An Extensive Description of the Peptidomic Repertoire of the Hen Egg Yolk Plasma

Hen
egg is a raw material widely used for the preparation of food, 
pharmaceutical and cosmetoceutical products. Dedicated proteomic studies
were accomplished on eggshell membrane, egg white, and yolk, identifying
the most abundant proteins. No similar peptidomic studies have been
performed so far. Only preliminary investigations on bioactive peptides
in egg fractions and digestates were accomplished through functional
screening assays, characterizing antioxidant, antibacterial, antiviral,
immunomodulatory, and antihypertensive preparations and isolated components.
This study fills this gap and provides a comprehensive picture of
the peptides present in the yolk plasma of different hen egg types
after 24 and 264 h of laying, taking advantage of a procedure based
on a two-step fractionation followed by combined MALDI-TOF-TOF-MS-
and nanoLC-ESI-Q-Orbitrap-MS/MS-based analysis. Six hundred and twenty-eight
peptides were characterized as deriving from the proteolytic processing
of larger protein components after the physiological action of chicken
chymotrypsin-like and pepsin-like enzymes. Structural details on their
post-translational modifications were also provided. Identified peptides
were subjected to bioinformatic analysis and further compared with
available data from the literature, ascertaining 198 peptides associable
with putative antihypertensive, antimicrobial, anticancer, antiviral,
antibiofilm, anorectic, calcium-binding, and anti-inflammatory activities.
This analysis was often confirmative of previous experimental evidence
on functional properties of unfractionated preparations or isolated
molecules. These results further emphasize the bioactive action of
yolk-derived peptides as related to egg consumption, and the potential
use of these molecules as additive ingredients in the preparation
of functional foods and cosmetics.