Avocado Fruit
The large, lustrous dark green evergreen leaves and
low-branching, open canopy of avocado makes it a wonderful shade tree but it is
most often grown for the abundant production of its well-known, delicious, buttery
fruits. Depending on cultivars and variety, the fruits may vary from
smooth-skinned to rough, and yellow-green to purple and black. Commonly seen at
35 to 40 feet in height but capable of growing much larger, Avocado fits well
into large residential landscapes in frost-protected locations. It can be
pruned to an open spreading form or left to grow tall forming a rather narrow
oval. Older trees become more rounded. The somewhat showy, greenish flowers
appear on terminal panicles in late winter to early spring and are followed by
the large, pendulous, pear-shaped fruits, ripening late summer to early spring,
depending upon variety.
Avocado is a tropical or subtropical fruit native from
South America, which has been referred to as the most nutritious of all fruits.
It is highly valued not only for its unique texture, exquisite taste and aroma,
and nutritional profile, but also for the numerous healthy benefits that it
possesses. For all of this, avocado has gained worldwide recognition and its
consumption has considerably increased in the last years.
Avocados are an ancient fruits and originated from Central
America and Mexico. This bright green fruit with a large pit and dark leathery
skin. They’re also known as alligator pears or butter fruit. These fruits are commonly called as butter fruits
in India. This fruit looks similar to pear fruit. This fruits are good source
of nutrients compared to other fruits.
The avocado is a fast-growing tree that can reach 80ft in
ideal conditions. Trees are usually quite dense in foliage and often have a
spreading growth form. Depending on the climate, avocado's may produce numerous
flushes of new growth each year. The crushed leaves of Mexican varieties have
an anise-like smell. Flowering occurs during winter, prior to vegetative growth
flush. The flowers are formed in large clusters of up to 300 each. From each
cluster only 2-3 fruits or more ( depending on cultivar) will develop. Some
cultivars set fruit every other year, some set fruit yearly. The fruits ripen
6-18 months from flower set, depending on the variety.
These trees can be tall or spreading, and they have
elliptic to egg-shaped leaves that are 10–30 cm in length. The small greenish
flowers are borne in dense inflorescences and lack true petals. The flowers
have nine stamens, arranged in three series, and a one-celled ovary.
Interestingly, there are two types of avocado flowers, A and B, depending on the
cultivar. These flowers are dichogamous (male and female parts mature
separately), and each flower opens only twice. Type A flowers are functionally
female in the morning, close at midday, and then reopen as functionally male in
the afternoon of the following day. Type B flowers are functionally female in
the afternoon, close in the evening, and then reopen the following morning as
functionally male. When the two flower types are grown together, this temporal
overlap of mature male and female parts encourages cross-pollination and, thus,
greater fruit production.
The fruit of this plant, is botanically a large berry
containing a single large seed. Avocados are commercially valuable and are
cultivated in tropical and Mediterranean climates throughout the world. They
have fleshy body that may be pear-shaped, egg-shaped, or spherical.
Commercially, they ripen after harvesting.
Avocado trees are partially self-pollinating, and are often propagated
through grafting to maintain predictable fruit quality and quantity. In 2017,
Mexico produced 34% of the world supply of avocados.
The fruit is exceedingly variable in size, no larger than
a hen’s egg in certain Mexican races and sometimes weighing 1–2 kg (2–4 pounds)
in other races. The form varies from round to pear-shaped with a long, slender
neck, and the colour ranges from green to dark purple. Botanically, the fruit
is a berry and features a single large round seed with two cotyledons. The
fruit’s outer skin is sometimes no thicker than that of an apple and sometimes
is coarse and woody in texture.
The fruit is not sweet, but distinctly and subtly flavoured,
with smooth texture. It is used in both savoury and sweet dishes. The avocado
is common in vegetarian cuisine as 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 variety 'Hass', can be cooked for a short time without
becoming bitter. The flesh of some avocados may be rendered inedible by heat.
Prolonged cooking induces this chemical reaction in all cultivars.
The species is only partially able to self-pollinate
because of dichogamy in its flowering. This limitation, added to the long
juvenile period, makes the species difficult to breed. Most cultivars are
propagated by grafting, having originated from random seedling plants or minor
mutations derived from cultivars. Modern breeding programs tend to use
isolation plots where the chances of cross-pollination are reduced. The avocado is unusual in that the timing of
the male and female flower phases differs among cultivars. The two flowering
types are A and B.
Certain cultivars, such as the 'Hass', have a tendency to
bear well only in alternate years. After a season with a low yield, due to
factors such as cold (which the avocado does not tolerate well) (now some cold
tolerant varieties available), the trees tend to produce abundantly the next
season. In addition, due to environmental circumstances during some years,
seedless avocados may appear on the trees.
