Conservação da castanha: o presente e o futuro

A castanha (Castanea sativa) é um fruto com uma elevada importância económica em Portugal. Devido ao seu elevado potencial comercial, o governo Português tem incentivado a produção de castanha, sendo considerada uma fileira estratégica no Plano de Desenvolvimento Rural pelo Ministério da Agricultura, Desenvolvimento Rural e Pescas. Dada a sua importância a garantia da qualidade comercial deste fruto é essencial e em particular para a região de Trás-os-Montes. A castanha é um fruto perecível já que mantém a sua qualidade comercial e turgescência durante um curto período após a colheita. Como produto sazonal, tem que ser conservada, quer para ser vendida como produto fresco, quer para ser posteriormente processada. Nesse sentido, pretende-se referir o estado actual das tecnologias mais utilizadas na conservação da castanha e apresentar possíveis linhas gerais de acção a implementar no futuro

Conservação de castanha por irradiação

Preservação de castanha por irradiação para eliminação dos insectos pós-colheita, como alternativa à fumigação química e ao tratamento por águas quentes, não alterando as principais características do fruto, como a cor, sabor, textura e composição nutricional

Target specific post-harvest treatment by gamma radiation for the microbial safety of dried Melissa officinalis and Aloysia citrodora

This study aimed to assess a specific gamma radiation dose to be applied as a post-harvest process to guarantee the microbial safety of two medicinal plants, Melissa officinalis and Aloysia citrodora. Dried plants treated with gamma radiation indicated that a dose of 5 kGy could be applied as a post-harvest treatment process of M. officinalis and A. citrodora, assuring the microbial safety of dried medicinal plants and lowering the potentiality of deleterious effects on plants’ quality attributes. This will enhance the safety and quality of the dried plants to be used as raw materials in industrial applications.The authors are grateful to project PRODER nº 53515, AROMAP, for financial support of the work. The authors thank to “MaisErvas - Aromáticas e Medicinais” company for supplying the samples. C2TN/ IST authors gratefully acknowledge the FCT support through the RECI/AAG-TEC/0400/2012 and UID/Multi/04349/2013 projects.info:eu-repo/semantics/publishedVersio

Impact of gamma irradiation on nutritional composition and antioxidant activity of Aloysia citriodora Paláu and Melittis melissophyllum L.

Aloysia citriodora Paláu and Melittis melissophyllum L. are examples of plants that have been used for medicinal purposes as dietary supplements or infusions [1,2]. The incorporation of plant extracts/compounds in pharmaceuticals has been increasing. However, due to the high demand of the pharmaceutical industry for the use of raw materials with good microbiological quality, decontamination techniques should be applied. Irradiation arises as an alternative [3]. The aim of this work was to evaluate the effects of gamma irradiation (0 kGy – control, 1 kGy and 10 kGy) on nutritional value and antioxidant activity of A. triphylla and M. melissophyllum. The nutritional value was determined following official analysis methodologies; free sugars were analyzed by high performance liquid chromatography coupled to a refraction index detector (RI-HPLC), fatty acids by gas chromatography coupled with a flame ionization detector (GC-FID), and tocopherols by HPLC-fluorescence. The antioxidant properties of the infusions were evaluated through free radicals scavenging activity, reducing power and inhibiting of lipid peroxidation. In general, gamma irradiation protected fructose, trehalose, and the major fatty acids found in A. citriodora. Furthermore, the dose of 10 kGy protected oxalic, malic, and quinic acids, as also protein and ash levels and revealed the highest antioxidant activity for the majority of the assays. The dose of 1 kGy protected all isoforms of tocopherols detected in the plant. Regarding M. melissophyllum, it was concluded that the control sample (non-irradiated) showed the highest antioxidant activity, as well as the highest levels of -tocopherol. However, in general, it was observed that a dose of 10 kGy maintains the nutritional properties of the plant, such as protein and ash levels. Thus, we can conclude that irradiation is a decontaminating technique that does not interfere drastically with the chemical properties of the studied plants.Proder (Project nº 53514, AROMAP) and to Fundação para a Ciência e a Tecnologia (FCT, Portugal) for financial support to CIMO (strategic project PEst-OE/AGR/UI0690/2011). The authors are also grateful to “MaisErvas - Aromáticas e Medicinais” for samples providing

Flores comestíveis: múltiplas utilizações do mais belo da natureza

As flores comestíveis têm vindo a tornar-se cada vez mais populares, o que se torna claramente evidente pelo aumento de livros de receitas, artigos de revistas e sites sobre o tema, para além do crescimento da investigação científica relacionada com o seu potencial nutricional. O foco principal é a alta gastronomia, atraindo a atenção de gourmets e chefs.Projecto bilateral FCT – CNPq, Portugal/Brazil 2014-201

Castanea sativa shells and fruits: Compositional analysis by proton induced X-ray emission

Chestnut fruits, from Castanea sativa Miller species, have been previously characterized mainly to study the nutritional and biochemical parameters, with mineral contents receiving less attention from the researchers, although these minerals are essential for several mechanisms in human body. In this study, a detailed elemental compositional analysis was performed using Proton Induced X-ray Emission (PIXE) to characterize two varieties of Castanea sativa Miller chestnuts (Longal and Judia). This study comprises the composition of the outer shells (pericarp), inner shells (episperm) and the edible fruits. From our knowledge, this is the first time that the presence of up to 20 elements on the shells and the fruits are reported. Furthermore, by PIXE it was possible to quantify them, allowing significant improvements in the assessment of chestnuts composition. Essential and nonessential elements were quantified on a food item that is used mainly for human consumption but it is also incorporated in animal feeding.Authors acknowledge R. Pinheiro for sample preparation. This work was developed within the Coordinated Research Project D61024 ‘‘Development of New Applications of Machine Generated Food Irradiation Technologies’’ financed by the International Atomic Energy Agency (IAEA). IST authors gratefully acknowledge the FCT (Fundação para a Ciência e a Tecnologia) support through the UID/Multi/04349/ 2013 and UID/FIS/50010/2013 projects.info:eu-repo/semantics/publishedVersio

