The Egg Quality Testing System on a Texture Analyser provides the tools that enable the producer and packer of poultry eggs to accurately and consistently measure the quality of their produce. They can regularly monitor a range of parameters to ensure that their eggs meet the required quality standards and that these are maintained throughout the laying period.
13 measurements in 4 minutes
✔️ Whole egg weight
✔️ Dry shell weight
✔️ Shell breaking strength
✔️ Shell deformation
✔️ Albumen height
✔️ Haugh unit calculation
✔️ Shell thickness
✔️ Vitelline membrane strength (yolk rupture)
✔️ DSM yolk colour
✔️ Yolk height, width (manual input) and index
✔️ Air cell height (manual input)
Whole egg and dry shell weight
Whole egg weight (measured to +/- 0.1g)
Egg weight is genetically linked to all three of the major components: shell, albumen and yolk. The link between egg weight and albumen weight is higher than those between egg weight and shell or yolk weight, and as egg size increases, so does the percentage of albumen.
By placing the egg in a cradle mounted to the calibration platform of the instrument the weight of the egg can be measured and recorded in g.
Dry shell weight (measured to +/-0.1g)
With storage, wet egg weight decreases causing a lower egg weight.
In order to measure the weight of the wet egg the dry shell weight can be subtracted from the original whole egg weight.
Shell breaking strength and deformation
Shell breaking strength (measured to +/- 0.1g)
Shell strength, which refers to the ability of the shell to remain sound during transit from the hen to the consumer, is economically the most important of all the egg-quality characteristics. The structural quality of the shell egg is important to the processor because eggs that are structurally sound will arrive to the consumer in the best condition. Poor shell quality will result in a greater number of cracked eggs, which will result in greater losses for the producer.
The force required to crush a shell is a measure related to shell integrity and resistance to breakage. At the point of break the force is recorded in g and used as the shell breaking strength.
Shell deformation (measured to +/-0.1mm)
At the point of breaking the compression distance is recorded. This is the degree of deformation in mm that the shell can withstand before irreversible breakage.
Shell thickness
Measured to +/-0.1mm
Shell thickness is almost entirely dependent on breed, feed and the age of the bird. As the laying period progresses, egg shells become thinner. The rate of decline in shell thickness is particularly marked in the latter half of the laying year but environmental temperature and nutritional factors also influence thickness.
A 0.25” Spherical Probe is used to approach a small section of the egg shell (broken from the shell of the egg tested with previous procedures) and measure the thickness of the shell (in mm) at the point of contact.
Albumen height and Haugh unit calculation
Egg albumen height (measured to +/-0.1mm)
The higher the albumen height, the better the albumen quality. The height can vary from as low as 1.5mm in stale eggs of poor quality to 12mm in good quality fresh eggs. Generally the younger the bird, producing newly laid eggs, the higher the albumen height.
Calculation of Haugh unit and egg classification
The Haugh Unit has been widely accepted throughout the world as the “gold standard” for quantifying the internal quality and freshness of eggs. It is the only objective measurement of “freshness” and corresponds very closely to consumer preferences.
It is a ratio calculation involving the egg weight and thick albumen height.
The formula for calculating the Haugh unit is:
Where:
• HU = Haugh unit
• h = height of the albumen in millimeters
• w = weight of egg in grams
After the egg is weighed (in the first procedure) and the shell strength determined (optional) the egg is broken onto the egg tray. The cylinder probe is positioned in a suitable location next within the thick albumen region (immediately surrounding the yolk) and the height of the albumen is measured at the point of touching the albumen surface. The values are inserted into the above formula and a Haugh rating is calculated within the software.
The Haugh unit value ranges from 0 - 130 and can be ranked as below:
• AA : 72 or more
• A : 71 - 60
• B : 59 - 31
• C : 30 or less
The higher the number, the better the quality of the egg (fresher, higher quality eggs have thicker whites). A minimum Haugh unit measurement of 60 is desirable for whole eggs sold to the domestic consumer. Most eggs leaving the farm should average between 75 and 85 Haugh units.
