Evaluation of browning rate of quince at ambient exposure

Since quince is a fruit relatively susceptible to browning, in the present work it was evaluated the colour of the quince over time of exposure to the atmospheric air. The colour of the fresh pulp was assessed using a handheld tristimulus colorimeter using the CIELab colour coordinates: L*a*b*. These Cartesian coordinates were then used to calculate the polar or cylindrical coordinates: value, hue angle (º) and chroma. At each instant, ten measurements of colour were made, and to evaluate the colour change, measurements were repeated in the same samples after every 5 minutes, over a period of two hours. The results obtained for the medium values of the cylindrical coordinates in the freshly cut quince were found to be: value = 7.80, chroma = 31.78 and Hue = 92.28º, being these values determined right after cutting. Total colour difference (TCD) was calculated having the values of the Cartesian coordinates of the freshly cut quince as reference. In relation to the colour change, the values for TCD were 0.00, 26.35, 30.41, 31.81 and 32.39, respectively for times 0, 30, 60, 90 and 120 minutes, indicating a faster rate initially and a tendency for stabilization towards the end of the period analyzed

Effect of drying on the physical properties of quince

This study aimed at evaluating the textural properties of quince in fresh and after drying at different conditions. In parallel, colour was also measured to evaluate how the visual aspect of the product changed with drying. The experiments were done in a tunnel drier, at different temperatures, from 30 to 60ºC, and different air velocities, varying in the range 0.7 to 1.2 m/s. The colour coordinates of the fresh quince were: L* = 78.02±0.86, a* = - 1.27±0.32 and b* = 31.75±1.68. These values indicate that the samples were bright, because L* was closer to 100 than to 0. Furthermore, it can be seen that quince was greenish, although very slightly and strongly yellowish. With drying, the samples became darker and redness was intensified, as a result of browning. In relation to the textural properties in fresh, the values were: hardness = 48.46±6.47 (N), springiness = 74.86±5.17 (%), cohesiveness = 0.75±0.06, resilience = 0.47±0.08 and chewiness = 27.23±4.06 (N). Furthermore, it was observed that drying, regardless of the conditions, induced an important hardening, increasing hardness and diminishing springiness

Environmental aspects of Hungarian consumers’ food choice

Enhancing of environmental awareness is not just a local aim, is a global priority that will contribute to ensuring a sustainable future. As one of the Sustainable Development Goals of the United Nations as well as among the key areas of the FOOD2030 priorities, sustainable and healthy diets have to be promoted both locally and globally. Even the environmental aspects are not the leading elements of the Hungarian consumers’ food choice (Törőcsik, 2009; Hofmeister-Tóth et al., 2011) and the rate of the most committed consumer group to sustainability is almost 8% (Lehota et al., 2014), the level of awareness is constantly rising (Dudás, 2011; Gulyás, 2017). In order to support this process identification of the intervention points is essential. Thus the aim of the present paper was to examine the appearance of the environmental factors in Hungarian consumers’ food choice decisions and their relation to the level of healthy lifestyle.info:eu-repo/semantics/publishedVersio

Experimental Determination and Computer Fitting of Desorption Isotherms of D. Joaquina Pears

Desorption isotherms at different operating temperatures provide valuable information for the design and control of drying processes. In the present work the desorption isotherms of pears are determined according to two equivalent forms of the GAB model at temperatures of 20, 25 and 30°C. These cover the range of summer average daily temperatures in Portugal, when the solar drying of pears is carried out. Two different computer fitting methodologies are used, namely, Ordinary Least Squares (OLS) and Orthogonal Distance Regression (ODR), in order to evaluate the above mentioned forms of the GAB model.http://www.sciencedirect.com/science/article/B8JGD-4RTVWGX-2/1/6c903cd58bc08221bbe47d10c3f56d0

