Low dose γ-irradiation as a suitable solution for chestnut (Castanea sativa Miller) conservation: effects on sugars,...

Along with dehydration, the development of insects and microorganisms is the major drawback in chestnut conservation. Irradiation has been regaining interest as an alternative technology to increase food product shelf life. In the present work, the effects of low dose gamma irradiation on the sugar, fatty acid, and tocopherol composition of chestnuts stored at 4 °C for different storage periods (0, 30, and 60 days) was evaluated. The irradiations were performed in a 60Co experimental equipment, for 1 h (0.27±0.04 kGy) and 2 h (0.54±0.04 kGy). Changes in sugars and tocopherols were determined by high performance liquid chromatography coupled to refraction index and fluorescence detections, respectively, while changes in fatty acids were analyzed by gas-chromatography coupled to flame ionization detection. Regarding sugar composition, storage time proved to have a higher effect than irradiation treatment. Fructose and glucose increased after storage, with the corresponding decrease of sucrose. Otherwise, the tocopherol content was lower in nonirradiated samples, without a significant influence of storage. Saturated, monounsaturated, and polyunsaturated fatty acids levels were not affected, either by storage or irradiation. Nevertheless, some individual fatty acid concentrations were influenced by one of two factors, such as the increase of palmitic acid in irradiated samples or the decrease of oleic acid after 60 days of storage. Overall, the assayed irradiation doses seem to be a promising alternative treatment to increase chestnut shelf life, without affecting the profile and composition in important nutrients.