Tuesday, 28 July 2009
Eggs are one of the most common and versatile cooking ingredients. The most commonly used are poultry eggs from chicken, followed by duck, goose and quail. Other more exotic eggs from the bird family include ostrich, gull, guinea fowl, pheasant and emu eggs.
Chicken eggs (hereby referred to as eggs) are widely used in many types of dishes, both sweet and savoury. Eggs can be pickled, hard-boiled, soft-boiled, scrambled, fried and refrigerated. They can also be eaten raw, though this is not recommended for people who may be especially susceptible to salmonella, such as the elderly, infirm or pregnant women. In addition, the protein in raw eggs is only 51 per cent bio-available, whereas that of a cooked egg is nearer 91 per cent bio-available; meaning the protein of cooked eggs is nearly twice as absorbable as the protein.
Eggs have been a valuable source of food since prehistory, when our ancestors were hunter gatherers. In Thebes Egypt, the tomb of Haremhab, built about 1420 BC, shows a depiction of a man carrying bowls of ostrich eggs and other large eggs as offerings. In ancient Rome, eggs were preserved and meals often started with an egg course. In the middle ages, eggs were forbidden during Lent because of their richness.
Eggs supply essential amino acids for humans, and provide 11 different vitamins and minerals, including vitamin A, D, E, riboflavin, folic acid, vitamin B12, choline, iron, calcium, phosphorus and potassium. They are also an inexpensive single-food source of high quality protein, healthy fats (including omega-3) and important antioxidants.
All of the egg's vitamin A, D and E is in the egg yolk. The egg is one of the few foods which naturally contain Vitamin D. A large egg yolk contains approximately 60 Calories (250 kilojoules); the egg white contains about 15 Calories (60 kilojoules). A large yolk contains more than two-thirds of the recommended daily intake of 300 mg of cholesterol (although one study indicates that the human body may not absorb much cholesterol from eggs). The yolk makes up about 33 per cent of the liquid weight of the egg. It contains all of the fat, slightly less than half of the protein and most of the other nutrients. It also contains all of the choline, and one yolk contains approximately half of the recommended daily intake. Choline is an important nutrient for development of the brain, and is said to be important for pregnant and nursing women to ensure healthy fetal brain development.
Recent research shows eating eggs has very little, if any, effect on blood cholesterol levels with the real culprit being saturated fat. In addition, chicken eggs that are high in Omega 3 fatty acids have come on the market. These eggs are made by feeding laying hens a diet containing polyunsaturated fats and kelp meal. Nutrition information on the packaging is different for each of the brands.
In Australia, the Australian Egg Corporation Limited (click HERE for the website) defines the sizes of eggs sold in Australia. The following table shows Australian egg sizes.
According to the Australian Bureau of Statistics (or the ABS), Australia produced 236.4 million eggs (from 440 producers) in 2006/07. Average retail prices for one dozen eggs (March quarter, 2008) sold in Australia is $4.51. A breakdown of the grocery/retail production share of these eggs is presented below.
Eggs should be considered in a similar way as other protein-rich foods and included as part of a varied diet that's low in saturated fat and contains a variety of cardio-protective foods (such as fish, wholegrains, fruit, vegetables, legumes and nuts).
There is little research to guide recommendations for egg consumption for people at high risk of heart disease (e.g. with diabetes or high cholesterol). However, prudent advice is that the inclusion of eggs in the context of a diet low in saturated fat, and containing known cardio-protective foods, is not associated with increased risk.
As eggs provide a great source of high quality protein, a relatively low amount of kilojoules and 11 different vitamins and minerals, they are an excellent inclusion in a healthy, well balanced diet:
* Boil eggs and pack for lunch with wholegrain bread and salad.
* Scramble eggs with grated or finely chopped vegetables and serve with ham, tomato and mushrooms for a great Sunday morning ‘pick-me-up.'
* Mash boiled egg with canned salmon and ricotta cheese for a high calcium sandwich filling or as a topping for wholegrain crackers.
* Mix beaten eggs with grated reduced fat cheese, cracked pepper and parsley and stir through cooked wholemeal pasta for a quick and easy dinner or lunch. Serve with a green side salad.
* Make a healthy fried rice by mixing cooked, chopped vegetables, ham, and chopped boiled egg with cooked rice. Stir fry in sesame oil, add a splash of soy sauce and cook until heated through.
Source: Wikipedia, Australian Egg Corporation, Australian Bureau of Statistics, AC Nielsen and Eggs.Org.Au