  • Guatemalan types are native to cool, high-altitude tropics and are hardy 30 - 26° F.
  • Mexican types are native to dry subtropical plateaus and thrive in a Mediterranean climate. They are hardy 24 - 19° F. Avocados need some protection from high winds which may break the branches.
  • There are dwarf forms of avocados suitable for growing in containers.
  • In India, avocados grow in South India especially areas around Saligao, Bangalore etc

[edit] History

Historically it can be traced back to about 7000 BC where it was said to be enjoyed by the Aztec and Inca people. There are also records of its cultivation from 6000 B.C. in Oaxaca, and of its continuous use at all levels in all of the famous archaeological sites in Mexico, including Tehuacán in Puebla, where the earliest maize fossils appeared.

In these old habitations, the evidence is a seed. The seeds were small for thousands of years before there was selection for the large fruits that we find today in the stores and market places.

There is also strong evidence that avocado trees flourished 50 million years ago in California and might have provided food for dinosaurs. The name comes from the Nahuatl word ahuacacuahtl which means testicle. Some say this is because the avocado has aphrodisiac properties, though the Aztecs were probably noting the shape and the fact that they grow in twos.

[edit] Nutrients

The avocado is almost perfect in terms of the nutrients it contains and can be called an almost perfect food. Avocados are full of nutrints such as vitamins, A, B-complex, C, E, H, K, and folic acid, plus magnesium, copper, iron, calcium, potassium and many other trace elements. Avocados provide all of the essential amino acids, with 18 amino acids in all, plus 7 fatty acids, including Omega 3 and 6. In fact, avocados contain more protein than cow’s milk while a small avocado will provide more protein than a huge steak. This is because cooked protein in meat gets deranged and mostly unavailable to our liver, the organ which makes all of our body’s protein. On the other hand, ripe, organically grown avocados are naturally pure and contain all of the elements needed to build the highest quality protein in our bodies. The fats it contains are of the mono-unsaturated kind, which does not lead to an increase in blood cholesterol levels. Avocados are also extremely rich in potassium with every 100 grams containing 450mg of the nutrient. Another metal which avocado is rich in is copper with every 100 grams containing about 0.2 grams of the nutrient.

[edit] Traditional Uses

  • Ancient Chinese medicine used avocados to help harmonize the liver while lubricating the lungs and intestines. These benefits can be claimed of avocados due to their cooling nature.
  • Avocados are extremely rich in copper and therefore help in the formation of red blood cells.
  • As avocados are very easily digested by the human digestive system they are an ideal remedy for ulcers.
  • Avocados have a high vitamin E content and therefore said to be very helpful in curing dermatological ailments as well as burns.

[edit] Health Benefits

  • Heart Diseases

The high vitamin E content in avocados is associated with a reduced risk of cardiovascular disease. This is likely due to the fact that low density lipoprotein (LDL) cholesterol is protected by vitamin E from damage by free radicals in the blood. If the LDL cholesterol is damaged it is to lead to likely blockage in the blood vessel walls. Stopping LDL damage thus helps decrease cardiovascular problems. In most food forms the vitamin E content is destroyed as the body processes the foods. While consuming avocados one has the advantage that no processing is required.

  • Infertility in Men

Vitamin E also plays a very important role in improving sperm count and mobility. Along with vitamin C it seems to play a role in stopping the sperm from grouping together and thus providing greater mobility in the journey to the egg.

  • Parkinson’s Disease

Recent scientific research has shown people with a certain form of Parkinson’s are offered some protection from the disease if they consume a diet that is rich in vitamin E, thus making avocado an ideal food choice.

Avocado vs. Meat

  • Avocado is fiber-rich and does not cause constipation. Meat has low water and no and is constipating
  • Avocado has all the essential amino acids while the amino acids present in get denatured when the meat is cooked.
  • Avocado has zero cholesterol while meat is extremely high in cholesterol
  • Avocado takes only 2 to 4 hours to digest while meat takes 12 to 24 hours.
  • Avocado has no parasites, pathogens or tumors, meat has incidences of several varieties of parasites and pathogens.
  • Organically grown avocados are not inoculated with any chemicals while meat is inoculated with antibiotics, medicines and hormones
  • Avocado does not need cooking. Eating meat raw increases the parasite-pathogen risk. When meat is cooked the fats become carcinogenic, the proteins coagulate, and the minerals become embedded as arterial and bowel plaque leading to atherosclerosis, heart disease, Alzheimer’s, etc.
  • Avocado is healthy to eat while meat is linked to major health hazards such as cancer, colitis, diabetes, obesity and many other diseases.
  • Avocado is alkalinizing, meat acidifying

[edit] Uses of the Avocado Oil

Avocado oil is not derived from the seed but is pressed from the fleshy pulp surrounding the avocado pit. The oil has a unique, nutty flavour and some say it has the aroma of globe artichokes and celery, with the rich, lingering flavour of avocado. It is usually produced from avocados that are damaged or not aesthetically pleasing.