Healthy bread as an alternative to traditional bread

Today, bread is part of the culture and eating habits of most people and can be considered one of the most consumed foods in the world. The bread is made from a simple mixture of flour, water, salt and yeast, and it is an extremely versatile food and with a very good digestibility. Since it was first produced for thousands of years, it has undergone changes both in terms of production methods and in terms of its constitution, thus giving place nowadays to a wide variety of breads available on the market. The objectives of this study were to compare the sensory and nutritionally attributes of a special healthier bread, ―Pão São‖, which is a recent product in the Portuguese market. Nutritionally this type of bread turned out to be a food with high nutritional value, with a low salt content (0.4%, about half of traditional bread), and being a good source of omega-3 (0.67%), fibre and protein when compared with the traditional bread. These differences are mainly due to the wide variety of raw materials selected to the preparation of this bread, including the mixture of flour (wheat flour type 150 and 65 and rye flour type 70), oatmeal, sunflower and linseed seeds, soy, fish oil extracts rich in omega 3, malt and milk protein. From the results of the sensory analysis, conducted by a panel of 40 untrained tasters aged 7 to 63 years, it was found that the traditional breads from the region closest to the marketing of healthy bread were preferred by the tasters, especially for their wood and bread flavour, as well as elasticity. The healthy bread was evaluated as a denser bread, with a more intense fermented flavour. With this work it was concluded that the healthy bread is a nutritious and healthy bread, being currently recommended by the Portuguese Foundation of Cardiology. However from the sensory point of view, consumers still slighly prefer the traditional bread

Pão são, uma alternativa ao pão tradicional

Hoje em dia o pão faz parte da cultura e dos hábitos alimentares da maioria dos povos, podendo considerar-se um dos alimentos mais consumidos do mundo. O pão é feito a partir de uma mistura simples de farinha, água, sal e fermento, sendo um alimento extremamente versátil e com uma enorme digestibilidade [1]. Desde que foi produzido pela primeira vez há milhares de anos, foi sofrendo evoluções quer ao nível dos métodos de produção, quer ao nível da sua constituição encontrando-se nos dias de hoje uma grande diversidade de pães no mercado. Os objectivos deste trabalho foram comparar nutricionalmente e sensorialmente um pão classificado como especial, o Pão São, um produto recente no mercado Português. Nutricionalmente o Pão São revelou ser um pão com elevado valor nutricional, apresentando um baixo teor de sal (0.4%, cerca de metade do pão tradicional), sendo uma boa fonte de ómega 3 (0.67%), fibras e proteínas quando comparado com o pão tradicional. Estas diferenças devem-se sobretudo à grande variedade de matérias-primas seleccionadas na elaboração do Pão São, nomeadamente a mistura de farinhas (farinhas de trigo tipo 65 e 150 e farinha de centeio tipo 70), flocos de aveia, sementes de girassol e linhaça, soja, extractos de óleo de peixe rico em ómega 3, malte e proteína de leite. Dos resultados obtidos da análise sensorial, realizada por um painel de 40 provadores não treinados com idades compreendidas entre os 7 e os 63 anos, verificou-se que os pães tradicionais da região de comercialização mais próxima do Pão São foram os preferidos pelos provadores, destacando-se pelo seu sabor a lenha e a pão, e pela sua elasticidade. O Pão São foi avaliado como um pão mais denso, apresentando um sabor mais intenso a fermentado. Com a realização deste trabalho foi possível concluir que o Pão São é um pão nutritivo e saudável, sendo actualmente recomendado pela Fundação Portuguesa de Cardiologia. No entanto sobre o ponto de sensorial o consumidor aprecia e prefere o pão tradicional

Customer knowledge and behavior on the use of food refrigerated display cabinets: A Portuguese case

This article presents a study on customer knowledge and habits regarding the use of refrigerated display cabinets (RDC). The study was carried out on a sample of Portuguese retail stores’ customers, using a questionnaire survey available through an Internet platform. The sample consisted of 136 individuals, who voluntarily participated in the study. Questions included the characterization of the sociodemographic population involved. The questionnaire included different questions to related with RDC, namely customer knowledge about the appearance of each RDC equipment, questions to evaluate the respondents’ perception about the advantages and disadvantages related to open or glass-door closed RDC, questions to assess the participants’ habits and behavior when purchasing food products from glass-door closed RDC (frequency and duration of door open), questions to characterize the consumers’ habits on purchasing food products from RDC, and also questions to characterize the consumers’ shopping attitudes in the context of the COVID-19 pandemic, caused by SARS-CoV-2. The results seem to indicate that customers prefer closed RDC; for example, 61.8% of participants prefer products preserved in glass-door closed RDC, against 6.6% that admit to preferring products preserved in open RDC. Therefore, we can deduce that the existence of doors does not appear to be an obstacle to purchasing food products. Regarding the use of glass-door closed RDC, 80.1% of the participants say they just open the door once, and 53.7% of the costumers believe they keep the door open in the interval [4‒6 s]. This indicates that Portuguese customers are quite well informed about food safety issues and seem to follow assertive attitudes when purchasing food products from RDC. This study reinforces the benefits of replacing open RDC by closed glass-doors allowing significant energy savings.info:eu-repo/semantics/publishedVersio

