EGGS
History
Because birds preceded man in the evolutionary chain, both eggs and birds have existed longer than historians. East Indian history indicates that wild jungle fowl were domesticated as early as 3200 BC. Historians also note that the fowl were eaten more often than the eggs, since the eggs were saved to hatch to keep the fowl in supply. Egyptian and Chinese records show that fowl were laying eggs for man in 1400 BC. Chinese described fowl as “the domestic animal who knows time”, probably due to the dependability of the rooster’s early morning call and the regularity of the hen’s egg production.
Although there is some evidence of native fowl in the Americas prior to his arrival, it is believed that Columbus’ ships carried to this country the first of the chickens related to those now in egg production. These strains originated in Asia.
While the fowl referred to in the earliest histories could include a vast assortment of avian representatives, most people of the world eat, and all information here refers to, the egg of the chicken (Gallus domesticas). Nearly 200 breeds and varieties of chickens have been established worldwide, but only a few are economically important as egg producers. Most laying hens in the U.S. are Single-Comb White Leghorns.
Ancient Times
East Indian history indicates that wild fowl were domesticated as early as 3200 B.C. Egyptian and Chinese records show that fowl were laying eggs for man in 1400 B.C. and Europe has had domesticated hens since 600 B.C. While there’s evidence of native fowl in the Americas prior to Columbus’ arrival, it’s believed that on his second trip, he carried the first chickens related to those now in egg production.
Nearly 200 breeds and varieties of chickens have been established worldwide. Most laying hens in the U.S. are Single-Comb White Leghorns.
The Early 1900s
Egg farms were still mostly backyard systems that supplied families with eggs. Any extras were sold at the local farmers’ markets. As selling eggs became profitable, some farms started building up flocks of about 400 hens. The hens roamed around outside with a coop for roosting.
The 1920s
Living outside presented some problems, mainly with weather and predators. Diseases were also a problem and selective breeding helped to cultivate healthy flocks. Hatcheries chose the strongest, healthiest birds and passed along favorable genetic factors, such as disease resistance. Special medicines were developed to help combat parasites, such as leg mites.
While these advances helped, the hens were laying only about 150 eggs a year and had a mortality rate of about 40%.
The 1930s
Research on moving hens to indoor living showed many benefits. While expensive, specialized henhouses resulted in much healthier birds. Hens weren’t exposed to predators and the elements. And indoor housing also helped to prevent parasite infestations and reduce the spread of diseases from outside carriers, including rodents and even humans. Better feeding practices also improved hen health and egg productivity.
These changes reduced hen mortality to 18% a year. But problems remained, including sanitation, waste control and the pecking order.
The 1940s
In the late 1940s, some poultry researchers had favorable results with raised wire-floor housing for hens. The separated wire housing was quickly adopted in California. Sanitation improved as neither hens nor eggs came into contact with waste and waste removal was easier. Feeding became more uniform as the more timid hens were able to eat and drink as much as they required, like the more aggressive hens.
The research on caging proved itself. A healthy hen will lay a lot of eggs. California hens each produced about 250 eggs per year and mortality dropped to 5%. Based on this, more farms across the country built new facilities with the cage style of housing.
The 1950's
The caging system also lent itself to increased automation, which was needed to handle the increased output of eggs from the hens. Conveyor belts were added to the hen house to collect the eggs as soon as they were laid and carry them to the washers.
The 1960's
By the early 1960s, improved technology and the development of sophisticated mechanical equipment were responsible for a shift to larger commercial operations.
Improving the health of hens through more protective housing and better feeding facilities led to more eggs which led to increased automation to handle the eggs. With increased automation, labor costs were reduced, providing a lower cost to the consumer. In addition to much improved hen health, equal-opportunity feeding also made the nutrient quality of eggs more uniform.
Modern Day Egg Production
Each of the roughly 300 million laying birds in the U.S. produces from 250 to 300 eggs a year. In total, the U.S. produces about 75 billion eggs a year, about 10% of the world supply. About 60% of the eggs produced are used by consumers, about 9% are used by the foodservice industry. The rest are turned into egg products which are used mostly by foodservice operators (restaurants) and by food manufacturers to make foods like mayonnaise and cake mixes.
TYPES OF EGGS
Standard White Eggs
These eggs come from white hens that are typically raised in conventional housing systems. Conventional housing has been the standard for decades, but the Alberta egg industry has begun to transition away from conventional housing systems.
Standard Brown Eggs
These eggs come from brown hens that are typically raised in conventional housing systems. Conventional housing has been the standard for decades, but the Alberta egg industry has begun to transition away from conventional housing systems.
Furnished / Enriched / Nest-Laid Eggs
These eggs come from hens that are raised in furnished housing systems. Furnished housing provides more space (both floor space and height) for the hens to move around, while also providing a variety of enrichments, which allow the hens to express more natural behaviours. Enrichments include nesting boxes, perches, scratch pads and dust baths.
Free-Run Eggs
These eggs come from hens that are raised in free-run (barn or aviary) housing systems. Free-run systems allow the hens to roam freely within an enclosed barn, while also providing a variety of enrichments such as nesting boxes and perches.
Free-Range Eggs
These eggs come from hens that are raised in free-run (barn or aviary) housing systems, which also provide access to outdoor runs (when weather permits).
Organic Eggs
These eggs come from hens that are raised in free-range housing systems. The hens are only provided feed that has been certified organic, which means that it only contains ingredients that were grown without pesticides, herbicides or commercial fertilizer. Look for a certified organic symbol on the egg carton.
Omega-3 Eggs
These eggs come from hens that were provided feed containing extra flax (up to 10-20%). As a result, the eggs laid by these hens contain more Omega-3 fatty acids.
Vitamin-Enhanced Eggs
These eggs come from hens that were provided feed that was nutritionally enhanced to include higher levels of certain vitamins (ie: Vitamin D or Vitamin E). As a result, the eggs laid by these hens contain corresponding higher amounts of the particular vitamin(s).
Vegetarian Eggs
These eggs come from hens that were provided feed containing only plant-based ingredients.
Processed Eggs
Liquid, frozen and dried egg products come from eggs that were broken by special egg breaking machines, and then pasteurized. They often contain added ingredients (ie: preservatives, flavouring or colouring) and this process allows for special formulations (ie: egg whites only).
NUTRITIONS
Eggs are a very good source of inexpensive, high quality protein. More than half the protein of an egg is found in the egg white along with vitamin B2 and lower amounts of fat and cholesterol than the yolk. The whites are rich sources of selenium, vitamin D, B6, B12 and minerals such as zinc, iron and copper. Egg yolks contain more calories and fat. They are the source of cholesterol, fat soluble vitamins A, D, E and K and lecithin - the compound that enables emulsification in recipes such as hollandaise or mayonnaise.
Some brands of egg now contain omega-3 fatty acids, depending on what the chickens have been fed (always check the box). Eggs are regarded a 'complete' source of protein as they contain all eight essential amino acids; the ones we cannot synthesise in our bodies and must obtain from our diet.
In one whole egg there are
78 caloreis
6,3 gr protein
5,3 gr fat
212 mg colestrol
Source
https://www.incredibleegg.org/egg-nutrition/#history-of-the-egg
https://www.livescience.com/50834-eggs-nutrition-facts.html
http://eggs.ab.ca/eggs/types-of-eggs/
https://www.bbcgoodfood.com/howto/guide/ingredient-focus-eggs?_e_pi_=7%252CPAGE_ID10%252C5647624123
Komentar
Posting Komentar