Browsing by Author "Ramalhosa, Elsa"
Now showing 1 - 9 of 9
Results Per Page
Sort Options
- Chemical and Physical Properties of Some Hazelnut Varieties Grown in PortugalPublication . Ferrão, Ana Cristina; Guiné, Raquel P. F.; Ramalhosa, Elsa; Lopes, Arminda; Rodrigues, Cláudia Filipa; 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 (λ = 0.007) and water activity (λ = 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.
- Efeito da embalagem na conservação da avelãPublication . Correia, Paula; Filipe, Ana Margarida; Ramalhosa, Elsa; Guiné, RaquelAs condições de armazenagem da avelã são muito importantes para manter as suas qualidades nutricionais e organoléticas. Pretendeu-se avaliar o efeito da embalagem a vácuo e em sacos de ráfia nas características físico-químicas de avelãs, tanto nos frutos com casca como sem casca (miolo). Estas amostras foram armazenadas nas mesmas condições numa garagem, durante um ano, realizando-se a medição da humidade relativa e temperatura. Foram avaliadas as seguintes propriedades: humidade, atividade da água (aw), cor e estabilidade oxidativa da gordura, tanto na amostra inicial, como após 6 meses e 12 meses de armazenagem. Dos resultados observou-se que a temperatura e a humidade relativa média durante o período de armazenagem foram de 16,8ºC e 65,2% respetivamente. Verificou-se uma diminuição no valor da atividade da água e do teor de humidade nos primeiros meses de armazenagem, sendo de 0,76 e 8,1% respetivamente. A aw nos 6 meses variou entre 0,61 e 0,65, aumentado até aos 12 meses, sendo este aumento mais acentuado para as amostras com casca armazenadas a vácuo e para as amostras sem casca embaladas em ráfia. A humidade também diminuiu durante o período de conservação, os frutos inicialmente apresentavam um valor de 8,1% e o valor mínimo foi obtido para o miolo dos frutos se casca (4,7%). A humidade ao longo do armazenamento não apresentou grandes variações dos 6 para os 12 meses para todas as amostras. No que respeita à cor, de um modo geral, não houve variações significativas nas coordenadas L*, a* e b ao longo do armazenamento. A estabilidade da gordura diminuiu ao longo do tempo de armazenagem, registando-se uma diminuição mais acentuada dos 6 para os 12 meses, sendo as avelãs com casca embaladas a vácuo aquelas que apresentaram maior estabilidade oxidativa. Deste estudo pode concluir-se que as a embalagem e a duração do período de armazenagem influenciam as várias amostras, com maior incidência na atividade da água e na estabilidade oxidativa da gordura das avelãs.
- Effect of different storage conditions on the stability and safety of almondsPublication . Rodrigues, Paula; Jelassi, Arij; Kanoun, Elifa; Sulyok, Michael; Correia, Paula; Ramalhosa, Elsa; Pereira, Ermelinda Lopes
- Evaluation of some physical and chemical properties of hazelnutsPublication . Guiné, Raquel; Rodrigues, Cláudia; Correia, Paula; Ramalhosa, ElsaIn this work were evaluated some physical and chemical properties of hazelnuts from two varieties (Buttler and Longa), namely colour, texture and density at the physical level and moisture, total fat, fat oxidation, ash, protein and crude fibre as concerns the chemical composition, following established procedures. The results obtained showed that the colour of the hazelnuts varied according to the point of measurement and also depending on the variety, being the Longa clearer in all points except for the core, in which the colour was equal to Butler. Regarding texture, the Butler was harder in the shell but softer in the core as compared to Longa, which in turn showed higher friability. Regarding density, no visible differences were found between varieties, but the bulk density was naturally lower than the true density in all cases, i.e., for measurements made with and without the shell, respectively. The moisture content was higher for Butler variety, 7.13%, and this also had the highest water activity. The fat content was high, as expected, around 60% in both cases, and the time for fat oxidation was lower for the Butler variety, thus indicating a lower stability to oxidative degradation. The ash content was higher for Longa variety, which was also richer in terms of protein, 15.60 %. The fibre content, however, was higher for Butler variety, 11.11%.
- Extraction solvents’ influence on the content of bioactive compounds and antioxidant activity of pansiesPublication . Ramalhosa, Elsa; Fernandes, Luana; Pereira, José; Saraiva, Jorge; Casal, SusanaIntroduction: Pansies (Viola×wittrockiana) are a rich source of natural antioxidants with beneficial effects on human health. Objetives: The aim of our study was to investigate solvents’ influence (water, methanol, water:acetone (6:4, v/v)) on the extraction of bioactive compounds and antioxidant activity of pansies extracts. Methods: The bioactive compounds analyzed were the following: flavonoids, hydrolysable tannins and monomeric anthocyanins, as well as total phenols by the total reducing capacity assay (TRC). The antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power assays. A Principal Component Analysis (PCA) was performed to differentiate pansies extracts. Results: The solvents that yielded extracts with the highest contents of hydrolysable tannins and TRC were methanol and water:acetone (6:4, v/v). To extract the highest contents of monomeric anthocyanins, methanol should be used (5.93 mg Cy 3-glu/g flower, d.w), while for flavonoids, water:acetone (6:4, v/v) was the preferred yielding an extract with 115 mg QE/g flower d.w. Water turned out to be the least effective solvent, giving extracts with the lowest antioxidant activity. In addition, methanol or water:acetone extracts were clearly distinguished from aqueous ones through a PCA analysis. Conclusions: Our results show that the bioactive compounds and antioxidant activity of pansies’ extracts are affected by the solvent used.
