Methodology for Determining Degree of Hydrolysis of Proteins in Hydrolysates: A Review

Degree of hydrolysis (DH) is defined as the proportion of cleaved peptide bonds in a protein hydrolysate. Several methods exist for determining DH; the most commonly used of these include the pH-stat, trinitrobenzenesulfonic acid (TNBS), o-phthaldialdehyde (OPA), trichloroacetic acid soluble nitroge...

Full description

Saved in:
Bibliographic Details
Published in:Journal of AOAC International 2010-09, Vol.93 (5), p.1515-1522
Main Author: RUTHERFURD, Shane M
Format: Article
Language:English
Subjects:
Amino Acids - analysis
Biological and medical sciences
Food industries
Fundamental and applied biological sciences. Psychology
Health aspects
Hydrogen-Ion Concentration
Hydrolysis
o-Phthalaldehyde - chemistry
Peptides
Physiological aspects
Protein hydrolysates
Protein Hydrolysates - analysis
Proteins - chemistry
Trinitrobenzenesulfonic Acid - chemistry
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Degree of hydrolysis (DH) is defined as the proportion of cleaved peptide bonds in a protein hydrolysate. Several methods exist for determining DH; the most commonly used of these include the pH-stat, trinitrobenzenesulfonic acid (TNBS), o-phthaldialdehyde (OPA), trichloroacetic acid soluble nitrogen (SN-TCA), and formol titration methods. The pH-stat method is based on the number of protons released during hydrolysis; the TNBS, OPA, and formol titration methods are based on the measurement of amino groups generated from hydrolysis. The SN-TCA method measures the amount of TCA-soluble nitrogen, rather than DH. The pH-stat is the simplest and most commonly used method, but does not determine peptide bonds directly. In addition, the accuracy of the method depends on the type of hydrolytic enzymes used, the size of the hydrolyzed peptides, and the reaction temperature. Generally, the TNBS and OPA methods compare well and do directly determine DH. However, the assumption that the response factor for all derivatized N-terminal amino acids is similar may lead to inaccuracies. In conclusion, there is no consensus as to the best method for determining the DH of protein hydrolysates; consequently, there is a need for a standardized approach if interstudy comparisons are to be made.
ISSN:1060-3271
1944-7922
DOI:10.1093/jaoac/93.5.1515