1. Aim Calculation of Haugh’s unit of egg
The Haugh unit is a measure of egg protein quality based on the height of its egg white
(albumen). This is the logarithm of the height of the inner thick albumen adjusted for egg weight
(Haugh, 1937). The test was introduced by Raymond Haugh in 1937 and is an important industry measure
of egg quality next to other measures such as shell thickness and strength.
On storage the integrity of albumin structure is lost; as a result albumin spreads thinly when broken
on a cooking surface. Egg weight, albumen and yolk height, Haugh unit, albumen and yolk indices
decreased with increase in storage time while albumen and yolk width increased. Egg length and width were
not affected by storage time and method. The quality of egg albumin is measured by measuring Albumin
index, Haugh’s unit
The higher value of HU corresponds to better quality of eggs if other characteristics are good. H.U
varies with storage – 82 at farm; 77 for whole sale; 60 for retail. For an egg of poor quality H.U ranges from
36-60 while for a egg of good quality HU is 72.
1. Tripod micrometer
2. weighing balance
1. Take a sample (egg)
2. egg is weighed
3. after that egg is broken onto a flat surface (breakout method), and a micrometer used to determine
the height of the thick albumen (egg white) that immediately surrounds the yolk.
4. The height, correlated with the weight, determines the Haugh unit, or HU, rating.
The higher the number, the better the quality of the egg (fresher, higher quality eggs have thicker
whites). Although the measurement determines the protein content and freshness of the egg, it does not
measure other important nutrient contents such as the micronutrient or vitamins present in the egg.
The formula for calculating the Haugh unit is:
• HU = Haugh unit
• h = observed height of the albumen in millimeters
• w = weight of egg in grams
• H.U is the function of height of thick albumin and weight of the egg. Measurement of height of thick
albumin is done by using micrometer.
2. Haugh Unit rating Quality of eggs
90 and above Excellent
80 - 89 Very good
70 - 79 Acceptable
65 - 69 Fair
60 - 64 Consumer resistance point*
55 - 59 Poor
50 and below Unacceptable