Expansin-like A (EXLA) proteins belong to one of the four main families within the expansin superfamily, a group of plant proteins essential for cell wall loosening. Here, we report, for the first time, the purification of a novel EXLA, named cpEXLA, from canihua seeds. cpEXLA (yield ~0.16 mg per 100 g of seeds) is a 29 kDa glycoprotein with a high melting temperature (Tm of 86.75 ± 1.06 °C). Elucidation of its primary structure reveals that the mature protein consists of 246 amino acids, ten of which are cysteine residues forming five disulphide bridges. Structural studies based on 3D model prediction reveal the presence of N- and C-terminal domains, which are typical of EXLAs and rich in β-sheets, as confirmed by circular dichroism (CD) spectroscopy. Furthermore, comparative analysis of amino acid sequences between cpEXLA and 219 similar EXLAs, retrieved from dicotyledonous genomes and transcriptomes, identified eighteen invariant amino acid residues: eleven in the N-terminal domain and seven in the C-terminal domain. Finally, phylogenetic analysis of EXLAs in dicotyledonous species shows a close relationship with other EXLAs from the Amaranthaceae family, confirming that EXLA proteins are highly conserved among dicotyledonous plants. Overall, cpEXLA represents an intriguing native tool for studying cell wall evolution and the functional role of EXLAs.

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.