QUALITY OF WHITE EGG
Factors Influencing Egg White Quality
When a fresh egg is cracked onto a surface, we distinguish two portions of egg white:
- The thick albumen, which supports the yolk: a denser, gelatinous layer resulting from the bonding of proteins, ovomucin, and lysozyme.
- The thin albumen, the more fluid and watery layer that spreads over the surface.
The amount of thick albumen, its thickness, and consistency are important indicators of egg quality and freshness. The Haugh Unit (HU) is used to numerically express these characteristics. It is a numerical value ranging from 0 to 100, which is the result of the ratio between the height of the thick albumen and the weight of the egg. A lower HU value indicates poorer egg quality.
LIQUEFACTION OF THE ALBUMEN
During the storage of eggs, deterioration involves the increase in the size of the air cell, lipid peroxidation, and decrease in consistency.
During egg storage, water and carbon dioxide are released through the egg’s pores. This release leads to an increase in the pH of the albumen, which has a negative effect on the protein bonds that give consistency to the thick albumen, making it more liquid. Albumen liquefaction is a natural process that increases with the aging of the product; however, it is well known that factors such as animal genetics, health status, environmental conditions, feed composition, and water potability also negatively affect it.
To improve albumen quality and address the natural deterioration of the egg, various nutritional strategies have been suggested over time. Manipulating protein balance and acid-base balance appears to be the most effective approach, but proper supplementation of trace elements and antioxidant substances has also proven effective.
SUPPLEMENTATION OF TRACE ELEMENTS AND ANTIOXIDANT SUBSTANCES
Increased oxidative stress, such as during heat stress or aging, significantly increases the production of free radicals and worsens the quality of the eggs produced. In cases of increased oxidative stress, dietary selenium supplementation meets the increased need for the production of selenoproteins, which are components of antioxidant enzymes such as peroxidases. To enhance these mechanisms, the addition of antioxidant substances such as vitamin E, vitamin C, and natural phytocomplexes can also be beneficial. Additionally, the intake of zinc and manganese, both in organic and inorganic forms, has been shown to support the body’s antioxidant mechanisms and improve shell resistance. Supplementing selenium, zinc, and manganese in the diet also increases the concentration of these elements within the egg, helping to improve its quality by counteracting common processes that degrade it.
TECNO EGG FRESH
Tecno Egg Fresh contains all the aforementioned components, and its inclusion in the diet, especially during times of increased oxidative stress when albumen or egg quality declines, can provide support for animal metabolism.
MANIPULATION OF THE ACID-BASE BALANCE
Especially during the summer months, the heat stress on animals, along with difficulties in maintaining optimal egg storage conditions, significantly accelerates albumen liquefaction.
Factors positively influencing quality and limiting liquefaction include the acidification of the animal’s water and diet.
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| Fig.1 Influence of water acidification, diet, and environmental temperatures on albumen height measured in mm | Fig.2 Influence of water acidification, diet, and environmental temperatures on pH |
Studies on the effects of pH on albumen quality, whether diets are supplemented with organic acids or not, are very encouraging.
Acidifying the diet, along with acidifying the water, especially during hot periods, positively influences albumen quality, resulting in higher HU scores.
REFERENCES
- Dunn – “Poultry breeding for egg quality: traditional and modern genetic approaches: Improving the Safety and Quality of Eggs and Egg Products: Egg Chemistry, Production and Consumption”, 2011
- F. G. Silversides and K. Budgell – “The Relationships Among Measures of Egg Albumen Height, pH, and Whipping Volume”
- M. S. Rahman, M. A. R. Howlider, M. Mahiuddin, and M. M. Rahman – “Effect Of Supplementation Of Organic Acids On Laying Performance, Body Fatness And Egg Quality Of Hens”
- Pasquoal Carrazzoni de Menezes; Evilda Rodrigues de Lima; Juliana Pinto de Medeiros; Wanessa Noadya Ketruy de Oliveira; Joaquim Evêncio-Neto – “Egg quality of laying hens in different conditions of storage, ages and housing densities”
- K.C. Williams – “Some factors affecting albumen quality with particular reference to Haugh unit score”
