Browsing by Author "Lopes, Arminda"
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- Chemical and physical properties of some hazelnut varieties grown in PortugalPublication . Ferrão, Ana Cristina; Guiné, Raquel P.F.; Ramalhosa, Elsa; Lopes, Arminda; Rodrigues, Cláudia; Martins, Hugo; Gonçalves, Roberto; Correia, PaulaHazelnuts are one of the most appreciated nuts worldwide due to their unique organoleptic and nutritional characteristics. The present work intended to analyse several physical and chemical properties of different hazelnut varieties grown in Portugal, namely Tonda de Giffoni, Grada de Viseu, Segorbe, Longa de Espanha, Butler, Gunslebert, and Negreta. In general, the results revealed statistically significant differences between the varieties under study. The Gunslebert had more elongated hazelnuts and with heavier shelled fruits, while the kernels of the Grada de Viseu revealed to be heavier. Grada de Viseu was harder in the shell, Gunslebert had a harder core, and Segorbe was more resistant to fracture. Fat was the more representative component for all varieties and in some cases the values of moisture and water activity were over the recommended amount ( 0.62). Tonda de Giffoni was the variety with the highest induction time, indicating the highest oxidation stability. Moreover, discriminant analysis revealed that the variables more important to distinguish the varieties were protein ( = 0.007) and water activity ( = 0.010). The results of this study help to better understand the differences between some hazelnut varieties that are cultivated in Portugal, which gives important hints for all players in the hazelnut sector.
- Influence of different parameters on the characteristics of hazelnut (var. Grada de Viseu) grown in PortugalPublication . Ferrão, Ana Cristina; Guiné, Raquel P.F.; Ramalhosa, Elsa; Lopes, Arminda; Rodrigues, Cláudia; Martins, Hugo; Correia, Paula“Grada de Viseu” is an indigenous hazelnut variety from Portugal, and it is considered by the producers as the most important variety in terms of production and productivity. Therefore, the aim of this study was to assess the influence of harvest year (2017/2018/2019) and location of production (Viseu/Faia) on some physical and chemical properties of the variety “Grada de Viseu,” namely biometric parameters, colour, true and bulk densities, texture parameters (hardness and friability), and chemical composition. The results showed that the fruits of the samples harvested in 2019 had higher values of height, width, and thickness. Hazelnuts from 2018 had a clearer shell, independently of the location of production, but only the samples from Faia harvested in 2018 had a clearer kernel. As for the texture, the fruits grown in Viseu harvested in 2018 had a harder shell and was more resistant to fracture, whereas the sample from 2019 had a harder kernel. In all cases, fat was the major chemical component. The sample from 2019 had a water activity greater than 0.62, meaning that its stability was not guaranteed. “Grada de Viseu” from Faia in 2018 presented a higher induction period and, therefore, was the one with the highest oxidation stability. The year of production showed to be the best predictor for almost every chemical and biometric characteristics. In general, it was possible to verify that harvesting year and geographical location influence hazelnut characteristics.
- Physical and chemical properties of some hazelnut varieties grown in PortugalPublication . Ferrão, Ana Cristina; Guiné, Raquel P.F.; Gonçalves, Roberto; Lopes, Arminda; Ramalhosa, Elsa; Correia, PaulaWorldwide there has been an increase in the demand for dried fruits. In Portugal, hazelnut is the dry fruit with the less cultivated area, however the country has conditions for a good production. This work intended to analyse the physical and chemical properties of seven hazelnut varieties grown in Portugal, named Negreta, Gunslebert, Tonda de Giffoni, Grada de Viseu, Butler, Segorbe and Longa de Espanha. For that purpose, hazelnut fruits were evaluated for biometric characteristics, apparent and true densities, colour, texture, nutritional parameters (moisture, ash, lipids content, protein, fibre and water activity), oxidative stability index and specific extinction coefficients (K232, K264, K268 and K272). The results showed that, in general, there were statistically significant differences among the varieties under study. Hazelnuts of variety Longa de Espanha revealed to be more elongated and the variety Butler had heavier fruits, both in shell and kernel. The variety Grada de Viseu was harder in the shell being the kernels of variety Segorbe softer but more resistant to fracture. For all varieties, fat was the major chemical component. The lowest extinction coefficient, K232, was found for Negreta, indicating that this variety presented a lower degree of primary oxidation products. The other specific extinction coefficients were relatively low for all samples. Moreover, Tonda de Giffoni was the variety with the higher oxidation stability. This work highlighted the differences in hazelnuts according to the variety, confirming the importance to perform more studies in this area since these results can be very useful in the hazelnut sector.