  • Uses in Cooking

It can be used in whipped potatoes, drizzled over steamed vegetables, in vinaigrette dressings, for sautéing, soups ands stews. Avocado oil has a high smoke point (255 C) and can be infused with lemon, rosemary, basil or chili.

  • Benefits of avocado oil to the skin
    • In a study done at the Department of Food Engineering and Biotechnology, Technion-Israel Institute of Technology in 1991, it was found that avocado oil significantly increases the amount of collagen in the skin - which normally is under attack as we grow older. This oil has a high level of sterolins(also called plant steroids), which are reputed to reduce age spots, help heal sun damage and scars.
    • It is also used for people with dry or mature skins, or people suffering from eczema or psoriasis.

[edit] Consumption and Storage

  • How to buy
    • While buying avocados ensure that you buy ones that are well shaped without any bruises or blemishes.
    • For immediate use buy those avocados that yield when pressed around the neck. Ripe, ready-to-eat fruit will be firm yet will yield to gentle pressure.
    • Colour alone may not tell the whole story. The Hass avocado will turn dark green or black as it ripens, but other varieties retain their light-green skin even when ripe.
  • How to ripen an avocado
    • If you plan to serve the fruit in a few days, stock up on hard, unripened fruit and then store them with a banana in side a paper bag for a few days for ripening at room temperature until ready to eat (usually two to five days). Including a banana in the bag accelerates the process because these fruits give off ethylene gas, a ripening reagent.
    • Soft ripe fruit can be refrigerated until it is eaten, but not for more than two or three days.
  • How to eat avocado

While preparing the avocado cut in halves along the length of the avocado then twist to separate the halves and remove the stone. Then it can either be served in the skin or scoop out to be added to soups, dips or cubed and added to salads.

  • Storing or Freezing Avocados
    • Ripe fruit can be stored in the refrigerator uncut for two to three days.
    • To store cut fruit, sprinkle it with lemon or lime juice or white vinegar and place in an air-tight container in your refrigerator. If refrigerated guacamole turns brown during storage, discard the top layer.
    • If you have a large quantity of fresh avocados, it's a good idea to freeze them. Pureed avocados freeze very well and can be used in salads, sandwiches and dips.
    • Wash, seed and peel the fruit as described above.

Puree the flesh, adding one tablespoon of lemon juice for each two pureed avocados. Pack the puree into an air-tight container, leaving 1 inch of headspace. Freeze and use within four to five months.

[edit] Culinary Uses

  • Avocado Fruit
    • Halve and pit avocado then scoop carrot atcks into it and eat as a snack.
    • Add to salads.
    • Mix avocados with chopped bell pepper, onions, tomato, celery,or fresh coriander, lime juice etc. to make a guacamole or salsa.
    • Add avocado to your favourite creamy tofu dressigrecipe to give it an extra richness and beautiful green colour.
    • Serve as hors d’oeuvres by slicing chunks and inserting toothpicks.
    • Add to processed vegetable slaw, vegetable loafs and vegetable cakes.
    • Mix into vegetable soups-- either blend in to make a creamy texture or serve in little chunks. It tastes great in a black bean soup.
    • Spread ripe avocados on bread as a healthy replacement for mayonnaise when making a sandwich.

Note: For optimum digestion, eat avocado alone or with any non-sweet-non-starchy fruit or any non-starchy vegetable food. Eating avocado with leafy greens, celery and/or cucumber will enhance the digestive process as additional digestive.

  • Avocado leaves

Both fresh and dried are used in the cuisine's of the South Central part of Mexico.
Fresh Leaves
Fresh leaves are used in Oaxaca as a bed for barbecuing meats as well as a flavoring for tamales.
Dried Leaves
Dried avocado leaves are most frequently available in the U.S. and can be used in soups and stews as well as bean recipes. Diana Kennedy suggests using the leaves as a substitute for hoja santa.

[edit] Cautions

  • Avoid avocados when on a weightloss diet

The vegetable is extremely rich in calories as well as fats, thus should be eaten sparingly by those who are dieting.

  • Avocados cause allergic reactions in people with sensitivity to latex

Avocados contain enzymes called chitinases that can cause allergic reactions in people with sensitivity to latex. Therefore, individuals with latex sensitivity should avoid eating or touching avocados.

