PREPARATION AND CHARACTERIZATION OF CHICKEN
EGG WHITE HYDROLYSATE
Blaž Cigić and Marija
Zelenik-Blatnik
Department of Food Science and Technology,
Biotechnical Faculty, Jamova 101, 1000
Abstract
Albumen of
freshly laid chicken eggs was thermally treated at various pH values in order
to find optimal conditions for subsequent enzymatic hydrolysis with Alcalase (Subtilisin Carlsberg).
Alkalisation to pH 10 followed by 30 minutes heating between 75 °C and 80 °C resulted in irreversible denaturation of Alcalase
inhibitors and formation of soluble aggregates of denatured proteins. Denatured albumen was most effectively
hydrolysed at
60 °C and pH 8.5. Hydrolysis rate
between pH 7 and pH 9 was relatively high and therefore hydrolysis without pH
regulation was performed. Bitter peptides, which were formed as a result of Alcalase hydrolysis, were degraded with Flavourzyme,
a mixture of fungal exopeptidases and endopeptidases. Degree of hydrolysis over 30 and high yield
of peptides soluble over a wide pH range were obtained by combination of
peptidases. Hydrolysate, which contained substantial
amount of dipeptides and tripeptides
was only moderately bitter and had an overall acceptable flavour.
Key words: egg white, hydrolysate,
hydrolysis, Flavourzyme, Alcalase,
peptides, inhibitor