Percorrer por autor "Alkan, Hasan"
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- Chemometric characterization of gamma irradiated chestnuts from TurkeyPublication . Barreira, João C.M.; Antonio, Amilcar L.; Günaydi, Tuğba; Alkan, Hasan; Bento, Albino; Botelho, M. Luísa; Ferreira, Isabel C.F.R.Chestnut (Castanea sativa Miller) is a valuable natural resource, with high exportation levels. Due to their water content, chestnuts are susceptible to storage problems like dehydration or development of insects and microorganisms. Irradiation has been revealing interesting features to be considered as an alternative conservation technology, increasing food products shelf-life. Any conservation methodology should have a wide application range. Hence, and after evaluating Portuguese cultivars, the assessment of irradiation effects in foreign cultivars might act as an important indicator of the versatility of this technology. In this work, the effects of gamma irradiation (0.0, 0.5 and 3.0 kGy) on proximate composition, sugars, fatty acids (FA) and tocopherols composition of Turkish chestnuts stored at 4 ºC for different periods (0, 15 and 30 days) were evaluated. Regarding proximate composition, the storage time (ST) had higher influence than irradiation dose (ID), especially on fat, ash, carbohydrates and energetic value. Sucrose exhibited similar behavior in response to the assayed ST and ID. The prevalence of ST influence was also verified for FA, tocopherols and sucrose. Lauric, palmitoleic and linolenic acids, were the only FA that undergone some differences with ID. Saturated, monounsaturated and polyunsaturated fatty acids levels were not affected neither by storage nor irradiation. α-Tocopherol was the only vitamer with significant differences among the assayed ST and ID. Overall, Turkish cultivars showed a compositional profile closely related with Portuguese cultivars, and seemed to confirm that gamma irradiation in the applied doses did not change chestnut chemical and nutritional composition.
- Effect of gamma irradiation and extended storage on selected chemical constituents and antioxidant activities of sliced mushroomPublication . Fernandes, Ângela; Barreira, João C.M.; Günaydi, Tuğba; Alkan, Hasan; Antonio, Amilcar L.; Oliveira, Beatriz; Martins, Anabela; Ferreira, Isabel C.F.R.Due to its exquisite odor and taste, Boletus edulis Bull.: Fr. mushroom is being increasingly used throughout the world. However, the availability of this product is highly restrained by its seasonality and perishability, demanding special care to keep its quality. Furthermore, mushrooms are often distributed in sliced form, and the slicing operation requires special treatments, besides augmenting the possibility of microbial contamination. Some techniques are currently applied to sliced mushrooms, but these processes had adverse effects on nutrients, odor, texture and taste, besides requiring expensive equipment. Food irradiation is being studied as an alternative technology to improve the quality and durability of determined products, having been previously applied in several mushroom species. Herein, gamma irradiation was applied to dried and sliced samples of B. edulis, at high doses (2, 6 and 10 kGy), and the effects on nutritional, chemical and antioxidant parameters were evaluated throughout storage (6 and 12 months). The results obtained for the chemical parameters do not advised storing B. edulis for such extended periods, since some relevant changes were detected, especially in samples stored for 12 months. In general, the gamma irradiation treatment did not cause further changes in the chemical composition, besides having a slightly positive effect in keeping the antioxidant activity and most of the bioactive compounds profiled in this work, contributing to maintain the potential health effects of this exquisite food, even after extended storage periods.
- Gamma irradiation improves the nutritional profile of dried and sliced wild Boletus edulis Bull.Publication . Fernandes, Ângela; Barreira, João C.M.; Antonio, Amilcar L.; Günaydi, Tuğba; Alkan, Hasan; Oliveira, Beatriz; Martins, Anabela; Ferreira, Isabel C.F.R.Boletus edulis Bull. is a seasonal mushroom with high perishability (shelf-life: 1-3 days at room temperature) [1]. Drying is a widely used postharvest technology, which overcomes those problems. Nevertheless, after slicing, mushrooms need special care to keep their quality [2]. A possible treatment is applying ionizing radiation. Herein, the effects of gamma irradiation (2, 6 and 10 kGy) on nutritional parameters were analyzed in wild B. edulis dried and sliced samples (Bragança, Northeast of Portugal, 2013). Irradiation was performed at Gamma-Pak Sterilizasyon (Çerkezköy, Turkey). The nutritional parameters were determined throughout the storage time (0, 6 and 12 months) according to official procedures. The results were compared considering the mean value of each storage time (ST), including all gamma irradiation (GI) doses, and also the mean value of each dose, with all ST included, allowing verifying the effect of each factor independently. Despite the detected significance in the interaction among ST and GI for all assayed factors, some defined conclusions were obtained: fat, protein and ash contents gave maximal contents in samples irradiated with 10 kGy, while the lowest values were detected in non-irradiated samples. Regarding the effect of ST, these same parameters presented minimal values in samples stored during 12 months. The variation in carbohydrates, which was calculated by difference, was precisely the opposite of the previously described. The variation in energy was less pronounced for both effects. Overall, irradiation treatment, particularly the 10 kGy dose, tended to improve the nutritional profile of sliced-dried B. edulis samples. References [1] Jaworska, G., Bernaś, E. (2009). Food Chemistry, 113, 936-943. [2] Oliveira, F., Sousa-Gallagher, M. J., Mahajan, P. V., & Teixeira, J. A. (2012). Journal of Food Engineering, 108, 507–514.
- Influência da dose de radiação gama na cor de castanhas de origem Portuguesa e Turca (Castanea sativa Mill.)Publication . Antonio, Amilcar L.; Ramalhosa, Elsa; Fernandes, Ângela; Barreira, João C.M.; Botelho, M. Luísa; Günaydi, Tuğba; Alkan, Hasan; Quintana, Begoña; Bento, AlbinoA produção de castanha (Castanea sativa Mill) assume grande importância em Portugal, sendo uma parte significativa exportada. Devido ao facto da fumigação com brometo de metilo (técnica utilizada para eliminar pragas e muito usada em castanha para exportação) ter sido proibida, tornou-se necessário encontrar alternativas. No presente trabalho estudou-se o efeito da irradiação gama sobre a cor (externa e interna) de castanhas, de forma a avaliar a potencialidade desta técnica em tratamentos futuros de desinfestação deste fruto. Irradiaram-se castanhas de origem Portuguesa e Turca, sujeitando-as aos seguintes tratamentos: 0, 0,5 e 3,0 kGy. Avaliaram-se os parâmetros de cor de Hunter (L, a, b) aos 0, 15 e 30 dias. Algumas diferenças na cor exterior das castanhas Portuguesas e Turcas, em relação ao parâmetro a, foram detectadas. Contudo, para ambas as castanhas, não se observou que os parâmetros de cor variassem com a dose aplicada. Em relação ao interior, alguns parâmetros variaram ao longo do armazenamento. No entanto, em relação à dose aplicada, não se detectou o amarelecimento do fruto, indicando que esta tecnologia não afecta a cor numa extensão superior à resultante do próprio armazenamento, desde que aplicada na gama de doses estudada.