Efeito da temperatura no comportamento reológico de méis colhidos na região nordeste de Portugal

No presente trabalho pretendeu-se estudar o efeito da temperatura sobre as propriedades reológicas de três méis colhidos no nordeste de Portugal. Para isso, analisaram-se dois méis monoflorais - urze e rosmaninho - provenientes do Parque Natural de Montesinho, e um mel polifloral, recolhido na Freguesia de Morais, local de interesse geológico. O comportamento reológico destes méis foi avaliado às temperaturas de 30, 50, 70 e 95 °C. Todos os méis estudados apresentaram um fluxo independente do tempo e a sua maioria comportou-se como um Fluido Newtoniano. Apenas o mel de urze à temperatura de 50 °C e o mel de rosmaninho à temperatura de 95 °C demonstraram ter comportamento de Fluido Pseudoplástico. De entre os méis analisados, o mel de rosmaninho foi aquele que mostrou ser mais sensível à temperatura, apresentando o valor mais elevado de energia de activação (81 ,3 kJ/mol). No que respeita à consistência, o mel pode apresentar-se fluido, espesso ou, parcial ou totalmente cristalizado. Como o mercado, em grande parte, favorece a venda do mel líquido, alguns tipos de tratamento são necessários para manter o mel nesse estado, tais como, a filtração e o aquecimento. O aquecimento é aplicado por inúmeras razões, como por exemplo, para facilitar a sua manipulação e acondicionamento, retardar o fenómeno de granulação e destruir microrganismos que possam estar presentes e que possam alterar negativamente a qualidade do mel. No presente trabalho estudou-se as propriedades reológicas de três méis colhidos no nordeste de Portugal. Dois méis monoflorais – urze e rosmaninho – provenientes do Parque Natural de Montesinho, e um mel polifloral do Sítio de Morais. Como o aquecimento é aplicado para manter o mel em estado líquido e como também é utilizado na preparação de vários pratos culinários, o comportamento reológico desses méis foi analisado às temperaturas de 30, 50, 70 e 95 ºC. Para tal, foi utilizado um viscosímetro de cilindros concêntricos equipado com um controlador de temperatura. Todos os méis estudados apresentaram um fluxo independente do tempo e a sua maioria comportou-se como um Fluido Newtoniano, ou seja, com viscosidade constante. Apenas o mel de urze à temperatura de 50 °C e o mel de rosmaninho à temperatura de 95 °C demonstraram ter comportamento de um Fluido Pseudoplástico. A dependência da viscosidade com a temperatura foi descrita pela equação de Arrhenius, tendo a energia de activação (Ea) variado entre 72,6 e 81,3 KJ/mol. De entre os méis analisados, o mel de rosmaninho foi aquele que mostrou ser mais sensível à temperatura, apresentando o valor mais elevado de Ea (81,3 kJ/mol)

Temperature Effect on Rheological Behavior of Portuguese Honeys

In the present work the temperature effect on rheological properties of Portuguese honeys was studied for the fi rst time. Two unifl oral honeys – heather and rosemary – and a polyfl ower honey were analyzed. All honeys showed fl ow independence over time and behaved as Newtonian fl uids at the studied temperature and shear rate ranges. For all honeys it was found that the viscosity decreased with temperature and the rosemary honey was the one that always presented the lowest viscosity at 30°C (6120 mPa·s), 50°C (603 mPa·s) and 70°C (145 mPa·s). The temperature dependence of viscosity was well described by the T B A K e 0 equation. Nevertheless, good regression coeffi cients were also obtained when fi tting the experimental data to the Arrhenius model, showing the rosemary honey to be less temperature sensitive. The results obtained in this study are of great interest to beekeepers and industrials that handle and prepare eatable honey-based products because they will be better informed about the best type of honey to use.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for fi nancial support to CIMO (UID/ AGR/00690/2013).info:eu-repo/semantics/publishedVersio