Vitelline membrane strength (yolk rupture), yolk height and width
Vitelline membrane strength/yolk quality (measured to +/-0.1g)
With the increase in further processing of eggs, structural integrity of the vitelline (yolk) membrane has become an increasingly important issue for the egg-breaking industry. Today, millions of kilos of liquid egg products are produced each year for use in food service, commercial egg products, and as ingredients in other food products. In the egg breaking operation, liquid egg products consist of liquid whole egg, egg yolk, or egg albumen. Egg albumen is a particularly effective foaming agent that is used in baking and in the preparation of confections. Foaming ability of the egg albumen is dependent on the quality of albumen proteins, and slight crossover contamination with yolk can alter protein functionality and reduce foaming properties of the egg albumen. Recent trends in dietary improvements have also influenced many individuals to take more proactive steps to removing the yolk from the albumen when consuming egg products. Successful separation of the egg yolk from the albumen is therefore extremely important, and the strength of the vitelline membrane, particularly its ability to withstand the breaking process, is a key factor in producing good quality egg albumen.
Vitelline membrane characteristics have been seen as not only physical factors but also as microbial quality contributors in the egg. Factors influencing vitelline membrane strength are the same factors influencing albumen quality. During storage, egg quality deterioration is a factor of time, temperature, humidity, and handling. As the egg ages, egg quality deteriorates and the rate of deterioration is increased with higher storage temperatures.
The Vitelline Membrane Strength is measured by puncturing the yolk using a spherical probe. The probe approaches the yolk and measures the force (in g) to rupture the yolk.
Yolk colour, width and index
Yolk Colour (using DSM Yolk Colour Fan)
When judging the quality of an egg, another criteria that consumers apply for freshness is the egg yolk colour. A simple but subjective method of determining this involves either the BASF Ovo-colour Fan or the DSM (formerly Roche) Yolk Colour Fan that expresses results in a 1 to 15 scale by means of visual comparison with calibrated cards in a fan. These fans consist of a range of paper blades coloured in fifteen possible outcomes of egg colour and numbered accordingly. The blades are held over the yolk and the colour of the yolk compared with the blades to find a corresponding blade of the same colour. This number is then assigned to the egg yolk.
The DSM Fan is a consistent, economical and readily available means of quantifying yolk colour and has become the preferred method in most parts of the world. DSM has studied consumer preferences in many parts of the world and found that, while preferences vary, consumers in most countries prefer an egg yolk color with a DSM Yolk Color Fan value of 12 or more.
Most egg marketing authorities require deep-yellow to orange-yellow yolk colours in the range 9 to 12 on the DSM Yolk Colour Fan although yolks of more intense colour may be required for specific markets. A wide variation in colour may normally be expected in the yolks from any flock. If a flock averages a yolk colour score of 10 on the DSM Yolk Colour Fan, two out of every three eggs laid by the flock will score between 9 and 11. Also, one egg in 20 will score less than 8, and one in 20 greater than 12.
Yolk width and index calculation
The accepted quantitative measurement of yolk shape is the yolk index. It was developed by Sharp & Powell in 1930 and was defined by them as the ratio of the height to the width of the yolk (in mm) measured when the egg is broken out on a flat surface.
Yolk index is utilized to determine the shape changes in the yolk, primarily during storage. As the egg deteriorates, the yolk index decreases.
Advantages of this system
Leads untrained operators through the test procedures easily.
Provided by quick magnetic removal and switching of test probes.
Data storage and retrieval of test files with automatic test history view.
Test procedures available in a choice of languages.
How the Egg Quality Testing System works
At the start of testing the software provides the operator with a list of parameter options from which to choose the set of tests to be performed on each egg.
Note: There is the option to manually input the colour and width of the yolk and the air cell height during the testing procedure so that they are digitally stored alongside all of the other egg testing data but the instrument does not measure these parameters.
Step-by-step software commands lead the operator through each test procedure with diagrams illustrating each test instruction clearly.
Test probes are magnetically located to enable quick removal and switching between tests.
Each test (collecting data at 400 points per second) is accurately measured. At the end of each test, or testing session of a batch, the data can be viewed and acted upon or archived.
A printable report is produced including testing statistics
Testing requirements
The Egg Quality Testing System requires a Texture Analyser with a 10kg Load Cell with Exponent Connect/Exponent Connect Lite or Exponent/Exponent Lite software, a Control Panel (for older models without keypad control on the instrument) or Touchscreen Interface.
A 2kg calibration weight is recommended for quick and easy instrument calibration and verification of accuracy.
What’s included
Egg Quality Testing System components
- Egg tray
- Egg weighing cradle
- Magnetic probe adapter
- Magnetic 25mm Cylinder Probe (P/25)
- Magnetic ¼” Spherical Probe (P/0.25S)
- Egg support Breaker
- Yolk colour fan
- Spirit level