Validation of Gamma and Electron Beam Irradiation as Alternative Conservation Technology for European Chestnuts

Abstract

Chestnuts are widely consumed around the world, especially in China, which is the major producer. Portugal is the fifth biggest producer, reaching and income of 17 M€, with particular relevance for Trás-os-Montes region, which is responsible for 81% of Portuguese production. During postharvest storage, a number of pests tend to attack chestnuts, contributing to high economic losses. Since 2010, the most effective postharvest treatment, i.e. fumigation with methyl bromide, was banned in the European Union, urging producers to seek effective and reasonable alternatives. One alternative could be irradiation with gamma rays or electron beam, which is used in food commodities, legally regulated and allows outstanding results. Our research group has tested both irradiation types in chestnuts and studied the nutritional, antioxidant and other chemical parameters, obtaining promising results. Herein, we extended these studies to selected cultivars from Portugal and Italy in order to validate this technique as a viable alternative to fumigation. The selected irradiation dose (1 kGy) was chosen following previous results where it proved to be effective without causing remarkable changes in chemical or antioxidant profiles. To obtain a global knowledge about how each cultivar reacts to irradiation, principal component analysis was performed using all the measured parameters. Despite the detected differences among cultivars, which differentiated particularly Palummina and Cota, it was verified that irradiation did not cause changes in chemical and antioxidant parameters that could enable defining distinctive features among irradiated and non-irradiated chestnuts.Hence, the results herein reported might be seen as a new step toward the completion of irradiation as feasible conservation technology, independently of chestnuts origin.

Developing radio frequency technology for postharvest insect control in milled rice

“…Alternative physical methods have been proposed to replace chemical fumigations, including ionizing irradiation (Johnson et al, 1998;Follett, 2008;Carocho et al, 2014), controlled atmosphere (Zhou et al, 2000;Neven and Rehfield-Ray, 2006), cold storage (Aluja et al, 2010), low pressure (Jiao et al, 2013;Suhem et al, 2013), conventional heating (Hansen, 1992), microwave (Zhao et al, 2007;Vadivambal et al, 2007;Yadav et al, 2014;Jian et al, 2015), and radio frequency (RF) heating Alfaifi et al, 2014). However, each of these methods has disadvantages based on the treatment effectiveness and cost.…”

Ionizing radiation applications for food preservation: effects of gamma and e-beam irradiation on physical and chemical parameters of chestnut fruits

“…Neither irradiation dose nor storage time seemed to exert high influence over organic acids profile. Concluding that, in line with previous parameters, organic acids are not greatly affected by gamma or electron-beam irradiation (Carocho et al, 2013a;Carocho et al, 2013b).…”

“…Sugars are good conservation quality indicators (Kazantzis et al, 2003), (Iwata & Ogata, 1959;Guo-xin et al, 1980;Fernandes et al, 2011a;Fernandes et al, 2011b) or electron beam (Carocho et al, 2012b;Carocho et al, 2013b). In fact, the main differences in sugars profiles resulted from storage time effect, in line with the observed for other nutritional parameters.…”

“…Regarding chestnut fruits, fatty acids profiles differences were mostly due to the effect of storage time, while irradiation treatment caused only slight alterations, either when using gamma (Fernandes et al, 2011a;Fernandes et al, 2011b;Barreira et al, 2012;Carocho et al, 2013b), as well as electron beam (Carocho et al, 2012b;Carocho et al, 2013a) irradiation.…”

“…Food processing technologies, gamma or electron-beam, must allow the integral maintenance of food properties to fulfill quality requirements. The effect of irradiation on food quality parameters of European varieties was validated first for gamma radiation (Antonio et al, 2011a;Fernandes et al, 2011a;Fernandes et al, 2011b;Barreira et al, 2012;Antonio et al, 2012a), that were object of a review comparing the results with other authors for other varieties of chestnut fruits , and more recently for electron beam radiation Carocho et al, 2012b; Barreira et al, 2013;Carocho et al, 2013a;Carocho et al, 2013b).…”