Food in Focus - Avocados
Description Colloquially known as the 'alligator pear', avocados are the fruit of the Persea americana, a tall evergreen tree which flourishes in tropical and subtropical climates.
Whilst dozens of varieties of avocados have been identified, they predominantly fall into three categories - Guatemalan, Mexican and West Indian.
The most popular types of avocado in the United Kingdom are the Guatemalan Hass which has pebbled, purple-black skin; and the Mexican Fuerte which is larger in size with smooth, dark green skin and a more defined pear shape.
In addition to their appearances, these varieties differ in taste in that the Hass has a higher oil content than the Fuerte, affording a more buttery texture.
Nutritional Profile The avocado is considered a 'complete' food whereby it provides in excess of 25 essential nutrients, including: vitamins A, B, C, E and K, iron, copper, phosphorus, magnesium, and potassium.
Indeed, you would need to eat two or three bananas to obtain the potassium content of one avocado.
Avocados also provide protein, fibre and beneficial phytochemicals such as beta-sitosterol, glutathione and lutein.
Moreover, the avocado has a fat content approximately 20 times the average of other fruits.
It should be noted, however, that the avocado's high-fat content consists largely of the healthy monounsaturates, namely oleic acid and linoleic acid.
Therapeutic Benefits The avocado's nutritional profile boasts an array of health-promoting properties - antioxidant activity, heart, eye, kidney and prostate health, to name but a few.
The avocado's therapeutic benefits, however, are largely due to its high content of monounsaturated fats.
These are known to improve skin texture, boost energy production, lubricate and reduce inflammation in joints, support the immune system, increase metabolism, and they can actually help you burn excess adipose fat.
Another advantage of monounsaturated fat is its ability to lower artery-clogging LDL cholesterol and raise heart-healthy HDL cholesterol.
The avocado's ability to lower cholesterol is further attributed to its beta-sitosterol content.
This beneficial plant-based fat appears to block absorption of the 'bad' LDL cholesterol from the intestine, resulting in lower blood cholesterol levels.
Indeed, research indicates that merely eating half an avocado daily can reduce levels of blood cholesterol by two points in four months.
Finally, avocados act as a nutrient 'booster' when combined with specific foods.
The absorption of fat-soluble nutrients - alpha- and beta-carotene, for example, is enhanced when eaten in combination with the fruit.
Enjoying a few slices of avocado in a mixed salad or salsa, therefore, not only enhances texture and flavour, but will greatly increase your body's ability to absorb the health-promoting carotenoids offered by vegetables.
Safety Avocados contain enzymes called chitinases that can cause allergic reactions in people with sensitivity to latex.
The treatment of avocados with ethylene gas to encourage ripening can increase the presence of these allergenic enzymes.
To reduce your exposure to these compounds, I would recommend that you opt for organic avocados that have not been treated with ethylene gas.
Selection & Storage A ripe, ready-to-eat avocado is slightly soft, but should have no dark sunken spots or cracks.
Avoid Fuertes with skin that is too light and bright.
If the avocado has a slight neck, rather than being rounded on top, it is likely to have been tree-ripened and will be more flavoursome.
A firmer, less mature fruit can be ripened at home in a paper bag or in a fruit bowl at room temperature.
As the fruit ripens, the skin will turn darker.
Avocados should not be refrigerated until they are fully ripe.
At this stage, they can be stored in the fridge for up to a week - provided they have not been sliced.
The natural darkening of the avocado flesh that occurs with exposure to air can be prevented by a little sprinkling of lemon juice or vinegar.
Serving Suggestions Spread mashed avocados on bread or toast as a healthy alternative to butter or mayonnaise in sandwiches.
Fill a wholemeal tuna pitta pocket with sliced avocado, tinned tuna, red onion and a drizzle of olive oil and lime juice.
Guacamole:Avocado, onion, garlic, tomato and lime juice whizzed in a blender.
Serve with strips of wholemeal pitta bread and raw carrot sticks.
