The Application of GC–MS and Chemometrics to Categorize the Feeding Regime of Iberian Pigs in Spain

Abstract

GC–MS and chemometric analysis of subcutaneous fat has been studied to classify three different feeding regimes of Iberian pigs. Nineteen fatty acids present in 57 fat samples were identified and quantified. Principal component analysis was employed for the preliminary study of the data structure. Discriminant analysis was used to classify samples into the three categories on the basis of the fatty acid profiles. Using a leave-one-out cross-validation procedure, only one fat sample from a pig fed with commercial feed, which simulated the fatty acid profile from free range animals, was incorrectly classified as having been fed on acorns and pasture. Using external validation, all of the samples were correctly classified. The most decisive fatty acids for distinguishing between groups, when using discriminant analysis were C16:1, C18:1, C17:0 and C18:0 for the first discriminant function, and C18:3, C14:0, C15:0, C22:0, C16:1 and C22:1 for the second discriminant function, ordered from the highest to the lowest coefficient. Some of the fatty acids important in distinguishing between groups are not the ones used by Spanish legislation to classify pigs in the different feeding categories. The results in this paper demonstrate the potential of statistical data treatment in the classification of animal feeding regimes.