Quality evaluation and discrimination of semi-hard and hard cheeses from the Marche region (Central Italy) using chemometric tools

Twenty-nine semi-hard and hard cheeses from the Marche region (Central Italy) made from either raw or pasteurised ewes', goats', and cows' or a blend of ewes' and cows' milk were analysed for pH, water activity, gross composition, bacterial ecology, and volatile compound profile. Two chemometric tools were used to analyse the available data: principal component analysis (PCA) for preliminary exploratory data analysis, and partial least square discriminant analysis (PLS-DA) for cheese classification by type of milk, treatment (raw versus pasteurised), and origin. PCA and PLS-DA of the outcomes allowed the cheeses to be grouped according to type of milk (cows' versus ewes' or goats') and treatment (raw versus pasteurised), whereas no clear separation between Protected Designation of Origin, niche, and speciality cheeses from similar productions or industrial competitors was attainable. Among the variables, the free fatty acid profile showed a high potential for the discrimination of goats' milk cheeses.