Electrochemical study of butylate: application to the analysis of water

The electroactivity of butylate (BTL) is studied by cyclic voltammetry (CV) and square wave voltammetry (SWV) at a glassy carbon electrode (GCE) and a hanging mercury drop electrode (HMDE). Britton–Robinson buffer solutions of pH 1.9–11.5 are used as supporting electrolyte. CV voltammograms using GCE show a single anodic peak regarding the oxidation of BTL at +1.7V versus AgCl/ Ag, an irreversible process controlled by diffusion. Using a HMDE, a single cathodic peak is observed, at 1.0V versus AgCl/Ag. The reduction of BTL is irreversible and controlled by adsorption. Mechanism proposals are presented for these redox transformations. Optimisation is carried out univaryingly. Linearity ranges were 0.10–0.50 mmol L-1 and 2.0–9.0 µmolL-1 for anodic and cathodic peaks, respectively. The proposed method is applied to the determination of BTL in waters. Analytical results compare well with those obtained by an HPLC method

Commercial octopus species from different geographical origins: Levels of polycyclic aromatic hydrocarbons and potential health risks for consumers

Polycyclic aromatic hydrocarbons (PAHs) are persistent pollutants that have been raising global concern due to their carcinogenic and mutagenic properties. A total of 18 PAHs (16 USEPA priority compounds, benzo(j)fluoranthene and dibenzo(a,l)pyrene) were assessed in the edible tissues of raw octopus (Octopus vulgaris, Octopus maya, and Eledone cirrhosa) from six geographical origins available to Portuguese consumers. Inter- and intra-species comparison was statistically performed. The concentrations of total PAHs (∑PAHs) ranged between 8.59 and 12.8 μg/kg w.w. Octopus vulgaris caught in northwest Atlantic Ocean presented ΣPAHs significantly higher than those captured in Pacific Ocean and Mediterranean Sea, as well as than the other characterized species from western central and northeast Atlantic Ocean. PAHs with 2-3 rings were the predominant compounds (86-92% of ∑PAHs) but diagnostic ratios indicated the existence of pyrogenic sources in addition to petrogenic sources. Known and possible/probable carcinogenic compounds represented 11-21% of ΣPAHs. World and Portuguese per capita ingestion of ∑PAHs due to cephalopods consumption varied between 1.62-2.55 × 10-4 and 7.09-11.2 × 10-4 μg/kg body weight per day, respectively. Potential risks estimated for low and high consumers according to USEPA methodology suggested that a regular consumption of raw octopus does not pose public health risks.This work was supported by European Union (FEDER funds through COMPETE) and National Funds (Fundação para a Ciência e Tecnologia) through projects UID/QUI/50006/2013 and POCI-01-0145-FEDER-007265, by the FCT/MEC with national funds and co-funded by FEDER in the scope of the P2020 Partnership Agreement. Additional financial support was provided by Fundação para a Ciência e a Tecnologia through fellowships SFRH/BD/52502/2014 (Filipa Gomes) and PD/BD/109660/2015 (Álvaro Torrinha).info:eu-repo/semantics/publishedVersio

Effect of stirring and ultrasound assisted extraction conditions in flavonoids, tannins, antioxidant and antimicrobial activities of chestnut outer shells (Castanea sativa Miller)

Portugal is one of the main producersof chestnut in Europe.info:eu-repo/semantics/publishedVersio

Potential of Portuguese vine shoot wastes as natural resources of bioactive compounds

