Influence of milk type, fat reduction and ripening time on the proteolysis, textural properties and volatile compounds in acid- and heat-coagulated Circassian cheese

The objectives of this study were to determine the effect of milk type, fat reduction, and ripening time on some quality characteristics of acid-and heat-coagulated Circassian cheese. For this purpose, Cheeses were produced using reduced- and full-fat ewe’s and cow’s milk, and analyzed for nitrogen fractions, textural properties, and volatile organic compounds (VOCs) during ripening. Proteolysis and texture were significantly influenced by all three factors. Cow’s and ewe’s milk cheeses showed similar proteolysis, but full-fat cheeses had higher proteolysis levels than reduced-fat ones. Ewes’ milk cheese was firmer, harder to chew, gummier, and more adhesive than cows’ milk counterpart. Moreover, full-fat milk cheese was softer, lower to chew, less gummy, and had a more lubricant texture than its reduced-fat milk counterpart. Fat reduction had no significant effect on VOCs, nor did the type of milk or ripening period, as supported by cluster analysis of the heatmap. The concentrations of hydrocarbons in fresh samples were higher than in all other groups, while acids were quantitatively the most abundant chemical family in mature cheeses. In the PCA score plot, reduced- and full-fat cheeses produced from ewes’ (ERF and EFF) and cows’ (CRF and CFF) milk were positioned in different groups in terms of VOCs distributions.