Free amino acid profile in Malus domestica cv Annurca apples from the Campania region and other Italian vegetables

The apple Malus domestica Borkh cv Annurca is a variety from the Campania Region (Southern Italy) known for its high quality and recognized with the ”Protected Geographical Indication” (PGI) trademark. Differences in cultivation area could help to guarantee the geographic origin of this product. Free amino acids of Annurca apples cultivated in the Campania Region were determined on an amino acid analyzer with post-column ninhydrin derivatization procedure and utilized in a chemometric approach. The main free amino acids present in samples from Annurca apples were asparagine (>70 mg/100 g), aspartic acid, glutamic acid and ophosphoserine (about 1-5 mg/100 g each). Other amino acids were detected in minor amounts (less than 1 mg/100 g). Subsequently, the cluster analysis indicated that the Annurca apples from Presenzano, Pietravairano, Vitulazio and Valle di Maddaloni (little villages of the Campania Region) may be distinguished on the basis of their free amino acid profiles. The confidence of the cluster obtained for apples, was tested considering the free amino acid profiles of other Italian vegetables. It is concluded that free amino acid profiles are good indicators of the geographic origin of Annurca apples and other vegetables, proposing a simple method compared with more tedious ones, which could be transferred to other laboratories, making easier the acquisition of raw data (free amino acid profiles)