Changes in the volatile fraction composition of port wines during aging : a mechanistic approach

Os produtos alimentares durante o seu tempo de vida útil sofrem modificações químicas provocadas por conjuntos de reações reguladas por princípios termodinâmicos, sendo estas tradicionalmente agrupadas em diversos mecanismos. No processamento alimentar destaca-se a reação de Maillard que é dos mais descritos nos alimentos. O conhecimento da “mecânica” das reações e da sua possível interligação é fulcral para a compreensão e consequentemente para a monitorização da qualidade alimentar. Neste contexto, surge a motivação deste trabalho: elucidar sobre a possível interligação entre a reação de Maillard e a oxidação durante o envelhecimento do Vinho do Porto. De que forma estes mecanismos são afectados por parâmetros tecnológicos, como o oxigénio e a temperatura. E por fim saber de que forma podem ser controlados e assim providenciar formas de gerir o processo de envelhecimento e consequentemente a qualidade do produto. Foram usados vinhos envelhecidos durante 63 dias sob diferentes condições de oxigénio e temperatura e vinhos de diferentes idades que foram analisados por cromatografia gasosa acoplada a um detetor de ionização por chama e por espectrometria de massa. Compostos marcadores da reação de Maillard, oxidação e de um possível mecanismo que resulta da junção dos 2 que dá origem ao sotolon foram quantificados e calculados os respetivos parâmetros cinéticos, posteriormente usados para através de simulações de Monte Carlo prever a composição de vinhos armazenados em diferentes condições. Os perfis cromatográficos i.e. vetores de intensidade vs. tempos de retenção foram usados como impressões digitais químicos para encontrar mais marcadores relacionados com o processo. Foi criada uma nova técnica de visualização de cromatogramas que consiste na construção de uma rede com conexões (correlações de Pearson) entre tempos de retenção (compostos). Os parâmetros cinéticos demonstraram que a formação de sotolon é dependente do oxigénio e da temperatura, observando-se um efeito sinérgico entre ambos o que sustenta a hipótese da sua formação estar relacionada com o mecanismos de Maillard e a oxidação. As simulações demonstram que o efeito da temperatura tem maior impacto em vinhos armazenados em recipientes com elevada permeabilidade ao oxigénio (barris) do que naqueles com baixa permeabilidade (garrafas com rolha de cortiça). O uso dos perfis cromatográficos permite classificar as amostras de diferentes idades e encontrar mais marcadores relacionados com o processo. A reconstrução de redes é útil na priorização da identificação dos biomarcadores assim como permite uma visualização das cinéticas destes, compostos próximos têm a mesma expressão temporal e consequentemente obedecem á mesma ordem cinética e verificou-se que compostos agrupados são sensíveis aos mesmos parâmetros tecnológicos (oxigénio e temperatura). O controlo de parâmetros tecnológicos permite modular o perfil sensorial do vinho do Porto e consequentemente a sua qualidade. Este conhecimento tem elevado valor para a indústria porque permite gerir a qualidade e consequentemente aumentar o valor do produto.A food product during shelf life suffers chemical changes, caused by sets of reactions regulated by thermodynamics principles forming several mechanisms. In food processing, Maillard reaction is probably the most described. The knowledge of the different mechanism and their possible interconnections is central to understand and consequently monitor food quality. It is within this context, that the motivation of this thesis arose: to provide insights about the inter- connections between the Maillard reaction and oxidation during Port wine aging and how these mechanisms will be affected by technological parameters such as temperature and oxygen. Conclusively know how they can be controlled and thus provide ways to manage the aging process and consequently the quality of the product. In this context wines used were aged for 63 days under different conditions of temperature and oxygen and wines of different ages were analyzed by gas chromatography coupled to a flame ionization detector and to mass spectrometry. Marker compounds of Maillard reaction, oxidation and from a possible mechanism that outcomes from the previous ones which leads to sotolon were quantified and was calculated the respective kinetic parameters, these were used for through Monte Carlo simulations predict the composition of wine stored in different conditions of oxygen and temperature. The chromatographic profiles (vectors of intensity vs. retention times) were used as chemical fingerprints to find out more markers related with the process. A new approach for chromatographic data visualization was created consisting in a network of connections (Pearson correlations) between retention times (compounds). The kinetic parameters have shown that the formation of sotolon is highly dependent upon oxygen and temperature. Kinetics models with Monte Carlo simulations where applied and on the basis of the modeling predictions, it would seem that the temperature of a cellar would have a more significant impact on the Port wines stored in containers where the oxygen intake is higher (barrels) when compared to containers with low oxygen permeability (bottles with cork stoppers). The use of chromatographic profiles as samples fingerprints allows classifying samples of different ages and finding more markers related to the process. The network reconstruction provides considerably more information in an effort to understand the probable kinetic contexts of the molecules represented by peaks in each chromatogram. The technology developed in the study allows the modulation of the Port sensory profiles and consequently contributes to quality improvement. This knowledge has high value for the industry because it allows the management of the quality and therefore the increment of the product value

Chemiomics : a systematic chemistry approach to unravel the interface pathways between oxidation and Maillard mechanism responsible for flavour modulation during wine storage

