Application of Traditional Cooking Methods in Chestnut Processing: Effects of Roasting and Boiling on Secondary Metabolites and Antioxidant Capacity in Castanea spp. Fruits

More information on the effects of traditional cooking methods (roasting or boiling) on the chestnut composition may be important if health-promoting aspects are considered. The main aims of this study were to investigate and describe the phenolic profile and antioxidant capacity of raw, boiled, and roasted chestnuts from several Castanea spp. genotypes, evaluating the influence of the application of different traditional cooking methods on the nut phytochemical composition by chromatographic and spectroscopic strategies. The amounts of phenolics were used as selected variables together with total polyphenol content and antioxidant capacity to perform a Principal Component Analysis (PCA). Catechins and tannins were the main molecules in the phenolic phytocomplex, reaching 30–40% of the total, followed by phenolic acids (5–20%) and flavonols (about 5%). Gallic and ellagic acids were the most important phenolic acids in raw and processed chestnuts (about 20–70 mg·100 g−1 dried weight-DW and 10–50 mg·100 g−1 DW, respectively). Both of the cooking processes significantly influenced the polyphenolic content and the relative antioxidant capacity. This research may support and confirm the potential use of chestnuts for human health, increasing the information on the phenolic pattern of differently processed Castanea spp. fruits from different genotypes to (i) assess the potential health-positive effects, (ii) help processing companies to select specific varieties to commercialise in the market, and (iii) increase the use of these fruits with the relative increase in income for the producers.