Improved Method for Determining Food Protein Degree of Hydrolysis

TLDR

Determining the degree of hydrolysis (DH) is essential in protein hydrolysis, yet the standard TNBS method is laborious, unsuitable for continuous monitoring, and relies on hazardous chemicals. The study proposes a new DH determination method using the reaction of primary amino groups with o‑phthaldialdehyde (OPA). The OPA assay measures DH by reacting primary amino groups with o‑phthaldialdehyde, providing a rapid and continuous readout. The OPA method proved more accurate, faster, easier, broadly applicable, and environmentally safer than the TNBS method.

Abstract

ABSTRACT When producing hydrolyzed proteins, it is important to determine the degree of hydrolysis (DH). The trinitro‐benzene‐sulfonic acid (TNBS) method is well established with regard to enzymatic hydrolysis. However, this method is laborious, cannot be used to follow a hydrolysis reaction continuously, and includes hazardous and unstable chemicals. This paper describes a method based on the reaction of primary amino groups with o‐phthaldialdehyde (OPA). The conclusion is that the OPA method of analyzing the DH of protein hydrolyses is more accurate, is easier and faster to carry out, has a broader application range, and is environmentally safer than the TNBS method.