Mathematical Expressions for Organic Acids in Early Ripening of a Cheddar Cheese

Cheddar cheeses were sampled at intervals during maturation and analysed for organic acids by means of ion-exchange HPLC. Regression modelling was used to define the patterns of the organic acids by mathematical equations. The equations may form the basis for estimation of the organic acids during maturation of similar Cheddar cheeses and form part of a model to predict the organic acid concentrations without the need for physical analysis or alternatively calculate the age of the cheese using organic acid data as variable. Marked variation occurred amongst the first five sampling intervals ascribed to, amongst others, the processing steps between the salted curd and day 1 of maturation. Malic, lactic, pyruvic and citric acids increased during maturation at different trends and rates. The concentrations of acetic, propionic and isovaleric acids dropped rapidly followed by an increase. A similar trend was noted with butyric acid, although less substantial. n -Valeric acid decreased during the maturation period to almost undetectable quantities. The patterns followed by a number of acids corresponded fundamentally with reports in literature, although a degree of variation was noted which may be ascribed to the individuality of the tested cheese.