19 Eggs and Egg ProductsProcessing

Eggs play an important role in the human diet and nutrition as an affordable nutrient-rich food commodity that contains highly digestible proteins, lipids, minerals, and vitamins (Fisinin et al., 2008). Over the past 35 years, global egg production has grown 203.2%, due to a rapidly increasing demand for proteins in the developing world (Windhorst, 2007). In 1970, the US was the greatest egg producer in the world, contributing over 20% of the global egg production (Windhorst, 2007). However, the US egg production has changed little since then, contributing 9% in 2005. During the same period, China has increased egg production over 20 times, contributing 41.1% of worldwide egg production in 2005. The major egg-producing countries are China, US, India, Japan, and Mexico. The majority of egg consumption in China is in the form of table eggs, as only about 1% of eggs are broken and further processed into egg products. In the US, however, about 30% of eggs are processed into various egg products (i.e. liquid, frozen, and dried egg products) for uses in the food service industry or as ingredients in various food applications. Examples of other egg products include hard-cooked chopped eggs, precooked scrambled eggs or omelets, quiches, precooked egg patties, scrambled egg mixes, and crepes (Froning, 2008). In addition to food uses, eggs also contain a range of bioactive components that can be used for improving human health and other non-food applications. Extraction and fractionation of bioactive egg components such as lysozyme, avidin, ovotransferrin, ovomucin, antibody (IgY), phospholipids and sialic acid, and development of bioactive peptides from egg proteins represent great opportunities in novel applications of egg components in the future. The objectives of this chapter are to provide an overview of egg formation, structure and chemistry, and then to introduce shell egg and broken egg processing. Perspectives on value-added egg processing for novel applications are also presented. For earlier references on egg science and processing, the reader should refer to Burley and Vadehra (1989), Stadelman and Cotterill (1995), Yamamoto et al. (1997), and Bell and Weaver (2002).