When producing hydrolyzed proteins, it is important to determine the degree
of hydrolysis (DH). The trinitro-benzene-sulfonic acid (TNBS) method is we
ll established with regard to enzymatic hydrolysis. However, this method is
laborious, cannot be used to follow a hydrolysis reaction continuously, an
d includes hazardous and unstable chemicals. This paper describes a method
based on the reaction of primary amino groups with omicron -phthaldialdehyd
e (OPA). The conclusion is that the OPA method of analyzing the DH of prote
in hydrolyses is more accurate, is easier and faster to carry out, has a br
oader application range, and is environmentally safer than the TNBS method.