Browsing by Author "Santos, Sandra"
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- Consumer study and sensorial evaluation of a newly developed spicy strawberry syrupPublication . Guiné, Raquel; Lima, Maria João; Pato, Lúcia; Correia, Ana Cristina; Gonçalves, Fernando; Costa, Elisa; Santos, SandraThe potential beneficial effects of strawberry allied to those of chilly in many aspects of human health lead to the development of a spicy strawberry syrup. The work included the development of the product, including formulation, processing and industrialization aspects, chemical and sensorial analyses as well as a consumer study, of which some will be analysed in the present manuscript. The sensorial evaluation was performed with a panel of 25 tasters, of which 17 were women and 8 men. The parameters evaluated using a hedonic scale were: visual aspect, colour, consistence, brightness, sweetness, strawberry taste, spicy taste, global appreciation. To characterization of the product a brief chemical analysis was made. The mineral content was determined by calcination at 550 ºC, the total soluble solids (mainly sugars) were determined by refractometry and the moisture by a halogen moisture analyser. In all characteristics evaluated in the sensorial analysis the medium punctuation was 4 (in a scale from 0 to 5), corresponding to Good. Despite the product being considered quite spicy, its acceptance was very good.
- Efeito da secagem na composição fenólica da pêra Rocha (Pyrus communis L.) de diferentes origens.Publication . Santos, Sandra; Guiné, Raquel; Barros, AnaA pera Rocha (Pyrus communis L.) é a principal cultivar produzida em Portugal, sendo habitualmente consumida em fresco. No entanto, a secagem da pera pode constituir uma oportunidade de desenvolvimento e possibilitar a oferta de produtos alternativos aos consumidores. Neste trabalho, estudou-se o efeito de duas temperaturas de secagem (40 e 60ºC) sobre os teores de fenóis totais e de actividade antioxidante. Para isso foram usadas peras provenientes de 5 localidades diferentes. No caso dos fenóis totais, os resultados mostraram que as principais diferenças ocorreram com a secagem a 60ºC. Relativamente à actividade antioxidante, ambas as secagens originaram diminuições acentuadas dos valores, relativamente às peras analisadas em fresco.
- Effect of drying temperatures on the phenolic composition and antioxidant activity of pears of Rocha variety (Pyrus communis L.)Publication . Santos, Sandra; Guiné, Raquel; Barros, AnaThe interest about phenolic compounds and antioxidant activity has been increasing in recent years, mainly due to their beneficial effects on human health, focusing on many different food products. In this way, and since pears are an important source of dietary intake of phenolic compounds with antioxidant activity, this work was done to evaluate the phenolic content and antioxidant activity of pears of cv. Rocha from five different locations and submitted to drying at different temperatures (40 and 60 C). Although the amounts of phenolic compounds are not very much influenced by drying, the antioxidant capacity does suffer a very marked decrease with drying at both temperatures, when compared to that of the fresh pears. The HPLC analysis of the phenolic extracts allowed identifying some phenolic compounds present in the pears, such as arbutin, gallic acid, chlorogenic acid, syringic acid, protocatechuic acid, catechin and epicatechin. From the results obtained in this study it was concluded that the greatest variations occurred in the peel of the pears, as compared to the corresponding pulps. Furthermore, it was possible to observe that while total phenols and ortho- diphenols do not seem to be very affected by drying, the antioxidant capacity suffers a great decrease with drying, being this effect more pronounced when the drying tem- perature is increased.
- Food product development: whey cheese with pumpkin jamPublication . Guiné, Raquel; Costa, Elisa; Santos, Sandra; Correia, Ana Cristina; Correia, Paula; Pato, LúciaIn Portugal a popular desert is whey cheese with pumpkin jam. However, these two products are only sold separately. Having in mind that the production of a combination of these two would be potentially interesting for new food commercializing, studies were conducted on the development of this new food product. A sensorial evaluation and a consumer study were conducted to perceive how consumers accepted this new product. The sensorial evaluation consisted of a descriptive analysis, with a panel of 17 tasters. The parameters evaluated using five points hedonic scales were: homogeneity in colour, homogeneity of the product, milk aroma, intensity of aroma, intensity of taste, salty taste, milk taste, sweetness, consistency and presence of granules. The results of the classification given to the different parameters evaluated in the sensorial analysis showed that only the salty taste received a classification of 2 (in a scale of 1 to 4), whereas all the others had 4 or 5, indicating that the panellists appreciated the product. Regarding the consumer study, this was performed by applying questionnaires to 100 persons. The results showed that almost 60 % of the enquired referred liking whey cheese with pumpkin jam. As to the frequency of consumption, the majority does it monthly, but there is still a good deal of people who do it daily. From the results obtained, it can be inferred that this product can be a successful innovation in the Portuguese dairy industry.
- Influence of Drying on the Properties of Pears of the Rocha Variety (Pyrus communis L.).Publication . Santos, Sandra; Guiné, Raquel; Barros, AnaRocha pear (Pyrus communis L.) is the main cultivar produced in Portugal, usually consumed in fresh. However, the drying of the pear can be an oppor- tunity for development and enables the provision of alternative products to consumers. This work evaluates the effect of drying on some chemical and physical properties of pears of the Rocha variety. Furthermore, the origin of the pears was also a variable studied. For the completion of this work, pears from five different locations were analysed in fresh and after convective air drying at two different temperatures, 40 and 60°C. The properties analysed were dimensions of pears in terms of height and diameter, total solids content, acidity, maturation index, processing yields, colour and textural attributes. The results showed that the peel had lower acidity and higher maturation index, when compared to the pulp and that drying greatly reduced acidity, either in the pulp or in the peel. However, this variation was not influenced by the drying temperature. With respect to colour, total colour differences between 25 and 50 were observed (for the dried pears in relation to the fresh) and in this case increasing the drying temperature caused evident variations in the peel but not in the pulp. As to the textural attributes, hardness and chewiness were the ones that showed the higher changes with drying, increasing considerably with drying temperature.