The subtropical species needs a climate without frost and
with little wind. High winds reduce the humidity, dehydrate the flowers, and
affect pollination. When even a mild frost occurs, premature fruit drop may
occur, although the 'Hass' cultivar can tolerate temperatures down to -1 °C. Some cold-hardy varieties available, which survive
temperatures as low as -6.5 °C (20 °F) with only minor leaf damage. The trees
also need well-aerated soils, ideally more than 1 m deep.
Indoors, an avocado tree is usually grown from the pit of
an avocado fruit. This is often done by removing the pit from a ripe,
unrefrigerated avocado fruit. The pit is then stabbed with three or four
toothpicks, about one-third of the way up from the flat end. The pit is placed
in a jar or vase containing tepid water. It should split in four to six weeks
and yield roots and a sprout. If there is no change by this time, the avocado
pit is discarded. Once the stem has grown a few inches, it is placed in a pot
with soil. It should be watered every few days. Avocados have been known to
grow large, so owners must be ready to re-pot the plant several times. Propagated by seed, taking roughly four to
six years to bear fruit, although in some cases seedlings can take 10 years to
come into bearing.
Cultivation in Peru, 'Hass' avocado production in Peru
encompasses thousands of hectares in central and western Peru. Peru has now
become the largest supplier of avocados imported to the European Union and the
second largest supplier to Asia and the United States. Peru's location near the
equator and along the Pacific Ocean creates consistently mild temperatures all
year. 'Hass' avocados from Peru are seasonally available to consumers from May
through September and are promoted under the auspices of the Peruvian Avocado
Commission, headquartered in Washington, D.C.
Mexico is by far the world's largest avocado growing
country, producing several times more than the second largest producer. In
2013, the total area dedicated to avocado production was 188,723 hectares
(415,520 acres), and the harvest was 2.03 million tonnes in 2017. The states
that produce the most are México, Morelos, Nayarit, Puebla, and Michoacan,
accounting for 86% of the total. In Michoacán, the cultivation is complicated
by the existence of drug cartels that extort protection fees from cultivators.
They are reported to exact 2000 Mexican pesos per hectare from avocado farmers
and 1 to 3 pesos/kg of harvested fruit.
Cultivation in California, the avocado was introduced
from Mexico to California in the 19th century, and has become a successful cash
crop. About 60,000 acre – some 95% of United States avocado production – is
located in Southern California, with 60% in San Diego County. Fallbrook,
California, claims, without official recognition, the title of "Avocado
Capital of the World" (also claimed by the town of Uruapan in Mexico), and
both Fallbrook and Carpinteria, California, host annual avocado festivals.
Avocado is the official fruit of the state of California.
Commercial orchards produce an average of seven tonnes
per hectare each year, with some orchards achieving 20 tonnes per hectare. Biennial bearing can be a problem, with heavy
crops in one year being followed by poor yields the next.
Like the banana, the avocado is a climacteric fruit,
which matures on the tree, but ripens off the tree. Avocados used in commerce
are picked hard and green and kept in coolers at 3.3 to 5.6 °C (37.9 to 42.1
°F) until they reach their final destination. Avocados must be mature to ripen
properly. Avocados that fall off the tree ripen on the ground. Generally, the
fruit is picked once it reaches maturity; Mexican growers pick 'Hass' avocados
when they have more than 23% dry matter, and other producing countries have
similar standards. Once picked, avocados ripen in one to two weeks (depending
on the cultivar) at room temperature (faster if stored with other fruits such
as apples or bananas, because of the influence of ethylene gas). Some
supermarkets sell ripened avocados which have been treated with synthetic ethylene
to hasten ripening.
Avocados can be propagated by seed, taking roughly four
to six years to bear fruit, although in some cases seedlings can take 10 years
to come into bearing. The offspring is unlikely to be identical to the parent
cultivar in fruit quality. Prime quality varieties are therefore propagated by
grafting to rootstocks that are propagated by seed (seedling rootstocks) or by
layering (clonal rootstocks). After about a year of growing in a greenhouse,
the young rootstocks are ready to be grafted. Terminal and lateral grafting is
normally used. The scion cultivar grows for another 6–12 months before the tree
is ready to be sold. Clonal rootstocks are selected for tolerance of specific
soil and disease conditions, such as poor soil aeration or resistance to the
soil-borne disease (root rot) caused by Phytophthora.
Avocado trees are vulnerable to bacterial, viral, fungal,
and nutritional diseases (excesses and deficiencies of key minerals). Disease
can affect all parts of the plant, causing spotting, rotting, cankers, pitting,
and discoloration. The pyriform scale insect is known from Australia, South
Africa, Israel, Italy, France, Spain, Cuba, Florida, and Peru. It is normally
found on avocado, and in Peru it is said to be the worst insect pest of the
fruit. Certain cultivars of avocado seem more susceptible to attack by the
scale than others.
