The major driving force for the egg consumption in the United States over the past
few decades was processed egg. However, the consumption of egg through the processed
egg reached the plateau in recent years because of the imbalance in the demands between
the egg white and yolk products. The consumer demands for egg white products are very
high while those for the egg yolk, the co-product of dried egg white, are low because
of the negative perceptions on egg yolk. Two key approaches that can be used to increase
the value and use of egg yolk are: (1) developing new commodity products by fractionating
egg yolk and apply them in various food processing, and (2) separating functional
proteins and lipids from yolk and use them as is or further develop functional peptides
and functional lipids and use them as pharmaceutical, nutraceutical, and cosmeceutical
agents. These approaches can diversify the use of egg yolk, which eventually will
help increase the consumption of egg. This review (1) discusses the current use of
egg yolk products and the development of new functional commodity products from egg
yolk, (2) review the important functional components in egg yolk and overview the
current separation methods and their applications, (3) discuss the production of functional
peptides and lipids using the separated egg proteins and lipids, and (4) suggest the
future directions for the best use of egg yolk components. Development of scale-up
production methods, which is vital for the practical applications, is discussed when
appropriate.