Since annually a high amount of wastes is produced in vine pruning, the aim of this study was to evaluate the potential of vine shoots from two Portuguese grape varieties (Touriga Nacional - TN and Tinta Roriz - TR) to be used as a natural source of phenolic compounds. To reach this goal, three techniques were explored, namely microwave-assisted extraction (MAE), subcritical water extraction (SWE) and conventional extraction (CE). The phenolic composition of the extracts, antioxidant and biological activities were evaluated by spectrophotometry and chromatography. MAE and SWE produced the highest concentrated extracts. TR vine shoot variety had the highest antioxidant activity and total phenolic (32.1±0.9mggallicacidequivalents/g dry sample), as well as flavonoid content (18.7±1.2mgepicatechinequivalents/g dry sample). For the first time, the biological activity of the vine shoot extracts was tested. Results demonstrated that all of them had antimicrobial potential against different bacteria and yeasts, and the ability of inhibiting α-amylase and acetylcholinesterase enzymes, with MAE TR extracts being the most efficient. HPLC analysis enabled the identification of different phenolic compounds, with gallic acid, catechin, myricetin and kaempferol-3-O-rutinoside being the main contributors to the phenolic composition. Portuguese vine shoot wastes could serve as easily accessible source of natural antioxidants for the food or pharmaceutical industries.Manuela M. Moreira (SFRH/BPD/97049/2013) and M. F. Barroso (SFRH/BPD/78845/2011) are grateful for the postdoctoral fellowships financed by POPH-QREN – Tipologia 4.1 – Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência, Tecnologia e Ensino Superior. The authors are also grateful for the financial support from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020 through the project UID/QUI/50006/2013 - POCI/01/0145/FEDER/007265; the project 6818 - Transnational Cooperation, Agreement between Portugal (FCT) and Serbia (MSTD) is also acknowledged. This work was also supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI). The supply of the vine shoots is acknowledged to Sogrape Vinhos, S.A.info:eu-repo/semantics/publishedVersio

Plant and soil metal concentrations in serpentine soils and their influence on the diet of extensive livestock animals

Background: Grazing circuits and resources consumed differ strongly throughout the year and within a territory. For this reason, animals’ diet composition, as well as their exposure to metals, is variable. No studies have been performed on how habitat use affects the metal concentrations to which sheep and goats reared in serpentine soil areas are exposed. Objective: The aim of the present study was to investigate the metal exposure of grazing animals raised in a serpentine soil area of the north-east of Portugal, taking into account the spatial distribution of metal concentrations in soils and plants. Methods: The habitat use and foraging behaviour of six flocks of sheep and goats were studied. The concentrations of Ca, Mg, Mn, Cr and Ni were determined in the soils and plant species most consumed by those animals. Results: The highest Mg, Mn, Cr and Ni concentrations were found in the soils of the ultramafic complex. Ni concentrations above the recommended threshold for agricultural soils (30 μg/g) were found in some sites. A positive correlation between Ni concentration in soils and plants was found (0.634). Ni concentrations higher than 10 μg/g were found in some samples of the following plant species: Sorghum × drummondii (Steud.) Millsp. & Chase,Quercus rotundifolia Lam., Cytisus multiflorus (L’Hér.) Sweet, Cistus ladanifer L. and Erica scoparia L. Significant differences (p ≤ 0.05) in metal concentrations of the plants most consumed by each flock were observed. Conclusion: Grazing circuits have an important role in the metal exposure of animals raised in this serpentine soil area.info:eu-repo/semantics/publishedVersio