A typical serving of avocado (100 g) is moderate to rich
in several B vitamins and vitamin K, with good content of vitamin C, vitamin E
and potassium. Avocados also contain phytosterols and carotenoids, such as
lutein and zeaxanthin. Avocados have diverse fats. For a typical avocado, about 75% of an
avocado's energy comes from fat, most of which (67% of total fat) is
monounsaturated fat as oleic acid. Other predominant fats include palmitic acid
and linoleic acid. The saturated fat content amounts to 14% of the total fat.
Although costly to produce, nutrient-rich avocado oil has
diverse uses for salads or cooking and in cosmetics and soap products. Avocados are also a good source of vitamins B,
E, and C, copper and fiber; their potassium content is higher than bananas.
Some Proven Benefits of Avocado
Avocado is incredibly nutritious. They contain more
potassium than bananas. It is loaded
with heart-healthy monounsaturated fatty acids. Avocados are loaded with fiber. Eating avocados can lower cholesterol and
triglyceride levels and help to prevent cancer. Avocado extract may help relieve symptoms of arthritis. The Fat in them can help absorb nutrients
from plant foods. People who eat
avocados tend to be healthier. This fruits
are loaded with powerful antioxidants, that can protect the eyes. Eating
avocado may help lose weight. Avocado is
delicious and easy to incorporate in the diet
Avocado Health Benefits
A healthy lifestyle that includes nutritious food can
help prevent and reverse disease. Avocados are a healthy food you can add. The
vitamins, minerals, and healthy fats you get from avocados help prevent disease
and keep your body in good working order.
Cancer: The folate get from avocados may lower risk of
certain cancers, such as prostate and colon cancer. Nutrients in avocados may
also treat cancer.
Inflammation: Chronic inflammation can kick off many
diseases, including diabetes, alzheimer’s disease, and arthritis. The vitamin E
in avocados lowers inflammation in the body.
Heart: Most of the healthy fat in avocado is oleic acid,
a monounsaturated fatty acid. This heart-healthy fat helps lower cardiovascular
inflammation. Avocados also have a nutrient called beta-sitosterol, the plant
version of cholesterol. Beta-sitosterol helps lower cholesterol levels.
Arthritis and osteoporosis: Studies on oil extracts from
avocados show they can reduce osteoarthritis symptoms. The vitamin K in
avocados boosts bone health by slowing down bone loss and warding off
osteoporosis.
Vision: Lutein and zeaxanthin are two antioxidants in
avocados that are good for eyes. They
help protect the tissues in eyes from UV light damage and help prevent both
cataracts and macular degeneration.
Blood pressure: Avocados are rich in potassium. Potassium
helps level out blood pressure by lowering sodium levels in blood and easing
tension in blood vessel walls.
Depression: Research shows a link between depression and
low levels of folate. Folate helps block the buildup of a substance called
homocysteine in blood. Homocysteine slows down the flow of nutrients to brain
and ramps up depression. The high levels of folate in avocados help to solve this
problem.
Pregnancy: Need at
least 400 micrograms of folate a day during pregnancy to help prevent birth
defects in baby’s brain and spine. One avocado gives around 41% of that.
S
Avocado Allergy
If you have a latex allergy, talk to your doctor before
adding avocado to your diet. People with a serious allergy to latex may also
have symptoms after eating avocado. You may also hear this called latex-food
syndrome or latex-fruit allergy.
Latex products are made from a protein in the sap of the
Brazilian rubber tree (Hevea brasiliensis). Avocados have a very similar
protein, which is what causes the allergic reaction. Your symptoms could be
mild, or they could be serious. They can also get worse each time you have an
avocado.
Medicinal
The avocado has long been used medicinally, with most
parts of the plant being employed. There has been some research into the
medicinal properties of the plant that support traditional uses. Research has shown that there is
anti-cancerous activity in extracts of the leaves and fresh shoots.
Leaf extracts have shown antihypertensive activity. The leaf and seed contain cyanide. The oil from the seeds contains steroids that
are used for pharmaceuticals. The seed extract has an erythroagglutinating
property. The fruit contains reductase
and transferase enzymes.
Other Uses
The
pulp and the seeds contain fatty acids, such as oleic, lanolic, palmitic,
stearic, linoleic, capric and miristic acid which constitutes 80% of the fruits
fatty content. The non-drying oil extracted from the seed is used by the cosmetic
industry in soaps and skin moisturizer products.
The fresh fruit pulp is massaged into the hair and scalp
as a vitamin-rich hair tonic and restorer. A reddish-brown dye obtained from
the seed is used for marking clothes. Watery
extracts of the avocado leaves contain a yellowish-green essential oil. The ground-up seed mixed with cheese is used
as a rat and mouse poison.
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