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Guine R.P.F.,Polytechnic Institute of Viseu | Almeida C.F.F.,ESAV | Correia P.M.R.,Polytechnic Institute of Viseu
Journal of Food Measurement and Characterization | Year: 2014

The evaluation of some physical and chemical properties was done in order to investigate the effects of storage in hazelnuts, under certain conditions of temperature, relative humidity and packaging. The fruit samples used were original from Spain, Portugal and Turkey. The storage of the nuts lasted for a month and a half, and the conditions tested were: at room temperature; at 30 and 50 °C without control over relative humidity of the air; 30 and 50 °C with relative humidity of 90 %, refrigeration and freezing. The two types of plastic package tested were low density polyethylene (LDPE) and linear low density polyethylene The water activity was measured by a hygrometer; moisture by oven drying until constant weight, colour with a colorimeter and texture with a texturometer. From the results obtained it was concluded that for a good preservation of the hazelnuts it must be chosen the LDPE type of package and with respect to storage conditions it should be done at room temperature, or alternatively in refrigeration or freezing. © 2014 Springer Science+Business Media New York.

Guine R.P.F.,Polytechnic Institute of Viseu | Almeida C.F.F.,ESAV | Correia P.M.R.,Polytechnic Institute of Viseu | Mendes M.,Polytechnic Institute of Coimbra
Food and Bioprocess Technology | Year: 2015

The present work assessed the influence of different factors on some physical and chemical properties of nuts. The factors evaluated were the presence or absence of the inner skin, geographical origin, storage conditions (ambient temperature, in a stove at 30 and 50 °C, in a chamber at 30 and 50 °C and 90 % RH, refrigerated and freezing) and type of package (none, low density polyethylene and low density polyethylene). The fruits studied were almonds, hazelnuts and walnuts from different countries. The properties measured were moisture content, water activity, colour coordinates (L*, a* and b*) and texture parameters (hardness and friability). Experimental data were modelled using neural networks. The results showed that the almonds from Spain and Romania had aw greater than 0.6, and therefore, its stability was not guaranteed, contrarily to the other samples that presented values of aw lower than 0.6. The colour coordinate lightness varied from 40.60 to 49.30 in the fresh samples but decreased during storage, indicating darkening. In general, an increase in hardness and friability was observed with the different storage conditions. Neuron weight analysis has shown that the origin was a good predictor for moisture content and texture; whereas, the storage condition was a good predictor for aw and colour. In conclusion, it was possible to verify that the properties of nuts are very different depending on origin; they are better preserved at lower temperatures and the type of package used did not impact the properties studied. © 2015, Springer Science+Business Media New York.

Guine R.P.F.,Polytechnic Institute of Viseu | Henriques F.,ESAV | Barroca M.J.,Polytechnic Institute of Coimbra
Journal of Food Measurement and Characterization | Year: 2014

This work aimed at determining the properties of cucumber exposed to convective air drying and freeze-drying. The samples were analysed in terms of colour, texture, chemical properties (moisture content, fibre, ash, vitamin C and sugars), phenolic compounds and antioxidant activity in fresh and after drying. The trials in the convective chamber were done at 40 and 60 °C, in the drying tunnel at 60 °C and in the freeze dryer at -50 °C. The results showed that the antioxidant activity and the phenolic compounds were not affected by any of the drying treatments tested, since the values were quite similar in the fresh product as compared to the dried cucumbers. With respect to colour, the freeze drying treatment was identified as the one originating less colour change, when compared with the colour of the fresh product. Finally, texture was less affected by drying in the chamber at 40 °C and freeze drying. © 2014 Springer Science+Business Media New York.

Davim S.,ESAV | Andrade S.,ESAV | Oliveira S.,ESAV | Pina A.,ESAV | And 3 more authors.
International Journal of Fruit Science | Year: 2015

In this work, fruit-derived products were enriched with a fructooligosaccharide, inulin, obtained from tubers of Jerusalem artichoke (Helianthus tuberosus). The products developed included juices and jams from various fruits and were analyzed in terms of chemical, microbiological, and sensorial properties right after production and again after storage. The comparison of the results before and after storage would allow establishing the conservation ability of the products developed. The results obtained allowed concluding that the products obtained contained a high content of inulin, which is a prebiotic compound with important benefits for gut health. © , Copyright © Taylor & Francis Group, LLC.

Davim S.,ESAV | Patkai G.,H+ Technology | Monspart-Senyi J.,H+ Technology | Kokai L.,H+ Technology | And 2 more authors.
Current Nutrition and Food Science | Year: 2014

The aim of this work was to develop products derived from fruits enriched with inulin, which is a carbohydrate seen as a functional or nutraceutical nutrient, consisting of fructose, found naturally in various vegetables, such as the Jerusalem artichoke. The first step of this work was to obtain fruit juices as well as compotes with inulin from Jerusalem artichoke. The second part of the work included the determination of some chemical, microbiological and sensorial analyses to the products. After one month of storage, the products were submitted to all the analyses again, to assure their stability. The results obtained allowed concluding that the products prepared could be considered as functional foods due to the high content of inulin and low percentage of fructose that they contained. © 2014 Bentham Science Publishers.

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