Proximate Composition, Amino Acid Content and Antioxidant Activity of Different Potato Varieties from the Matese Plateau (Southern Italy)

Here, the proximate composition, total amino acid content and antioxidant activity of Agria, Désirée and Kennebec potato varieties cultivated on the Matese plateau (Campania region, Southern Italy) were evaluated. Significant differences were observed among varieties in terms of proteins (1.98–3.07 g/100 g FW), carbohydrates (12.05–15.78 g/100 g FW) and moisture (78.42–84.68 g/100 g FW), while lipids were consistently low (~0.1 g/100 g FW), ~2.6-fold lower than ‘gold’ potatoes, used as a reference. Ashes were relatively high (1.10–1.39 g/100 g FW), ~1.4-fold higher than ‘gold’ potatoes. Total amino acid profiles were similar, although statistically significant differences were observed for Glx (glutamic acid + glutamine) and Asx (aspartic acid + asparagine), which are the most abundant amino acids, followed by valine, arginine and lysine. The chemical score of essential amino acids highlights that Matese potato varieties have a high nutritional content of phenylalanine + tyrosine and threonine, with average chemical scores of ~99.8% and 91.6%, respectively, while leucine is the limiting amino acid. The free amino acid profile does not show statistically significant differences. The total phenolic content (TPC) of analysed varieties (57.85–123.27 mg GAE/100 g of FW) was higher than those reported in the literature and directly correlated with the evaluated antioxidant activity (ABTS and DPPH). Finally, Matese potatoes are rich in potassium, phosphorus, calcium and magnesium, with minor minerals (~1.6%) and selenium traces (~0.53 µg/100 g FW). Overall, these findings highlight the potential of Matese potatoes to enhance local consumption, preserve culinary heritage and support gastronomic tourism growth.