What does the degree of hydrolysis mean?

The degree of hydrolysis is defined as the percentage of the number of peptide bonds in a protein which have been cleaved during hydrolysis. Upon enzymatic hydrolysis of the peptide bonds in a protein, new amino groups are formed, one amino group for each broken peptide bond. The amount of newly formed amino groups causes a linear increase in amino nitrogen. This amino nitrogen can be determined by formol titration. In the calculation of the degree of hydrolysis, the increase of amino nitrogen, corrected for the total number of peptide bonds available for cleavage in the protein is calculated.