Application of the enzymatic methods to the determination of contaminated yolk in egg white

Abstract

Two enzymatic methods were applied for the determination of contaminated yolk in egg white liquid. Phospholipase D from Streptomyces species in combination with choline oxidase from Arthrobacter species (the DAOS method), and glycerol oxidase from Aspergillus japonicus in combination with lipoprotein lipase (the GlyOD method) were used for this purpose. These methods have been adapted for determining small quantities of yolk in egg white, and the results correlated well with those obtained by the conventional monomolecular surface film method. The GlyOD method was superior to DAOS method relative to the standard deviation of the value. The former method affords a one-step procedure using a single color reagent and, therefore, provides a simple, rapid and precise method for routine test as a quality control in egg processing.