36. Cheese-Ripening Studies: Nitrogen Distribution in Kingston Cheese-Ripening

Abstract

A study has been made of the nitrogen distribution in Kingston cheese, over a ripening period of 98 days. For the determinations, methods evolved and employed by Orla-Jensen, Barthel and others have been drawn upon. In addition, a departure has been made in applying to this study the method developed by Wasteneys and Borsook for the fractional analysis of incomplete protein hydrolysates.Determinations were carried out on cheese of the same “make” from the day of making to the 98th day of ripening at intervals denned and recorded in the tables and figures.Results obtained when employing the methods of Orla-Jensen and of Barthel have been complemented by the application of the Wasteneys and Borsook method, which defines the nature and the amount of various protein decomposition fractions (proteose, peptone and sub-peptone) formed as the ripening of the cheese proceeds.Particularly striking is the finding that the difference in the results of the amide nitrogen determinations and the amino nitrogen determinations can be explained when interpreted in the light of data secured by the application of the method of Wasteneys and Borsook. The amide nitrogen curve has been found to coincide with the sub-peptone nitrogen curve, and the amino nitrogen curve to superimpose itself upon the curve depicting the sum of the subpeptone nitrogen and the peptone nitrogen.The results of our study, subject to qualification as further data on the nature of specific enzymes may appear, suggest that after the first few hours of ripening the proteolytic breakdown in the ripening of Kingston cheese is of an associative peptic-tryptic-like nature.