Titration – a rapid method for the determination of proteolysis in cheese

Abstract

Titration is an old method used for the determination of acidic and basic groups of a molecule. Several metabolic end-products in cheese are compounds with acidic or basic groups, e.g. propionic, acetic and lactic acids, amino acids, amines and ammonia. A number of colorimetric and fluorometric methods have been used to study proteolysis in cheese; some are time-consuming with several steps, and certain of the reagents are hazardous.We have used acid-base titration for analysis of the products of proteolysis in Swiss-type cheese. The titration system was that originally developed for use in silage analysis (Moisio & Heikonen, 1989) and applied to cheese it has proved to be useful, easy and rapid with an accuracy similar to that achieved by colorimetry.

Cheese: Methods of Chemical Analysis

“…The buffering capacity of cheese increases during ripening owing to the formation of ammonia, amino and imino groups. This principle was used by Ollikainen 74 to assess proteolysis in cheese; it was claimed that the method is rapid and convenient and as accurate as colorimetric methods.…”

“…Reaction with p-benzoquinone provides the basis of a colorimetric procedure for assaying peptide bond cleavage. The method of Lorenz 75 was compared by Ollikainen 74 with the above titrimetric procedure.…”

Buffering capacity of dairy products

“…An increase in buffering capacity has also been reported during the ripening of Swiss-type cheese. This increase involves two buffering areas in pH ranges 2-5 and 8.5-10.5 when cheese is titrated with base after its acidification (Ollikainen, 1990). The author attributed the first area to the carboxyl group buffering capacity of acidic amino acids and lactic, acetic and propionic acids.…”

Chemical methods for the characterization of proteolysis in cheese during ripening

“…This principle was used by Ollikainen (1990) to assess proteolysis in a Swiss-type cheese; it was claimed that the method is rapid and convenient and as accurate as colorimetrie methods. Changes in the buffering capacity of Emmental around pH 9 have been attributed to proteolysis (Lucey et al, 1993).…”