Eggs: what makes them so special?

Eggs are a healthy and balanced food. They have recently been shown to be a “fat-free” food, suitable for those wishing to reduce the percentage of fat in their diet. The egg has always been considered an interesting food both from the nutritional point of view, as a source of protein, and from an economic point of view. They’re great in so many ways: inexpensive, easy to prepare and cook quickly.On the market it is possible to find eggs from hens, but also from quail, goose, duck and ostrich. There are great differences between the hen’s egg and that of ostrich or quail, not only in weight or color, but also in composition.

Organoleptic properties of the hen’s egg

In a hen’s egg of about 60 grams there are at least 8 grams of proteins, vitamins of the B group, sodium, potassium, iron and phosphorus; the most marginal part of the egg is represented by fats, while the calories are really few. An average hen egg contains in fact only 78 kcal, but its high protein content is 6.5 grams, or 13% of an adult’s daily requirement. According to the regulations on labelling, eggs qualify as a source of vitamin A and B12; they are also rich in vitamin D and contain choline, phosphorus, selenium, riboflavin, folic acid, biotin and iodine. The yolk is the constituent of the richest egg in nutrients. In addition to water, lipids and proteins, it also contains moderate amounts of iron, phosphorus and B vitamins. It does not contain vitamin C, which is not an essential nutrient for most animals.

The albumen, however, also known as egg white, occupies about 60% of the volume of the egg and is a protective barrier against the yolk, acting as a natural preservative that fights against bacteria that can contaminate the yolk, compromising the development of the embryo. Chemically it is mainly composed of water (88.5%), proteins (10.5%), mineral salts (magnesium, sodium and potassium), B vitamins and free glucose. Unlike the yolk, it does not contain lipids. The porous structure of the shell, permeable to gases and water vapour, essentially consists of calcium carbonate.

 

The supply chain in Italy

In Italy, around 12 billion eggs are produced each year (95% self-sufficiency) coming mainly from Emilia Romagna, Veneto and Lombardy regions. Consumption is 220 eggs/person/year.
The cost of Community production is between 80 and 90 cents/kg of eggs. The supply chain starts from breeding stock – hatchery, pullet phase – laying hen rearing – selection/shelling of eggs and subsequent marketing of the product. Most of the Italian production takes place in vertically organized farms. The advantage of having highly skilled technicians, of avoiding the splitting of production and, finally, of providing a good homogeneity are some of the benefits provided by this type of organization.

Classification of eggs, traceability and packaging

The eggs for consumption are classified in XL (over 73 grams), L (from 63 to 73 grams), M (from 63 to 53 grams), and S (less than 53 grams). The packaging has the stamp of the laying hen establishment, the quality category (fresh eggs are only A), the weight and the term of preservation, as well as the method of production (free range, organic, etc.).

 The commercial classification of eggs is carried out at the time of packaging, which takes place only at plants specifically authorized by law to package them. The eggs on the market are sold in packages closed by a band-shaped label; normally there are packs of 4, 6, 12 eggs, but you can also find packs of 20 or 30 pieces, intended for communities, food businesses such as restaurants, canteens, etc. Eggs can also be sold loose, and then re-packed, but only by authorized centers.

A different fate concerns the eggs not in shell, which pass through a pasteurization and are then divided into successive stages of production.At the packing centers, the eggs are subjected to the candling process: an operator, with the aid of a light source, observes the eggs that run along a conveyor belt in backlight. In this way, it’s possible to look at egg’ contents in transparency, highlighting possible cracks in the shell, blood stains, presence of inclusions, arrangement and size of the yolk and the tube, etc. Defective eggs are declassed and destined for processing in the food industry, depending on the type of defect. European legislation distinguishes eggs in quality and weight categories. The quality categories are: the “A” category, intended for human consumption. Within this category the eggs can be distinguished in: “very fresh” (if packaged within 24 hours of deposition and sold within 7 days of packaging) and fresh (if packaged within 48 hours of deposition).

The “B” category eggs, on the other hand, are destined for processing (food and non food industries) and are placed on the market with a red label or strip. After purchase, the eggs should be placed in the refrigerator, to maintain the characteristics related to freshness for a time longer than storage at room temperature. During egg storage, the barriers that oppose microbial contamination lose their effectiveness over time as the temperature will be higher and it becomes much easier for bacteria to enter the egg. For this reason, it is very important that the preservation of eggs for direct consumption is carried out at low temperature (in normal household refrigerators at temperatures between 4 and 8 °C) and for short times. In fact, the refrigeration temperatures slow down the aging process of the egg.