Browsing by Author "Fonseca, Mariana"
Now showing 1 - 6 of 6
Results Per Page
Sort Options
- Analysis of Textural Properties of Gluten Free BreadsPublication . Correia, Paula; Guiné, Raquel P. F.; Fonseca, Mariana; Batista, L.Bread is one of the most important gluten-free foods, and it is usually connected with crumbling texture, poor colour, low volume, unsatisfactory taste and a short shelf-life, probably due to the lack of the viscosity network formed by gluten. Thus, some defects of gluten- free bread are related with inefficient gas retention and expansion during dough leavening, which results in a reduced volume and low crumb softness of the breads. The current challenge is for the industry to overcome these limitations. Furthermore, the texture is a characteristic that depends on the structure of the food, but also on the complex oral manipulation that aims to grind the food. In the present work the textural properties were analysed in breads made with special flours without gluten produced industrially, and the reproducibility of the results between breads from different batches was also evaluated. Two formulations of gluten-free flour were tested, provided by Germen (Portugal) (designated as A) and Credin (Denmark) (designated as B), and were also produced samples of bread with wheat flour type 65 (sample called Control), produced by CEREALIS (Portugal) - designated as A, B and Control samples, respectively. For analysis of the textural characteristics, a texturometer was used and perforation and compression tests were performed. The properties measured by the perforation test were: crust firmness, crumb firmness, adhesiveness, and stickiness. In the compression test, the characteristics evaluated were: hardness, elasticity, cohesiveness, resilience and chewiness. To evaluate the reproducibility, the breads were produced in four different batches, for each type of bread (A, B and Control), to assess whether the characteristics were maintained on the different days of manufacture. The results obtained for the perforation test showed that the loaves produced with gluten-free flours are less firm (in the crust and in the crumbs) and less adhesives when compared to bread made with type 65 flour (with gluten). Regarding stickiness, it can be said that there are not many apparent differences between the breads analysed, however bread B is more similar to Control bread. Bread A has a greater discrepancy between the top and the bottom in terms of stickiness, being more intense on the top of the bread. The compression tests showed that in the crumb the values are identical in all studied samples, including the control sample. However, when analysing the complete slice, it appears that samples A and B are considerably less hard than the Control, due to the crust contribution. The gluten-free breads presented lower resilience than the Control sample, with Sample B showing the highest concordance between the crumb and the complete slice. Moreover, the results showed both gluten-free breads had similar elasticity and chewiness values, both for the crumb and for the whole slices, and higher than the wheat bread. Regarding the reproducibility of the results, it was possible to observe that the perforation tests are preferable to those of compression, and that on the other hand the samples made with the flour without gluten type B are more uniform between batches. The results obtained in this study showed that the type of flour, its composition and the presence or absence of gluten significantly influence the texture of the breads produced. Breads made with gluten-free flours were less firm on the crust and crumbs when compared to wheat bread. On the other hand, gluten-free breads tend to be less sticky and slimy. Moreover, the two tests to evaluate the texture proved to be complementary, since they allow to evaluate different characteristics, and thus obtain a more complete profile of textural characteristics of the breads. The reproducibility of the results was higher for perforation tests compared to compression tests, and on the other hand the samples manufactured with type B gluten-free flour showed to be more constant in their texture characteristics, when different batches of bread were compared.
- Avaliação da textura de pães sem glútenPublication . Guiné, Raquel; Fonseca, Mariana; Batista, Luís; Correia, PaulaNo presente trabalho foram analisadas as propriedades de textura em pães fabricados com farinhas especiais sem glúten, tendo ainda sido avaliada a reprodutibilidade dos resultados entre pães provenientes de diferentes lotes. Para tal, foram testadas duas formulações de farinha sem glúten, foram fornecidas pelas empresas GERMEN (Portugal) e CREDIN (Dinamarca), tendo ainda sido produzidas amostras de pão com farinha comum tipo 65, produzida pela empresa CEREALIS (Portugal) (amostra controlo). Para análise das características da textura recorreu-se a um texturómetro, tendo sido realizados ensaios de perfuração e compressão. Os resultados obtidos revelaram que os pães produzidos com farinhas sem glúten se apresentam menos firmes (na crosta e no miolo) e menos adesivos, quando comparados com o pão fabricado com farinha tipo 65 (com glúten). Em relação à reprodutibilidade dos resultados, foi possível observar que os testes de perfuração são preferíveis aos de compressão, e que por outro lado as amostras fabricadas com a farinha sem glúten tipo B são mais uniformes entre lotes.
