Analysis of the colour profile of port wines using different instrumental methods and visual approaches

Colour is an important quality parameter in wines and is the result of a complex mixture of pigments (including anthocyanins and their derivatives, quinones, xanthyllium compounds, etc.). Red wine colour changes over time, as pigments react between themselves and with other wine macromolecules (particularly polyphenols). During wine tasting, colour is normally assessed on the outer rim of the wine in a tilted glass, since most wines are too opaque to be analysed in the middle of the glass. Therefore, depending on the depth of observation considered, the perception of wine colour can be different. The current official (OIV) method for measuring wine colour is based on UV/Vis spectrophotometric determination of the spectrum. In the current official (OIV) method, the transmittance spectrum of a particular sample is measured and used to calculate CIE-L*a*b* parameters (L*, a* and b*), which define a single (predominant) colour for a particular wine. Reflectance colorimetry is an alternative well-established method for measuring colour in foodstuffs, which can also be used in translucent samples (such as wines) as long as a reflective background is used. In this work, a reflectance colorimeter was used to measure CIE-L*a*b* colour parameters of Port wine samples of different categories at different depths, in Petri dishes. The obtained results were compared with the parameters obtained using the OIV method. In addition, the colour profile of Port wine samples was analysed using the colorimetric approach described above. An (untrained) panel was asked to assess the colour hue of the wine samples in Petri dishes, using an unstructured line scale, with the goal of establishing a correlation with the colorimetric readings at the same depths. The results suggest the colorimetric method can be used as an alternative to the OIV method for estimating the L* and H* parameters (the most important for wine colour definition), being quicker and more informative. In addition, there is a good correlation between H* parameter of colorimetric readings and the visual assessment of colour hue at all tested depths, being slightly better at lower depths. The colorimetric determination of wine colour at different depths can be conveniently used to characterize the visually perceived hue of Port wines.A cor é um parâmetro de qualidade importante em vinhos e é o resultado de uma mistura complexa de pigmentos (incluindo antocianinas e os seus derivados, quinonas, compostos xanthyllium, etc.). A cor do vinho muda ao longo do tempo, assim como os pigmentos reagem entre si e com outras macromoléculas presentes no vinho (especialmente polifenóis). Durante prova de vinhos, a cor é normalmente avaliada na orla do copo de vinho inclinado (45º), uma vez que a maioria dos vinhos são muito opacos para serem analisados no meio do copo. Por conseguinte, dependendo da profundidade de observação considerada, a perceção de cor de vinho pode ser diferente. O método oficial (OIV) para medir a cor de vinho é baseado na determinação espectrofotométrica UV / Vis. Neste método, o espectro de transmitância de uma determinada amostra é medida e usada para calcular os parâmetros CIE L * a * b *, que definem uma única cor (predominante) para um determinado vinho. Colorimetria pode ser considerado alternativo para a medição de cor em géneros alimentícios, também podendo ser utilizado em amostras translúcidas (tais como vinhos), desde que um fundo refletor seja usado. Neste trabalho, um colorímetro foi utilizado para medir parâmetros de cor CIEL* a*b* de amostras de vinho do Porto de categorias diferentes em diferentes profundidades, em placas de Petri. Os resultados obtidos foram comparados com os parâmetros obtidos usando o método OIV. Além disso, o perfil de cor de vinho do Porto amostras foi analisada utilizando a abordagem colorimétrica descrita acima. Além disto, um painel (não treinado) foi convidado a avaliar a tonalidade de cor das amostras de vinho em placas de Petri, usando uma escala linear não estruturada, com o objetivo de estabelecer uma correlação com as leituras colorimétricas com as mesmas profundidades. Os resultados sugerem que o método colorimétrico pode ser utilizado como uma alternativa ao método OIV para estimar os parâmetros L * e H * (importantes na definição da cor de vinho), sendo um método mais rápido e informativo. Além disso, boas correlações foram obtidas entre as medições com o colorímetro do parâmetro H* (CIE-L*a*b*) e a avaliação visual pelo painel da tonalidade da cor a todas as profundidades testadas, sendo ligeiramente melhor em profundidades inferiores. A determinação colorimétrica da cor do vinho a diferentes profundidades pode ser convenientemente utilizada para caracterizar a cor percebida visualmente em vinhos do Porto