Poached salmon served with new potatoes and avocado salsa (diced red onion, tomato, mango, avocado, fresh coriander and lemon juice)
Whilst dozens of varieties of avocados have been identified, they predominantly fall into three categories - Guatemalan, Mexican and West Indian.
The most popular types of avocado in the United Kingdom are the Guatemalan Hass which has pebbled, purple-black skin; and the Mexican Fuerte which is larger in size with smooth, dark green skin and a more defined pear shape.
In addition to their appearances, these varieties differ in taste in that the Hass has a higher oil content than the Fuerte, affording a more buttery texture.
Nutritional Profile The avocado is considered a 'complete' food whereby it provides in excess of 25 essential nutrients, including: vitamins A, B, C, E and K, iron, copper, phosphorus, magnesium, and potassium.
Indeed, you would need to eat two or three bananas to obtain the potassium content of one avocado.
Avocados also provide protein, fibre and beneficial phytochemicals such as beta-sitosterol, glutathione and lutein.
Moreover, the avocado has a fat content approximately 20 times the average of other fruits.
It should be noted, however, that the avocado's high-fat content consists largely of the healthy monounsaturates, namely oleic acid and linoleic acid.
Therapeutic Benefits The avocado's nutritional profile boasts an array of health-promoting properties - antioxidant activity, heart, eye, kidney and prostate health, to name but a few.
The avocado's therapeutic benefits, however, are largely due to its high content of monounsaturated fats.
These are known to improve skin texture, boost energy production, lubricate and reduce inflammation in joints, support the immune system, increase metabolism, and they can actually help you burn excess adipose fat.
Another advantage of monounsaturated fat is its ability to lower artery-clogging LDL cholesterol and raise heart-healthy HDL cholesterol.
The avocado's ability to lower cholesterol is further attributed to its beta-sitosterol content.
This beneficial plant-based fat appears to block absorption of the 'bad' LDL cholesterol from the intestine, resulting in lower blood cholesterol levels.
Indeed, research indicates that merely eating half an avocado daily can reduce levels of blood cholesterol by two points in four months.
Finally, avocados act as a nutrient 'booster' when combined with specific foods.
The absorption of fat-soluble nutrients - alpha- and beta-carotene, for example, is enhanced when eaten in combination with the fruit.
Enjoying a few slices of avocado in a mixed salad or salsa, therefore, not only enhances texture and flavour, but will greatly increase your body's ability to absorb the health-promoting carotenoids offered by vegetables.
Safety Avocados contain enzymes called chitinases that can cause allergic reactions in people with sensitivity to latex.
The treatment of avocados with ethylene gas to encourage ripening can increase the presence of these allergenic enzymes.
To reduce your exposure to these compounds, I would recommend that you opt for organic avocados that have not been treated with ethylene gas.
Selection & Storage A ripe, ready-to-eat avocado is slightly soft, but should have no dark sunken spots or cracks.
Avoid Fuertes with skin that is too light and bright.
If the avocado has a slight neck, rather than being rounded on top, it is likely to have been tree-ripened and will be more flavoursome.
A firmer, less mature fruit can be ripened at home in a paper bag or in a fruit bowl at room temperature.
As the fruit ripens, the skin will turn darker.
Avocados should not be refrigerated until they are fully ripe.
At this stage, they can be stored in the fridge for up to a week - provided they have not been sliced.
The natural darkening of the avocado flesh that occurs with exposure to air can be prevented by a little sprinkling of lemon juice or vinegar.
Serving Suggestions Spread mashed avocados on bread or toast as a healthy alternative to butter or mayonnaise in sandwiches.
Fill a wholemeal tuna pitta pocket with sliced avocado, tinned tuna, red onion and a drizzle of olive oil and lime juice.
Guacamole:Avocado, onion, garlic, tomato and lime juice whizzed in a blender.
Serve with strips of wholemeal pitta bread and raw carrot sticks.
Poached salmon served with new potatoes and avocado salsa (diced red onion, tomato, mango, avocado, fresh coriander and lemon juice)
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