## 3 Results
### Phytochemical Composition and Nutritional Properties
sativa_ cultivars, the results were very heterogeneous: \"Doree de Lyon\" (6.87 \(\pm\) 0.09 mg 100 g\({}^{-1}\) DW), \"Savoye\", and \"Toumive\" presented good amounts; no vitamin C was detected in \"Biancole\"; and the \"Contessa\", \"Neirana\", and \"Ruiana\" cv. \"Marrone-type\" cultivars showed higher mean values than European chestnuts, with a maximum in \"Marrone di Chiusa Pesio\" (7.62 \(\pm\) 0.41 mg 100 g\({}^{-1}\) DW). The vitamin C values were similar to the walnut and almond ones [47, 48]. Table S3 in the Supplementary Materials reports the nutritional properties of the chestnut extracts. The composition of the organic acids (Figure 7) was highly variable and specific to each cultivar. In general, the least abundant compounds were oxal and tartaric acids. The mean amounts in Japanese cultivars and sweet European chestnuts were similar (727.33 and 758.16 mg 100 g\({}^{-1}\) DW, respectively) and lower than Euro-Japanese hybrids (1012.98 mg 100 g\({}^{-1}\) DW) and \"marrone-type\" (939.29 mg 100 g\({}^{-1}\) DW). The Euro-Japanese hybrid \"Preccoc Migoule\" cv showed the highest content (1879.03 \(\pm\) 4.06 mg 100 g\({}^{-1}\) DW), as reported by [PERSON] et al. [4], and other important amounts were detected in \"Marsol\", \"Vignols\", and \"Marissard\" cv. Moreover, the group of European chestnuts showed a very wide range between the maximum value (1449.85 \(\pm\) 0.66 mg 100 g\({}^{-1}\) DW in \"Laguepie\") and the minimum one (172.38 \(\pm\) 55.48 mg 100 g\({}^{-1}\) DW in \"Gentile\"). Other varieties rich in organic acids were \"Rouffinette\", \"Primitiva di Roccamonfina\", and \"Toumive\", whereas \"Juda\" and \"Tempuriva\" were similarly detected in trace amounts. [PERSON] et al. [49] reported 146 \(\pm\) 11.1 mg 100 g\({}^{-1}\) DW for citric acid and 384 \(\pm\) 4.02 mg 100 g\({}^{-1}\) DW for malic acid in the \"Juda\" cultivar, a higher value than the levels detected in this study, as well as for in \"Lungal\" cv. In this case, the method of extraction may be an important factor influencing the organic acid content. The \"marrone-type\" chestnuts also showed a good number of organic acids, especially in \"Marrone della Valle di Susa\" (1809.85 \(\pm\) 70.63 mg 100 g\({}^{-1}\) DW), \"Marrone della Val Pellice\", and \"Marron Sauvage\". Organic acids are antioxidant molecules, sometimes used in pharmacological trials, as shown by some studies [50]; these compounds, together with fiber, can synergistically exert a biological action to maintain the digestive system in good health conditions. They increase the bioavailability of mineral elements (e.g., iron and calcium) in the diet. In particular, high levels of quinic acid may be metabolized to hippuric acid, which is useful to alleviate infections in the urinary tracts [51], whereas citric acid plays an important role in regulating the functioning of the urinary tract by inhibiting the adhesion of calcium oxalate crystals to renal epithelial cells [52]. Although the content of organic acids and their profile may well discriminate between different cultivars based on genotype, this variability may be also due to other factors: indeed, the levels of organic acids, as other volatile compounds, are influenced by conservation methods, drying, and extraction protocols [53]. This study confirmed that sucrose was the main component of the sugar class (Figure 8), in accordance with previous studies [3, 25, 54]. However, sucrose was not quantified in \"Tsukuba\", \"Colossal\", \"Bouche Rouge\", and \"Marrone di Castel del Rio\", probably due to hydrolysis during the storage. [PERSON] et al. [54] identified 14.96 \(\pm\) 0.46 g 100 g\({}^{-1}\) DW for sucrose, 2.22 \(\pm\) 0.21 g 100 g\({}^{-1}\) DW for fructose, and traces of glucose. Glucose and fructose were always detected in the analyzed extracts. A predominance of fructose over glucose was only observed in a few European cultivars, such as \"Bouche Rouge\", \"Marrone di Chiusa Pesio\", \"Garrone Rosso\", and \"Gabiana\".