- Hazelnut Storage at Controlled Conditions with Different Packaging MaterialsPublication . Correia, Paula; Filipe, Ana; Ramalhosa, Elsa; Guiné, RaquelThe nutritional and organoleptic quality of hazelnuts can be greatly influenced by storage conditions. The aim of this study was to evaluate the effect of vacuum packaging and raffia bags on the physicochemical characteristics of hazelnuts, both in shelled and unshelled (kernel) fruits when stored under controlled conditions of temperature (25ºC) and relative humidity (65%), simulating the average annual conditions of a tropical country. The following properties were evaluated: moisture, water activity (aw), color and fat oxidative stability, both in the initial sample and also after 6 and 12 months of storage. After 6 months, the gradual degradation of the shelled and without shell (kernel) hazelnuts stored in the raffia bags was clear and they were completely damaged at the end of 12 months of storage. There was a decrease in the initial values of water activity and moisture content (being 0.76 and 8.1% respectively) in the first 6 months of storage. The aw varied significantly after 6 months, between 0.60 and 0.71 in the samples packed in raffia. The moisture of vacuum packed fruits decreased from 6 to 12 months, reaching values between 4.3% and 4.8%. As far as color is concerned, there were generally no significant variations in the L *, a * and b* coordinates during storage in the hazelnut shell or kernel. Fat stability decreased over the shelf life, with a marked decrease in the first 6 months for hazelnuts in raffia bags and after 6 months for vacuum packed ones, with vacuum packed hazelnuts showing higher oxidative stability. From this study it can be concluded that vacuum packaging allows the best preservation of hazelnuts, with color being the least affected property. Both packaging and length of storage influence the quality of the hazelnuts.
- New Foods, New Consumers: Innovation in Food Product DevelopmentPublication . Guiné, Raquel; Ramalhosa, Elsa; Cruz-Lopes, LuísaBACKGROUND: Today, new lifestyles, higher incomes and consumer awareness are creating consumer demand for a year-round supply of high-quality, diverse and innovative food products. However, when it comes to innovation, the food sector is less changeable when compared to other sectors, such as high technology. Still, in the past decades much and important developments have been achieved in several areas related to foods and the food industry. METHODS: A systematic review of scientific literature was conducted on Science Direct. The topics investigated were: aspects related to innovation in food development (such as the transfer of innovation, open innovation, collaborative innovation and consumer perception and its role in the developing process); the innovation in the food industry (particularly regarding the processing technologies and packaging, which are two prominent areas of innovation in this sector nowadays); the innovation in the cooking sector (particularly in regards to the molecular gastronomy and science based cooking). RESULTS: A total of 146 articles were included in the review and the aspects focused allowed confirming that innovation has been recognized as a key driver of economic growth. Within the framework of ‘open innovation’, a number of key issues related to the acquisition of external knowledge in food technology must be taken into consideration. Food product development is highly dependent on the consumer perception and acceptance, and hence it is of utmost importance to include the consumer in the development process to minimize failure probabilities. The sectors of the food industry where important developments and innovation are registered include the processing technologies and the packaging systems, where the latest progresses have produced very significant outcomes. CONCLUSION: The present work allowed verifying the latest improvements and trend towards food product development from two perspectives, the product itself and the industrial processing. This sector is undoubtedly a major key for the success and competitiveness nowadays in the food industry.
- Physico-chemical and sensory characterization of fruit jams of S. Tomé and PríncipePublication . Ramalhosa, Elsa; Sousa, Agostinho; Fernandes, Luana; Delgado, Teresa; Fidalgo, Maria; Pereira, JoséIntroduction: São Tomé and Príncipe has a wide variety of fruit trees, being most of the fruits consumed in fresh. In certain periods of the year, fruits are available at significant amounts; however, it is not common to use the surplus of those fruits. Thus, this excess may be used in the preparation of other fruit based products (ex. jams), in order to increase product diversity and allow the annual consumption of these seasonal fruits. Objetives: Valorise fruits’ production in S. Tomé and Príncipe. Methods: Preparation of jams of banana, ambarella, guava (dark and light) and papaya, with two levels of sugar, and perform their physico-chemical characterization (color, pH, moisture and acidity). Furthermore, sensory analysis was also done, through preference and acceptability tests. Results: The jams prepared had different colours, acidity values, and moisture and ash contents, demonstrating the possibility of producing different products by changing the formulation. Regarding jams preference, 60% of the consumers preferred the less sweet in the case of banana and guava (light), whereas, over 67% of the panellists preferred the sweetest ambarella jam. Concerning dark guava and papaya, the percentages were similar for both sugar contents. For all attributes analysed (appearance, colour, taste, acidity, sweetness and global evaluation), most of the panellists liked slightly all jams.Conclusion: Jams production in S. Tomé and Príncipe may be a promising activity.
- Physicochemical Analysis of Seven Hazelnut Varieties Cultivated in PortugalPublication . Ferrão, Ana Cristina; Guiné, Raquel P. F.; Ramalhosa, Elsa; Martins, Hugo; Gonçalves, Roberto; Correia, Paula