  • Avoid ethylene gas treated Avocados- buy organic

The treatment of avocados with ethylene gas to induce ripening can increase the presense of these allergenic enzymes; therefore it is best to buy organic avocados not treated with ethylene gas.

  • Toxicity to animals

There is documented evidence that animals such as cats, dogs, cattle, goats, rabbits, birds, fish and particularly, horses can be severely harmed or even killed when they consume the avocado leaves, bark, skin, or pit. The avocado fruit is poisonous to birds in some cases, so on a practical level feeding the fruit to birds should be avoided.

This is a traditional view held by bird owners, yet other owners have fed avocados to their birds with no abnormal incidences at all.

Avocado leaves contain a toxic fatty acid derivative known as persin, which in sufficient quantity can cause equine colic and, with lack of veterinary treatment, death. The symptoms include gastrointestinal irritation, vomiting, diarrhea, respiratory distress, congestion, fluid accumulation around the tissues of the heart and even death. Birds also seem to be particularly sensitive to this toxic compound. Negative effects in humans seem to be primarily in allergic individuals [1].

[edit] Some avocado myths & facts

  1. It’s a vegetable. Fact: It’s actually an oily berry--a fruit.
  2. It’s high in cholesterol. Fact: It has no cholesterol. Only animal foods have cholesterol.
  3. It’s high in fat. Fact: By weight, avocados average 30% easily digestible oily fatty acids and approximately 70% water.
  4. Its saturated fat content is dangerous. Fact: Only about 2.5% of the edible portion of avocado is saturated fat, and unheated saturated fat from live plant foods is non-toxic.
  5. It’s fattening. Fact: It is the cooked starches, meat, dairy and processed sugar in people’s diets that feed their fat cells. Most active people who consume avocados as part high raw food vegan diet have no problem losing excess fat and staying lean.
  6. It is a tree ripened fruit. Fact: The avocado doesn't soften on the tree. After dropping or picking it must be allowed to soften for 4 to 17 days depending on the variety and ambient temperature and humidity.

[edit] Growing Avocados

There are three races of Avocado in cultivation, Mexican, Guatemalan, and West Indian with multiple hybrids. The Mexican varieties are the hardiest and bear fruit with smoother, thinner shiny green skin. Guatemalan avocados need frost free climates and can be identified by their blackish, green, thick, bumpy rinds. West Indian fruit are the most frost sensitive and are identified by thin, smooth, greenish-yellow skin.

These are sub-tropical fruits, so if you grow them in non native locations, there are going to be quite a few challenges.

  • How to grow an avocado from seed
    • Plant the seed immediately after eating the avocado.
    • Poke three toothpicks into the side of the seed so that it can perch, halfway immersed in water, on the rim of a drinking glass. The seed could also be planted in potting soil, but this misses some of the fun of watching the roots and the shoots grow.
    • Avocado roots, like those of most other plants, need oxygen, so the seedlings would actually grow better in soil than in water. When growing a seedling in water, the water should be changed at least every couple of weeks, before it gets dirty and depleted of oxygen. One way to speed germination in soil is to remove the parchment like seed coat and slice a thin layer from both the top and the bottom of the seed before planting. In water or in soil, set the seed with its base (the wider portion) down.
  • Location is one of the most important considerations in successfully growing an avocado tree. Avocado trees do not have bark to protect themselves from the intense sun and must be planted undershade. Natively the tree would grow under the shade of the parent plant and as it matures it would eventually break through the upper canopy.
  • Soil and Watering
    • Avocados need a well drained soil, as the plant will not tolerate wet soggy soil, this is also important in the winter time when the ground is cold as well. This does not mean that the tree is drought tolerant. It cannot take the desert heat and arid conditions. It needs regular deep watering especially as temperatures reach well above 100f degrees in the summer.
    • Avocados are very sensitive to salt burn, and therefore a high concentration of salt in the water is likely to bump off your tree. So if your soil has a high salt content, drip irrigation is the best bet or the hose on to just a trickle.
  • Fertilizing, frost protection and general care
    • Avocados do not neet pruning except where you need to control spread or height. Pruning should be done before flower set and flush of new growth. Depending on how old your avocado tree is and what variety, you may need to provide frost protection.
    • Fertilizing is usually not recommended for young and newly planted trees for at least the first year. Once the tree is established you can use any balanced feed of compost, coffee grounds, fish emulsion, etc.
  • Getting rid of pests, fungus and root rot

Neem and Neem Oil based non toxic broad spectrum pesticides should be used.

[edit] References

[edit] To Buy Avocado Oil

[edit] Recipes with Avocados, Avocado Leaves and Avocado Oil

[edit] See Also

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