Browsing by Author "Correia, Ana"
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- Antioxidant capacity, radical scavenger activity, lipid oxidation protectionPublication . Correia, Ana; Jordão, AntónioThe aim of this study was to investigate the antioxidant capacity, radical scavenger activity, lipid oxidation protection and antimicrobial activity of grape extracts from 12 different red grape varieties cultivated in Portugal. The mean values of total phenolic content quantified in grape extracts varied from 833.7 to 2005.6 mg/L gallic acid. Antioxidant capacity results showed different values for each grape variety ranging from 3.96 to 32.96 mm/L Fe(II). The scavenger activity values ranged from 15.99% to 54.82% for the superoxide radical and from 11.79% to 29.67% for the hydroxyl radical. The grape extracts with the highest antioxidant capacity had a positive effect on the lipid oxidation protection and induced low peroxide values in butter samples. Finally, concerning antimicrobial activity, grape extracts from Touriga Nacional and Tinta Roriz grape varieties had significant antimicrobial activity, especially notable for total mesophilic aerobics.
- Avaliação Comparativa de Queijos Portugueses de Cabra e OvelhaPublication . Guiné, Raquel; Correia, Paula; Correia, AnaSeis queijos portugueses produzidos unicamente com leite de ovelha ou de cabra, adquiridos numa grande superfície, foram avaliados ao nível físico (textura e cor), químico (humidade, aw, cinzas proteína e gordura) e sensorial (perfil de preferência). Ao nível químico, os resultados obtidos revelam alguma variabilidade entre amostras por tipo de queijo, sendo a amostra de queijo de ovelha V a que apresentou valores de proteína e gordura mais elevados, 29,7% e 63,5%, respetivamente. Também foi essa amostra que, ao nível dos parâmetros físicos avaliados, se destacou das restantes, sendo a mais corada, com maior dureza, mastigabilidade, gomosidade, maior firmeza da casca e da pasta. Contudo, ao nível sensorial foi a amostra com menor preferência dos provadores.
- Comparative evaluation of Portuguese goat and sheep cheesesPublication . Guiné, Raquel; Correia, Paula; Correia, AnaCheese is a solid food made by coagulating milk of different animals. It has a great expression worldwide and there is a great diversity in the types of cheese between and within different countries. Maturation (or cure) plays a key role in the development of the individual characteristics of each cheese. Sheep milk is very rich, containing higher amounts of total solids (19.3%), protein (4.5%) and fat (7.4%), of which most are glycerides (98%). Goat's milk is characterized by having 14.1% dry weight, 3.5% fat and 4.5% protein. In this work, six Portuguese cheeses made exclusively from sheep or goat milk were evaluated at the physical (texture and colour), chemical (moisture, aw, ashes protein and fat) and sensory (preference profile) levels. At the chemical level the results show some variability between samples by type of cheese, and the sample of sheep's cheese V presented higher values of protein and fat, 29.7% and 63.5%, respectively. This sample was also at the level of the physical parameters evaluated the one that stood out from the others, being darker (lower L*) and with a greater predominance of red (higher positive a*) and yellow (higher positive b*). With respect to texture, specifically the parameters of hardness, gumminess and chewiness, the sample of sheep cheese V resented the highest values. The samples of goat cheese were very similar among themselves in terms of chemical properties and also texture. At the sensory level, the sensory profiles of samples from sheep’s cheese V and goat’s cheese C are very distinct from the rest. While sheep’s cheese V has high intensity for the attributes of skin colour, colour of the paste, odour intensity, flavour intensity, acid taste and texture, the goat’s cheese C has lower values except for the salty attribute. However, considering the preference of the panellists, sheep’s cheese V was the least preferred of all samples, being the most appreciated the cheese samples goat B and sheep S.
- Conhecimento da População Portuguesa sobre Fibras AlimentaresPublication . Guiné, Raquel; Martinho, Célia; Correia, Ana; Gonçalves, Fernando; Abrantes, José Luís; Carvalho, RenatoAs fibras têm sido objecto de estudo nas últimas décadas e um dos temas frequentemente abordado é a relação entre fibra alimentar e os benefícios para a saúde. Este trabalho pretendeu fazer uma análise estatística do conhecimento da população portuguesa relativa às fibras alimentares. Foi realizado um inquérito por questionário entre Abril e Junho de 2011 a uma amostra de 182 indivíduos. Foram abordados temas como hábitos de consumo, conhecimento sobre fibras, meios de divulgação e informação, rotulagem dos alimentos, relação entre fibras e saúde, entre outros. Alguns dos resultados obtidos indicam que aproximadamente 70% dos inquiridos possui idade entre 18 e 40 anos, ensino universitário e vive no meio urbano. Os resultados mais relevantes indicam que por dia apenas 13% dos inquiridos comem duas refeições com legumes e/ou saladas e 9% come no mínimo 3 peças de fruta. Os cereais integrais nunca são consumidos por 41% e apenas 18% o fazem pelo menos uma vez por semana. Cerca de 35% dos inquiridos sabem qual a origem das fibras e aproximadamente 70% afirma que existe maior quantidade de fibras nas leguminosas, fruta com casca e nos alimentos integrais. A consulta dos rótulos dos alimentos revela interesse por parte de 80% dos inquiridos, sendo que, do total de respostas, apenas 10% consulta sempre o rótulo. O teor de fibras que o alimento possui não é do interesse de 43% dos inquiridos tendo em conta que esta informação nunca é consultada ou então isso é feito raramente. Um valor semelhante (39%) refere que a quantidade de fibras não é tida em conta aquando da escolha dos alimentos. A grande maioria (90%) dos inquiridos tem a noção de que a ingestão de fibras contribui para a prevenção e tratamento de doenças. Das várias doenças referidas no inquérito, as mais citadas foram a prisão de ventre (86%), obesidade (80%), doenças cardiovasculares e colesterol (7 %) e o cancro do intestino (69%). Relativamente aos meios de divulgação e informação sobre fibras alimentares, a escola (44%) e a televisão (41%) foram considerados os meios de divulgação mais adequados para incentivar o consumo, mas, na realidade, são os centros de saúde e hospitais (25%) que têm mais informação disponível. Com a realização deste trabalho foi possível concluir que o conhecimento dos inquiridos acerca de fibras alimentares é insuficiente, e que apesar de lhes ser atribuída grande importância no tratamento e prevenção de doenças, o nível de ingestão é muito baixo.