Honey as an Adjuvant in the Treatment of COVID-19 Infection: A Review

Since ancestor times, honey has been used to promote human health due to its medicinal, and nutritious properties, mainly due to bioactive compounds present, such as phenolic compounds. The emergence of COVID-19, caused by the SARS-CoV-2 virus, led to the pursuit of solutions for the treatment of symptoms and/or disease. Honey has proven to be effective against viral infections, principally due to its potential antioxidant and anti-inflammatory activities that attenuate oxidative damage induced by pathogens, and by improving the immune system. Therefore, the aim of this review is to overview the abilities of honey to attenuate different COVID-19 symptoms, highlighting the mechanisms associated with these actions and relating the with the different bioactive compounds present. A brief, detailed approach to SARS-CoV-2 mechanism of action is first overviewed to allow readers a deep understanding. Additionally, the compounds and beneficial properties of honey, and its previously application in other similar diseases, are detailed in depth. Despite the already reported efficacy of honey against different viruses and their complications, further studies are urgently needed to explain the molecular mechanisms of activity against COVID-19 and, most importantly, clinical trials enrolling COVID-19 patients.This research was funded by MTS/SAS/0077/2020—Honey+—New reasons to care honey from the Natural Park of Montesinho: A bioindicator of environmental quality & its therapeutic potential, and by the projects UIDB/50006/2020, UIDP/50006/2020, and LA/P/0008/2020, all supported by Fundação para a Ciência e a Tecnologia (FCT)/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES). We are thankful to the Fundação para a Ciência e a Tecnologia (Portugal) through project MTS/SAS/0077/2020—Honey+—New reasons to care honey from the Natural Park of Montesinho: A bioindicator of environmental quality & its therapeutic potential. This work was also financially supported by Portuguese national funds through projects UIDB/50006/2020, UIDP/50006/2020, UIDB/04033/2020 and LA/P/0008/2020, from the Fundação para a Ciência e a Tecnologia (FCT)/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES). Francisca Rodrigues and Clara Grosso are thankful for their contracts (CEECIND/01886/2020 and CEECIND/03436/2020) financed by FCT/MCTES—CEEC Individual 2020 Program Contract. Juliana Garcia is grateful to FCT and BPI La Caixa Foundation, within the project titled ‘AquaeVitae—Água Termal Como Fonte de Vida e Saúde”—“PROMOVE—O futuro do Interior” call 2020 and “AquaValor—Centro de Valorização e Transferência de Tecnologia da Água” (NORTE-01-0246-FEDER-000053), supported by Norte Portugal Regional Operational Programme (NORTE 2020) under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio

Analysis of polycyclic aromatic hydrocarbons in fish: optimisation and validation of microwave-assisted extraction

An accurate and sensitive method for determination of 18 polycyclic aromatic hydrocarbons (PAHs) (16 PAHs considered by USEPA as priority pollutants, dibenzo[a,l]pyrene and benzo[j]fluoranthene) in fish samples was validated. Analysis was performed by microwave-assisted extraction and liquid chromatography with photodiode array and fluorescence detection. Response surface methodology was used to find the optimal extraction parameters. Validation of the overall methodology was performed by spiking assays at four levels and using SRM 2977. Quantification limits ranging from 0.15–27.16 ng/g wet weight were obtained. The established method was applied in edible tissues of three commonly consumed and commercially valuable fish species (sardine, chub mackerel and horse mackerel) originated from Atlantic Ocean. Variable levels of naphthalene (1.03–2.95 ng/g wet weight), fluorene (0.34–1.09 ng/g wet weight) and phenanthrene (0.34–3.54 ng/g wet weight) were detected in the analysed samples. None of the samples contained detectable amounts of benzo[a]pyrene, the marker used for evaluating the occurrence and carcinogenic effects of PAHs in food

Analysis of polycyclic aromatic hydrocarbons in fish: evaluation of a quick, easy, cheap, effective, rugged, and safe extraction method

QuEChERS method was evaluated for extraction of 16 PAHs from fish samples. For a selective measurement of the compounds, extracts were analysed by LC with fluorescence detection. The overall analytical procedure was validated by systematic recovery experiments at three levels and by using the standard reference material SRM 2977 (mussel tissue). The targeted contaminants, except naphthalene and acenaphthene, were successfully extracted from SRM 2977 with recoveries ranging from 63.5–110.0% with variation coefficients not exceeding 8%. The optimum QuEChERS conditions were the following: 5 g of homogenised fish sample, 10 mL of ACN, agitation performed by vortex during 3 min. Quantification limits ranging from 0.12– 1.90 ng/g wet weight (0.30–4.70 µg/L) were obtained. The optimized methodology was applied to assess the safety concerning PAHs contents of horse mackerel (Trachurus trachurus), chub mackerel (Scomber japonicus), sardine (Sardina pilchardus) and farmed seabass (Dicentrarchus labrax). Although benzo(a)pyrene, the marker used for evaluating the carcinogenic risk of PAHs in food, was not detected in the analysed samples (89 individuals corresponding to 27 homogenized samples), the overall mean concentration ranged from 2.52 l 1.20 ng/g in horse mackerel to 14.6 ± 2.8 ng/ g in farmed seabass. Significant differences were found between the mean PAHs concentrations of the four groups