Effect of hot air convective drying on the fatty acid and vitamin E composition of chestnut (Castanea sativa Mill.) slices

The aim of the present work was to study the effect of hot-air drying on the quality of chestnut slices, regarding fatty acid and vitamin E composition. Chestnut slices of two varieties, Longal and Judia, were dried in a tray dryer at 50 °C, for 1, 2, 4, 6, 8 and 10 h. Concerning fatty acids, at beginning both varieties presented significant different contents in C16:0, C18:0, C18:1, C18:2cc, C20:0 and C20:1, being C18:2cc the most abundant. Concerning vitamin E, both varieties had similar γ- and δ-tocopherol contents; however, after 10 h of drying their concentrations decreased in Longal (19.2 and 14.4 %, respectively). It was also in slices of Longal variety that a significant decrease was observed in C18:0 (15.0 %), C18:1 (19.4 %), C20:0 (14.3 %) and C20:1 (11.1 %) after 10 h of drying, suggesting this variety to be a little more heat sensible than Judia. Even though some variation on lipid composition was observed along drying of chestnuts, the variety showed to have a higher effect than the drying process itself. Thus, hot air convective drying seems to be an interesting process to apply in the future to this nut in order to produce a healthy snack, not causing potential losses from a nutritional point of view.Teresa Delgado acknowledges the Fundação para a Ciência e Tecnologia (FCT) for the financial support through the PhD Grant—SFRH/BD/82285/2011, CIMO through the PEst- OE/AGR/UI0690/2014 Project and REQUIMTE through the UID/ QUI/50006/2013 and NORTE-07-0124-FEDER-000069 projects, as well as POCTEP—Programa de Cooperação Transfronteiriça Espanha-Portugal through the RED/AGROTEC—Experimentation network and transfer for development of agricultural and agro industrial sectors between Spain and Portugal Project