- Influence of temperature on textural properties of Rocha pear (Pyrus communis L.) from different sourcesPublication . Santos, Sandra; Guiné, Raquel; Barros, A.‘Rocha’ pear is the main pear cultivar produced in Portugal and is important in other countries. It is a traditional product, classified as PDO (protected designation of origin). Most pears are consumed directly providing sugars, vitamins, organic acids, polyphenols, minerals and other nutrients. Some are also used for the preparation of fresh juice, canned beverages, alcoholic beverages, jellies and jams. Drying is an efficient way of preserving foods due to the significant reduction in water activity, thus inhibiting microbial growth and undesirable enzymatic modifications. Furthermore, it facilitates handling, storage and transportation, and avoids the use of expensive cooling systems. In this work, pears of the variety Rocha harvested at different orchards (four of the Western region and one of the “Beira Baixa”) were studied, fresh and dehydrated at two temperatures, 40 and 60 ºC, to determine and compare their texture attributes. The texture properties were evaluated by the method of texture profile analysis (TPA), using a texturometer, TE.XT.Plus Stable Micro Systems. The texture parameters evaluated were: hardness, adhesiveness, cohesiveness, elasticity and chewiness. The TPAs were obtained for samples of pears from the different origins analyzed in different orientations, and with or without the skin. In order to characterize each set of pears in relation to their maturation state, their acidity and soluble solids contents were determined, and the maturation index was then calculated.
- Sugar composition of Rocha pear (Pyrus communis L.) – Influence of drying treatmentsPublication . Santos, Sandra; Guiné, Raquel; Barros, AnaRocha Pear (Pyrus communis L.) is the main cultivar produced in Portugal, and is classified as Protected Designation of Origin (PDO). Pear production represents a significant economic activity in Portugal (c.a. 190.000 tonnes per year), and the cultivar Rocha represents 95% of the National Product [1]. The pear contains sugars, vitamins, organic acids, polyphenols and minerals in considerable concentrations [2]. Pears are, usually, eaten fresh when ripe. However, the increase in the supply of processed products, particularly subjected to drying [3], may provide an opportunity for development and enable the provision of alternative products to consumers. The drying of fruits is a very ancient practice for food preservation still in use nowadays, once the process significantly reduces water activity [4]. In this work, pears of the variety Rocha harvested at different orchards (five different origins) were studied, fresh and dehydrated at two temperatures, 40 and 60 ºC, to determine and compare their sugar composition. This determination was made separately to the pulp and peel from each location. The results showed that pulps contained a higher amount of sugars (6-15%) than peels, both fresh and dried. Additionally, it was possible to verify that the drying treatment caused a reduction (35-50%) in the total amount of sugars. Sugar analysis showed that the relative composition of fresh pulps and peels was similar, both composed mainly by mannose, followed by sorbitol and glucose. The drying process reduced glucose levels and increased the relative amount of mannose in pulps, while sorbitol and manose increased in peels.
- Variação de propriedades de textura de pêra Rocha de diferentes proveniências.Publication . Santos, Sandra; Guiné, Raquel; Barros, AnaA pêra Rocha (Pyrus communis L.) é uma cultivar produzida em Portugal, com grande expressão nos mercados Português e internacional. É um produto tradicional classificado como Denominação de Origem Protegida (DOP), sendo portanto a sua produção e comercialização regulamentada. Devido ao facto de ter um bom potencial de armazenamento, é possível a sua distribuição para o mercado durante quase todo o ano, sendo este um aspecto importante que a diferencia competitivamente em relação a outras variedades (1). De entre os atributos de qualidade que caracterizam qualquer alimento, e a pêra em particular, a textura assume um papel fundamental, sendo um atributo sensorial de grande relevância para a aceitação do alimento pelo consumidor, em conjugação com a aparência e o sabor (2). É essencialmente uma experiência humana, que resulta da nossa interacção com o alimento. A textura caracteriza-se por um conjunto de propriedades físicas que são consequência da estrutura interna do material, que por sua vez é determinada pelas interacções moleculares dos seus constituintes. Os alimentos no geral, e as peras em particular, apresentam diferentes propriedades de textura, que derivam das diferenças inerentes à variedade, ao estado de maturação e às condições de produção (solo, clima, entre outras) (3). Neste trabalho, são objecto de estudo as peras da variedade Rocha no estado fresco, colhidas em diferentes pomares (quatro da região do Oeste e um da região da Beira Baixa), de forma a determinar e comparar entre si os respectivos atributos de textura. As propriedades de textura foram avaliadas pelo método de análise do perfil de textura (TPA), utilizando como instrumento de medida um texturómetro, TE.XT.Plus da Stable Micro Systems. Os parâmetros de textura avaliados foram a dureza, a adesividade, a coesividade, a elasticidade e a mastigabilidade. Nos lotes de peras das diferentes proveniências foram obtidos os TPAs em amostras obtidas para diferentes orientações, e incluindo ou não a casca. No sentido de caracterizar cada lote de peras no que respeita ao seu estado de maturação, foram feitas análises para determinação do teor de sólidos solúveis e teor de acidez, sendo o índice de maturação calculado como a razão entre estas duas propriedades. Dos resultados obtidos foi possível observar algumas variações nas propriedades de textura em função da proveniência dos lotes, nomeadamente entre os da região do Oeste e o da região da Beira Alta.