A comparative study between natural and synthetic antioxidants: Evaluation of their performance after incorporation into biscuits

Currently, the food industry is focused in replacing the use of synthetic by natural antioxidants. The present study focused on the use of fennel and chamomile extracts, rich in phenolic compounds, as natural antioxidants in biscuits and compared their performance with a synthetic antioxidant widely used, the butylated hydroxyl anisole (BHA). The complete nutritional profile, free sugars, fatty acids and antioxidant activity were determined immediately after baking and also after 15, 30, 45 and 60 days of storage. The results showed that the incorporation of natural and synthetic additives did not cause significant changes in colour or in nutritional value of biscuits when compared with control samples. Both natural and synthetic additives conferred similar antioxidant activity to the biscuits. Therefore, natural additives are a more convenient solution for consumers who prefer foods “free” from synthetic additives. Additionally, natural additives were obtained by aqueous extraction, an environment friendly and safe process.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER for CIMO (UID/AGR/00690/2013) and LSRE (Project UID/EQU/50020/2013) financial support, and C. Caleja (SFRH/BD/93007/ 2013) and L. Barros (SFRH/BPD/ 107855/2015) grants. The authors also thank Ms Clarinda Paixão, from Américo Duarte Paixão Lda, Portugal, for providing the plant samples.info:eu-repo/semantics/publishedVersio

Analytical methods applied to assess the effects of gamma irradiation on color, chemical composition and antioxidant activity of Ginkgo biloba L

The extracts from the leaves of Ginkgo biloba are widely used in medicines and food supplements in order to overcome different health problems. To provide decontamination, irradiation is a safe and effective technique, particularly suitable to be integrated in quality control of the postharvest samples. In this study, different analytical methods were applied to assess the effects of gamma irradiation (1 and 10 kGy) in G. biloba color, chemical composition and antioxidant properties. Irradiation preserved macronutrients, fatty acids, γ- and δ-tocopherols, fructose, trehalose, quinic and shikimic acids. In particular, 1 kGy protected α-tocopherol, oxalic and malic acids contents, while 10 kGy decreased α-tocopherol, glucose, sucrose, oxalic and malic acids level. Nevertheless, this dose was the most effective for antioxidant activity. Overall, 1 kGy would be the recommended dose to maintain nutritional profile of G. biloba, protect specific molecules and also increase antioxidant activity of infusion and methanolic extracts prepared from its leaves.The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) for financial support to CIMO (strategic project PEst-OE/AGR/UI0690/2011). The authors are also grateful to Clarinda Paixão, from Américo Duarte Paixão Lda, for samples providing

Gamma irradiation of chestnuts: dosimetric study and its influence in drying

Food irradiation is a process that has been regaining an increasing interest for different food products to increase shelf life, for disinfestation or sterilization. In industry the drying of chestnuts is used to produce other sub-products, such as flour. So far as we know this is the first time that the influence of gamma irradiation in drying behaviour of an european chestnuts variety was performed. First the dose rate distribution was measured in one of the four levels of a Cobalt-60 irradiation experimental chamber to evaluate the uniformity dose during the irradiation process. The corners of a rectangle with the sample dimensions were chosen, being used the chemical Fricke standard dosimeter for dose rate estimation and routine Amber Perspex during irradiations. The average dose rate for the irradited positions was 2.1 ± 0.8 kGy h–1 , and the ratio Dmax/Dmin was 2.5. Afterwards the chestnuts were subjected to different doses (0, 1, 3 and 6 kGy), and then dried in a forced convective oven at 50 oC. The moisture ratios for each irradiation dose, as well as the drying rates, were determined. The Page model was used to modelize the drying behaviour, obtaining adjusted R squares higher than 0.98. Only the falling rate period was detected. At begininng the drying rates were high, decreasing very fast till 2 h of drying, after that the rates practically did not change till the end of the process. For the irradiation doses up to 6 kGy, it was observed a slight difference between non-irradiated and irradiated fruits drying behaviour

Espectroscopia Raman na caracterização de alimentos: a castanha como exemplo

A castanha é um fruto sazonal mediterrânico, com uma importância económica significativa em algumas regiões, estando Portugal entre os 5 maiores produtores deste fruto na Europa, com um total superior a 20 000 ton. e um valor directo para os produtores de mais de 20 milhões de Euros. A comercialização e valorização deste fruto assentam sobretudo no seu calibre. Na indústria, a produção de subprodutos a partir da castanha, com maior valor acrescentado, como o “marron glacé” (castanha caramelizada), tem em conta não só o seu calibre como as diferentes variedades de castanhas. Diferentes variedades apresentam diferentes características físicas e químicas que facilitam o seu processamento industrial ou o inviabilizam, se esta não for a adequada. A possibilidade de utilizar ferramentas que permitam a sua fácil e rápida discriminação pode ser uma mais-valia para todo o sector, do produtor à indústria. Neste trabalho preliminar procurou-se ver até que ponto a Espectroscopia Raman permite (ou não) a discriminação de duas variedades de castanha da região de Trás-os-Montes, Portugal. Os resultados preliminares evidenciam modos vibracionais dos constituintes da castanha, nomeadamente amido. Relativamente à possibilidade de diferenciação de variedades de castanhas estes resultados preliminares parecem indicar a necessidade de análises complementares, que serão objecto de trabalho futuro.info:eu-repo/semantics/publishedVersio