- Gluten-free bread: a case studyPublication . Correia, Paula; Fonseca, Mariana; Guiné, RaquelPhysicochemical and sensorial characteristics of a possible commercial gluten-free bread (GFB) made with a new gluten-free flour were studied, as compared to a regular wheat bread, which was also analysed as Control sample. Results show that GFB presented high values of moisture and water activity, 36.56% and 0.96. This bread presented high density (0.38 g/ cm3) comparing to regular bread (0.25 g/ cm3), being these results reinforced by image analysis of alveoli. GFB was whiter, with less color intensity, meaning that a* and b* color parameters were lower than control, which was confirmed by sensorial evaluation results. GFB was soft and easily chewable (75.0 N and 70.0 N, respectively for hardness and chewiness), which, once again, was corroborated by the sensorial results. The overall assessment done by the consumer panellist to GFB was 4.1 (on a scale from 1 to 10), while the control bread presented 5.5. It could be concluded that the new flour formulation is suitable for GFB production, with characteristics comparable with the regular bread
- Health-enhancing? Products: development of yogurts containing ingredients with functional propertiesPublication . Lemos, Edite Teixeira de; Guiné, Raquel; Ferreira, Ana C.; Aparício, Daniela; Marques, Hugo; Fonseca, Mariana; Loureiro, SaraINTRODUCTION The importance of yogurt as part of a balanced and healthy diet is recognized by regulatory authorities and scientific institutions in most countries. According to the Portuguese National Statistics Institute, there was an increase of 38% in the value of dairy sales in only four years. In addition, a study carried out by the Portuguese Society of Nutrition and Food Sciences reported that 26.8% of Portuguese adults consumed yogurts daily, ranging from 19% in the elderly to 35% in adults up to 30 years. Hence, this market represents a good opportunity to development new healthy yogurts. OBJECTIVES It was intended to develop yoghurts with improved health functionalities different than those already existing on the market, by adding several combinations of ingredients with established biological activities. METHODS Laboratorial experiments were done testing various combinations and different proportions of ingredients, to establish those that had potential for consumer acceptance. The ingredients tested included unconventional vegetables, fruits, herbs or seeds. After the laboratorial experiments with the formulations, those that resulted better were selected for a sensorial evaluation by an untrained panel simulating the consumers. Four final products were developed, corresponding to different combinations of ingredients, and having been identified with the four seasons of the year (Winter, Spring, Summer, Autumn). The final products were analysed as to their physico-chemical composition by using established methodologies. The nutritional information and energetic value was also evaluated. RESULTS The Winter yogurt possesses thermogenic and satiating properties and the ingredients used were apple, chia, cinnamon and ginger. The Spring yogurt presents properties capable of regulating intestinal transit, loss of appetite and is diuretic. The ingredients selected were pineapple, celery and mint. The Summer yogurt has antioxidant properties, regulates intestinal transit and diuresis. The ingredients included linseed, parsley, carrot, passion fruit and orange. The Autumn yogurt has diuretic and thermogenic properties. The ingredients used in its confection were watercress, pear and ginger. Protein, fibre and lipids varied, respectively, in the ranges 2.2-2.7, 0.4-1.5 and 0.5-0.7 g/100 g. The energetic value varied from 36 to 92 kcal/100 g and the calcium from 64 to 100 mg/100 g. CONCLUSIONS It is important that the food industry seeks to meet the needs of the consumers, which are more and more devoted to healthy eating practices, and who like to find also new and stimulating products to buy. The developed products were formulated to meet these challenges, and are believed to successfully enter the dairy products market because the evaluations of the sensorial panel were very positive. Hence, they have potential to be launched as a potential industrial opportunity in the line of yogurts with improved healthy functionalities. Furthermore, the putative effects of yogurt on the modulation of the gut microbiota and the prevention of obesity and cardiometabolic diseases will make them a successful new product.
- Iogurtes detox: o prazer do bem-estar a 4 estaçõesPublication . Fonseca, Mariana; Loureiro, Sara; Esteves, Sabrina; Guiné, Raquel; Teixeira de Lemos, Edite
- Production of a new gluten-free bread and comparison with a regular wheat breadPublication . Correia, Paula; Fonseca, Mariana; Batista, Luis; Guiné, RaquelO principal objetivo deste trabalho foi a avaliação das caraterísticas físico-químicas e sensoriais de um novo pão sem glutén (GFB), comparando-o com o pão de trigo usualmente consumido (RWB). O pão sem glutén foi produzido a partir de uma farinha de mistura de uma fábrica nacional. Foram avaliadas a atividade da água (aw), o teor de humidade e de glutén, a textura, cor, densidade e as caraterísticas alvéolares, bem como as caraterísticas sensoriais. Existiram algumas diferenças entre o GFB e o RWB, principalmente na densidade, na elasticidade, na mastigabilidade, e também nas características alvéolares. No entanto, as coordenadas da cor, a humidade e a aw apresentam resultados semelhantes para ambos os pães avaliados. Os resultados da análise sensorial mostraram algumas diferenças, principalmente na textura e no flavour. A avaliação global foi a mesma para os dois pães, 5.6 pontos, sendo um resultado promissor. Foi também avaliada a estabilidade das caraterísticas dos pães entre diferentes lotes, tendo sido avaliados 4 lotes independentes de GFB. De um modo geral, e considerando só as propriedades avaliadas, pode dizer-se que o GFB apresentou bons resultados e promissores. Deste modo, a farinha usada pela empresa Portuguesa é adequada para a produção de GFB, originando um pão com qualidade, com benefícios para a saúde.