Development of layered BNC composites for Food Packaging

The food industry is increasingly demanding advanced and sustainable packaging materials with improved physical, mechanical and barrier properties. The currently used materials are synthetic and non-degradable, which raises environmental concerns. Research efforts have been made in recent years towards the development of bio-based sustainable packaging materials. One of those is nanocellulose, which have a potential to be used as matrix, as nanofillers or as coatings for composites [1]. A promising material is bacterial nanocellulose (BNC), a biopolymer extruded by Komagaebacter xylinus as a 3D nanofibrillar network. BNC offers interesting properties such as high porosity, biocompatibility, non-toxicity and biodegradability [2]. From a food packaging perspective, BNC has a great potential due to the great mechanical performance. However, the high water affinity of BNC is ta major obstacle for food packaging applications [3]. Therefore, the first task was to develop a layered biodegradable composite based on a plasticized BNC (either with glycerol or polyethylene glycol) and poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), as an attempt to improve the water vapour permeability. The PHBV coating on plasticized BNC reduced significantly the water vapour permeability (from 0.990 to 0.032 g.m.m².day¹.Pa¹), increased the hydrophobicity (contact angle from 10-40° to 80-90°), but decreased the stiffness (from 3.1 GPa to 1.3 Gpa) of the BNC composite. The mechanical and barrier properties of the obtained layered composite were considered suitable for food packaging applications. Although the results obtained being important for food packaging, its commercial use is still far off due to production costs and low production capacity, especially when compared to plant-based nanocellulose [1]. Nevertheless, BNC is a proven material to support substances that play an active/intelligent role in food packaging, with ability to carry and release active substances [4, 5]. Therefore, a functionalized BNC film was developed, by in situ incorporating zinc oxide nanoparticles (ZnONPs). The synthesis of ZnONPs was based on co-precipitation method, using zinc acetate and sodium hydroxide (NaOH) (added dropwise) as reactants. In order to prevent aggregation of ZnO NPs, polyvinyl alcohol (PVOH) was used as capping agent. Overall, dropwise addition of NaOH in zinc acetate-PVOH (with immersed BNC), allowed the production of ZnONPs (144 nm), with low polydispersity index (0.139) and a homogeneous distribution of ZnONPs on the BNC. Concerning the antimicrobial activity, the minimum ZnO dosage for antimicrobial activity was 20%mZnO/mBNCZnO, being effective on gram bacteria (such Escherichia Coli) but only on some gram + bacteria (such Staphylococcus Aureus). The migration of ZnO onto food simulators are under testing.info:eu-repo/semantics/publishedVersio

Bacterial cellulose production through hydrolysates produced with cellulosic residues

In the paper industry, significant fraction of fibers that cannot be reutilized are wasted by the paper companies, which raise economic and environmental concerns. An increasing demand of bacterial cellulose (BC) has been noticed in the last years. In order to ally the recycling of lignocellulosic residues and the production of bacterial cellulose, Recycled paper sludge (RPS) and rejected fibers (EUR) were enzymatically hydrolyzed to obtain sugar hydrolysates, which were used for BC production. Exploratory assay (different strains and nitrogen sources) was performed with RPS and EUR hydrolysates. RPS hydrolysate showed to be an interesting an alternative carbon source for G. hansenii (5 g/L of BC) and EUR hydrolysate showed potential as carbon source for G. xylinum (4-5 g/L of BC). Overall, the results suggest that RPS and EUR residues have potential to be alternatives of carbon source for BC production, after a further optimization of the BC production and the enzymatic hydrolysis.The authors wish to thank Daniel Gomes for technical help. This work received financial support from FCT via project ID520405.ID1956.info:eu-repo/semantics/publishedVersio

Bacterial nanocellulose membrane as novel substrate for biomimetic structural color materials: Application to lysozyme sensing