Phenolic compounds and antioxidant activity in red fruits produced in organic farming

In this work were studied three red fruits (raspberry, gooseberry and blueberry) produced in organic mode, to evaluate the variations in the content of phenolic compounds and antioxidant capacity along maturation. The phenols were extracted from the fruits with two solvents (methanol and acetone) and were quantified by the Folin-Ciocalteu method. The antioxidant activity was determined with two methods (HPPH and ABTS). Furthermore, HPLC was used to identify and quantify some phenolic compounds present in the fruits analyzed. The results showed that the total phenolic compounds in all fruits decreased along maturation, either in the methanol or acetone extracts (23 % and 20 % reduction, on average, for methanol and acetone extracts, respectively), although in methanol extracts the levels of phenolic compounds were always higher (0.54 and 0.21 mg GAE/g). The blueberry showed higher level of total phenolics in methanol extract (average 0.67 mg GAE/g), while in the acetone extract it was gooseberry (average 0.31 mg GAE/g). At the end of maturation, all fruits studied had similar values of antioxidant capacity as determined by DPPH method (0.52 mmol Trolox/g). For the ABTS method, blueberries showed higher values of antioxidant activity (6.01 mmol Trolox/g against 3.01 and 2.66 mmol Trolox/g, for raspberry and gooseberry, respectively). Furthermore, the HPLC analysis allowed to identify monomeric anthocyanins and phenolic acids in the three fruits studied

Phenolic compounds and antioxidant activity in red fruits produced in organic farming

In this work were studied three red fruits (raspberry, gooseberry and blueberry) produced in organic mode, to evaluate the variations in the content of phenolic compounds and antioxidant capacity along maturation. The phenols were extracted from the fruits with two solvents (methanol and acetone) and were quantified by the Folin-Ciocalteu method. The antioxidant activity was determined with two methods (HPPH and ABTS). Furthermore, HPLC was used to identify and quantify some phenolic compounds present in the fruits analyzed. The results showed that the total phenolic compounds in all fruits decreased along maturation, either in the methanol or acetone extracts (23 % and 20 % reduction, on average, for methanol and acetone extracts, respectively), although in methanol extracts the levels of phenolic compounds were always higher (0.54 and 0.21 mg GAE/g). The blueberry showed higher level of total phenolics in methanol extract (average 0.67 mg GAE/g), while in the acetone extract it was gooseberry (average 0.31 mg GAE/g). At the end of maturation, all fruits studied had similar values of antioxidant capacity as determined by DPPH method (0.52 mmol Trolox/g). For the ABTS method, blueberries showed higher values of antioxidant activity (6.01 mmol Trolox/g against 3.01 and 2.66 mmol Trolox/g, for raspberry and gooseberry, respectively). Furthermore, the HPLC analysis allowed to identify monomeric anthocyanins and phenolic acids in the three fruits studied

Evaluation of phenolic compounds and antioxidant activity of blueberries and modelization by artificial neural networks

The study aimed at evaluating the influence of different production conditions, conservation and extraction procedures on the total phenolic compounds and antioxidant activity of blueberries by DPPH and ABTS methods. The production factors considered were origin, altitude of the farm location and age of the bushes. The conservation conditions considered were freezing as opposed to the fresh product. The extraction procedures included two different solvents and two orders of extraction. The data analysis was carried out by training artificial neural networks to model the data and extract information from the model. The results obtained revealed that the type of extract and the order of extraction influenced the concentrations of phenolic compounds as well as the antioxidant activity of the different samples studied. Also the origin of the farms from where the blueberries were harvested significantly influence those properties, showing that the blueberries from Oliveira do Hospital had less phenolic compounds and lower antioxidant activity. Also older bushes at higher altitudes seem to produce berries richer in these properties. Regarding conservation, no influence was observed for phenols but a slight influence could be detected for antioxidant activity.info:eu-repo/semantics/publishedVersio