The chicken egg is one of the finest
foods, offering man almost complete balance of essential nutrients with
proteins, vitamins, minerals and fatty acids of great biological value
(Brugalli et al., 1998) in addition
to being one of the foods of lowest cost. It increase the consumption of food
of high nutritional value for the low income population (Pascoal et al., 2008, Menezes, 2009).
In Nigeria, because refrigeration is
not mandatory, commercial eggs are packed from the moment they are laid and
stay until the final distribution at room temperature, and in some cases,
refrigerated only in the home of consumers. Although the Nigerian law
determines minimum internal traits, only the weight and characteristics of the
shell have been considered (Brasil, 1997).
The use of Haugh unit has been
accepted as a measure of the quality of the albumen in various studies of egg
quality. The Haugh unit value of fresh eggs decreases with increasing age of
the hen (Silverside et al., 1993, Ramos
et al., 2008) and the albumen height
decreases as birds ages (Carvalho et al.,
2003). According to Sauveur (1993) and Santos
(1993), temperature and storage time negatively influence the quality of eggs
and significantly reduce the Haugh unit because of the continuous loss of carbon
dioxide.
Davis and Stephenson (1991), Morais et al., (1997), Leandro et al.,
(2005) and (Menezes et al., 2009)
reported that the temperature and relative humidity are the most important
factors that affect egg quality during storage. Barbosa et al., (2004), evaluating the effect of temperature (Ambient and
refrigerated) and storage time (0,7,14,21,28 and 35) on egg quality, verified
that the increase of storage time caused reduction in Haugh unit and egg
weight. They also reported that the storage time affected the egg quality,
inserting a negative influence on the Haugh unit.