- Effect of Thistle Ecotype in the Physical-Chemical and Sensorial Properties of Serra da Estrela CheesePublication . Guiné, Raquel; Tenreiro, Marlene; Correia, Paula; Barracosa, Paulo; Correia, AnaThe objective of this study was to evaluate the physical and chemical characteristics of Serra da Estrela cheese and compare these results with those of the sensory analysis. For the study were taken six samples of Serra da Estrela cheese produced with 6 different ecotypes of thistlein a dairy situated in Penalva do Castelo. The chemical properties evaluated were moisture content, protein, fat, ash, chloride and pH; the physical properties studied were color and texture; and finally a sensory evaluation was undertaken. The results showed moisture varying in the range 40- 48%, protein in the range 15-20%, fat between 41-45%, ash between 3.9-5.0% and chlorides varying from 1.2 to 3.0%. The pH varied from 4.8 to 5.4. The textural properties revealed that the crust hardness is relatively low (maximum 7.3 N), although greater than flesh firmness (maximum 1.7 N), and also that these cheeses are in fact soft paste type, with measurable stickiness and intense adhesiveness. The color analysis showed that the crust is relatively light (L* over 50), and with a predominant yellow coloration (b* around 20 or over) although with a slight greenish tone (a* negative). The results of the sensory analysis did not show great variability for most of the attributes measured, although some differences were found in attributes such as crust thickness, crust uniformity, and creamy flesh.
- Evaluation of the physical, chemical and sensory propertiesPublication . Guiné, Raquel; Almeida, Inês; Correia, Ana; Gonçalves, FernandoThe main objective of the present work was to dry grapes of Crimson variety through different method- ologies in order to find an alternative for the production of raisins. Different methodologies were used for drying: so- lar direct exposition in a greenhouse and in convective drying chambers with constant air flow at two tem- peratures: 50 and 60 C. Some chemical analyses were made, namely for total sugars, acidity, total phenols, total anthocyanins and total tannins. Also some physical prop- erties were evaluated, specifically color and texture. A sensorial analysis of the dried products was undertaken to evaluate the acceptability by consumers. The raisins pro- duced by the different methodologies didn’t show sig- nificant differences at the chemical and physical levels. However, it was observed that the dried samples contained higher amounts of total phenolic compounds, anthocyanins and tannins in comparison to the fresh grapes. Sensory evaluation result showed that dried grapes produced using different methodologies was similar to commercial raisins.
- Study About the Knowledge and Attitudes of the Portuguese PopulationPublication . Martinho, Célia; Correia, Ana; Gonçalves, FMJ; Abrantes, José Luís; Carvalho, R; Guiné, RaquelThe association between dietary fiber, health benefits and healthy food has been studied in recent years. The food industry, to accompany the strong interest shown by consumers, has placed at their disposal new products, rich in dietary fiber. This work intended to make a statistical analysis of the knowledge of the Portuguese population about fibres, and for that a survey was conducted of a sample of 182 individuals. Some topics covered included consumption habits, knowledge about fibres, means of dissemination and information, food labelling or the relationship between fibres and health, among others. The most relevant results indicate that only 13% of respondents eat two meals a day with vegetables and/or salads and 9% eat at least 3 pieces of fruit. Whole grains are never consumed by only 41% and 18% do so at least once a week. Around 35% of respondents know about the origin of fibres whereas 70% say there is a greater amount of fibre in legumes, fruit with skin and whole foods. The consultation of food labels is of interest to 80% of respondents, although the fibre content is not of interest for 43% of respondents. The vast majority (90%) of respondents have the notion that fibre intake contrib- utes to the prevention and treatment of diseases. With this work it was concluded that the individuals in the survey reveal an insufficient level of knowledge about dietary fibre and that, although they give great importance to the role of fibres in treatment and prevention of diseases, the level of intake is too low.
- Volatile components of vine leaves from two Portuguese grape varieties (Vitis vinifera L.), Touriga Nacional and Tinta Roriz, analysed by solid-phase microextractionPublication . Fernandes, Bruno; Correia, Ana; Cosme, Fernanda; Nunes, Fernando; Jordão, AntónioThe purpose of this work was to study the volatile composition of vine leaves and vine leaf infusion prepared from vine leaves collected at 30 and 60 days after grape harvest of two Vitis vinifera L. species. Eighteen volatile compounds were identified by gas chromatography–mass spectrometry in vine leaves and in vine leaf infusions. It was observed that the volatile compounds present in vine leaves are dependent on the time of harvest, with benzaldehyde being the major volatile present in vine leaves collected at 30 days after harvesting. There are significant differences in the volatile composition of the leaves from the two grape cultivars, especially in the sample collected at 60 days after grape harvest. This is not reflected in the volatile composition of the vine leaf infusion made from this two cultivars, the more important being the harvesting date for the volatile profile of vine leaf infusion than the vine leaves grape cultivar.