3,629 research outputs found
A few cosmological implications of tensor nonlocalities
We consider nonlocal gravity theories that include tensor nonlocalities. We
show that in the cosmological context, the tensor nonlocalities, unlike scalar
ones, generically give rise to growing modes. An explicit example with
quadratic curvature terms is studied in detail. Possible consequences for
recent nonlocal cosmological models proposed in the literature are also
discussed.Comment: 7 pages. New references include
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
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
Efeito da radiação gama nos níveis de tocoferóis em Lactarius deliciosus
Os efeitos da radiação gama no teor de tocoferóis em Lactarius deliciosus L. Gray foi avaliado em amostras submetidas a diferentes períodos de armazenamento a 4 ºC. As doses aplicadas foram 0,5 e 1 kGy a um débito de dose de 2,3 kGy/h, usando uma câmara de radiação gama com fonte de 60Co. Após tratamento, as amostras foram armazenadas sob refrigeração (4 a 5 ºC) e analisadas aos 0, 4 e 8 dias de armazenamento. A composição em tocoferóis foi determinada por HPLC-fluorescência.
As amostras não sujeitas a radiação e analisadas de imediato foram os únicos casos em que se detetou β-tocoferol (93±11 μg/100 g massa seca) e γ-tocoferol (68±6 μg/100 g massa seca); sendo que as restantes isoformas diminuíram nas amostras irradiadas e armazenadas, presumivelmente devido a processos oxidativos.
Os dados obtidos mostram que, até 1 kGy, a irradiação gama pode fornecer uma alternativa conveniente para garantir a qualidade e prolongar a vida útil de cogumelos.FCT e COMPETE/QREN/UE- projetos estratégicos PEst-OE/AGR/UI0690/2011 do CIMO e PEst-C/EQB/LA0006/2011 do REQUIMTE; bolsa SFRH/BD/76019/2011 concedida a A. Fernande
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
Effects of gamma radiation on physical and chemical parameters of wild Lactarius deliciosus L.
The short shelf life of mushrooms is a barrier to their distribution and, therefore, there
has been extensive research to find technologies that ensure the preservation of
mushrooms, maintaining their organoleptic properties. Irradiation is an alternative that
has already been successfully applied in various food products1. There are several
studies in the literature assessing the effects of the application of ionizing radiation in
cultivated mushrooms in particular Agaricus bisporus, Lentinus edodes and Pleurotus
ostreatus, as reviewed recently by our research group.2 However, there are almost no
studies on wild species, which are generally highly valued commercially. Herein, the
effects of gamma radiation on physical and chemical properties of wild Lactarius
deliciosus L. were evaluated. Irradiation was performed in an experimental equipment
with 60Co sources (at the doses 0.5 and 1 kGy) and analyzes were performed throughout
the period of storage at 4 °C (0, 4 and 8 days). All results were compared with nonirradiated
samples (control). The physical properties determined were mass, color and
diameter of the cap3; the chemical properties evaluated included nutritional profile, and
fatty acids, tocopherols, mono and oligosaccharides by chromatographic techniques4.
The irradiated samples showed similar properties to the control. Up to 1 kGy, gamma
irradiation may be an alternative to ensure the quality and prolong the shelf life of
mushrooms, since the effects on the tested parameters were less significant than that
caused by the storage time.FCT and COMPETE/QREN/UE- strategic projects PEst-OE/AGR/UI0690/2011
(CIMO) and PEst-C/EQB/LA0006/2011 (REQUIMTE); grant SFRH/BD/76019/2011 to
A. Fernandes
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