The development of optical biosensors based on structural colors generated by short-range ordered colloidal particles is attracting growing interest due to their non-iridescent and non-fading features. In this study, a biomimetic approach using biopolymers for the various steps of sensor construction is presented. Bacterial nanocellulose (BNC) has many foreseen applications in biomedical engineering because of its biocompatibility, good mechanical strength, and large modifiable surface area. Herein, a novel approach is taken by using functionalized BNC as a substrate to build a molecularly imprinted photonic sensing layer. BNC was modified with polydopamine (PDA), which improved the adhesion and mechanical properties of the BNC substrate while providing simultaneously a black background for color saturation. A molecularly imprinted polymer (MIP) also made of PDA was used to create the recognition sites for the biomarker lysozyme. A monodisperse colloidal suspension of silica particles was first synthesized and used as core of the MIP shell, and then the photonic structure was assembled on the PDA-BNC membrane. The biosensor showed a detection limit of about 0.8nmolL1 of lysozyme in spiked human serum and demonstrated to be selective against cystatin C. These properties, combined with biocompatible, eco-friendly, and low-cost materials, offer a sustainable sensing platform with great potential for healthcare applications.info:eu-repo/semantics/publishedVersio

Bacterial cellulose production: valorization of wastewater and life cycle assessment

Low-cost substrates, most from agro-industrial wastes, have increasingly been exploited as nutrient sources for the fermentation of bacterial cellulose (BC), an appealing approach from an economical and environmental point of view. However, these wastes carry a very high organic load, which, while advantageous for the fermentation, generate high organic load wastewaters as well, which require proper treatment before the release or recycling of the treated water, which may have a significant impact in the economic and environmental sustainability of the BC production. Anaerobic digestion (AD), a process that produces biogas (primarily a mixture of methane and CO2) typically used for lighting and heating, is one of the most appropriate and promising treatments for high loaded industrial wastewaters. In this work, wastewaters from BC fermentation were characterized, as well as their biochemical methane potential and anaerobic biodegradability. The performance of an upflow anaerobic sludge blanket reactor (UASB) for the treatment of these wastewaters was also evaluated. Briefly, A relevant among of biogas could be produced from AD, while reducing the chemical oxygen demand (COD, an indirect measure the amount of organic compounds) of the treated waters [1]. The Life Cycle Assessment (LCA) is a methodology used to quantify the environmental, health and resource depletion impacts related to products, processes, and services. A LCA was used to a projected production of BC under static culture, including wastewater treatment, following a cradle-to-gate approach. From this study, a considerable amount of water is consumed, most of which being treated and emitted to the environment (to fresh water). The BC production facility itself had a small contribution to the consumption of resources and environmental impact of the global life cycle, most of which were associated with the production and transport of materials. Further, a comparative LCIA was made against plant celluloses. Briefly, with the increasing environmental awareness, BC production may be a strong candidate towards the reductions of environmental impacts and risks, concerning climate change and fossil resource depletion, while providing a viable, economically and environmentally sustainable bioproduct, with unique properties for a wide range of market applications [2].info:eu-repo/semantics/publishedVersio

A social and ecological assessment of tropical land uses at multiple scales: the Sustainable Amazon Network

Science has a critical role to play in guiding more sustainable development trajectories. Here, we present the Sustainable Amazon Network (Rede Amazonia Sustentavel, RAS): a multidisciplinary research initiative involving more than 30 partner organizations working to assess both social and ecological dimensions of land-use sustainability in eastern Brazilian Amazonia. The research approach adopted by RAS offers three advantages for addressing land-use sustainability problems: (i) the collection of synchronized and co-located ecological and socioeconomic data across broad gradients of past and present human use; (ii) a nested sampling design to aid comparison of ecological and socioeconomic conditions associated with different land uses across local, landscape and regional scales; and (iii) a strong engagement with a wide variety of actors and non-research institutions. Here, we elaborate on these key features, and identify the ways in which RAS can help in highlighting those problems in most urgent need of attention, and in guiding improvements in land-use sustainability in Amazonia and elsewhere in the tropics. We also discuss some of the practical lessons, limitations and realities faced during the development of the RAS initiative so far.Keywords: Social–ecological systems, Tropical forests, Land use, Interdisciplinary research, Sustainability, Trade-off

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| < 0.03 at 95% confidence level. [Figure not available: see fulltext.

Development and validation of HERWIG 7 tunes from CMS underlying-event measurements

This paper presents new sets of parameters (“tunes”) for the underlying-event model of the HERWIG7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG7, and are obtained from a fit to minimum-bias data collected by the CMS experiment at s=0.9, 7, and 13Te. The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the dat

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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