Wine is a widely consumed beverage with a high commercial value, which price can increase with aging for a certain type. However, the knowledge of the chemical processes occurring during aging that result in a specific chemical/sensory profile remains limited. This lack of knowledge and understanding significantly limits the ability to improve product quality and consistency. For that reason, unravelling the chemical changes occurring during aging that are responsible for wine flavour, constitutes a critical task when one attempts to address issues related with authenticity and sensory quality. These considerable chemical modifications are related in particular with the formation of aroma active substances such as Strecker aldehydes. Depending on the storage conditions, namely related with dissolved oxygen, and availability, quality and quantity of antioxidants as well as precursors concentrations of key odorants the chemical profile of wines changes. In that regards these work presents several studies in order to evaluate the impact of such factors in the formation of Strecker aldehydes, in particular phenylacetaldehyde (Chapters 3, 4, 5 and 6) and other molecules (Chapter 7 and 8). In chapters 3, 4, 5 and 6, studies were performed in wine model solutions and the results demonstrated that the presence of metals, are relevant in promoting the Strecker degradation through phenolics oxidation pathways at wine pH. Also, this route is the major pathway for phenylacetaldehyde formation. For the first time it was demonstrated that the presence of glucose inhibits the formation of phenylacetaldehyde in both wine model systems and in white wine. By quinone quantitation it was shown that glucose affects directly their concentration, which suggest that in white wine glucose has an antioxidant effect by inhibiting o-quinones formation. In order to study the phenomenon in high complex systems, in chapters 7 and 8, aged white wines were studied.O vinho é uma bebida consumida mundialmente com alto valor comercial, cujo preço pode aumentar ou diminuir com o envelhecimento dependendo do tipo de vinho. No entanto, o conhecimento dos mecanismos químicos que ocorrem durante o processo que resultam em um perfil químico/sensorial específico permanece limitado. Essa falta de conhecimento limita significativamente a capacidade de melhorar a qualidade e consistência do produto. Por esse motivo, desvendar as alterações químicas que ocorrem durante o tempo de armazenamento, responsáveis pelas características do vinho, constitui uma tarefa crítica quando se tenta abordar questões relacionadas à autenticidade e qualidade sensorial. Estas consideráveis modificações químicas estão relacionadas, em particular, com a formação de substâncias ativas do aroma, como os aldeídos de Strecker Dependendo das condições de armazenamento, nomeadamente relacionadas com a concentração de oxigénio dissolvido, a disponibilidade, qualidade e quantidade de antioxidantes, e as concentrações de moléculas precursores de compostos odorantes, o perfil químico ao longo do armazenamento irá ser diferente. Nesse sentido, nesta tese vários estudos foram realizados para avaliar o impacto dos referidos fatores na formação dos aldeídos de Strecker, em particular o fenilacetaldeído (capítulos 3, 4, 5 e 6) e outras moléculas (capítulos 7 e 8). Os estudos realizados basearam-se numa abordagem holística de forma a avaliar vários fatores ao mesmo tempo assim como a interação entre eles. Nos capítulos 3, 4, 5 e 6, foram realizados estudos em soluções modelo de vinho e os resultados demonstraram que a presença de metais é relevante na promoção da degradação de Strecker por vias de oxidação de fenólicos no pH do vinho. Além disso, esta rota é a principal via para a formação de fenilacetaldeído. Pela primeira vez, foi demonstrado que a presença de glicose inibe a formação de fenilacetaldeído nos sistemas modelo de vinho e no vinho branco. Pela quantificação da quinona, foi demonstrado que a glicose afeta diretamente sua concentração, o que sugere que no vinho branco a glicose tem um efeito antioxidante ao inibir a formação de o-quinonas. Para estudar o fenômeno em sistemas de alta complexidade, nos capítulos 7 e 8, foram estudados vinhos brancos sujeitos a envelhecimento por diversos períodos de tempo e submetidos a tratamento por aplicação de resinas catiónicas

Chemiomics: network reconstruction and kinetics of Port Wine aging

Network reconstruction (NR) has proven to be useful in the detection and visualization of relationships among the compounds present in a Port wine aging data set. This view of the data provides a considerable amount of information with which to understand the kinetic contexts of the molecules represented by peaks in each chromatogram. The aim of this study was to use NR together with the determination of kinetic parameters to extract more information about the mechanisms involved in Port wine aging. The volatile compounds present in samples of Port wines spanning 128 years in age were measured with the use of GC-MS. After chromatogram alignment, a peak matrix was created, and all peak vectors were compared to one another to determine their Pearson correlations over time. A correlation network was created and filtered on the basis of the resulting correlation values. Some nodes in the network were further studied in experiments on Port wines stored under different conditions of oxygen and temperature in order to determine their kinetic parameters. The resulting network can be divided into three main branches. The first branch is related to compounds that do not directly correlate to age, the second branch contains compounds affected by temperature, and the third branch contains compounds associated with oxygen. Compounds clustered in the same branch of the network have similar expression patterns over time as well as the same kinetic order, thus are likely to be dependent on the same technological parameters. Network construction and visualization provides more information with which to understand the probable kinetic contexts of the molecules represented by peaks in each chromatogram. The approach described here is a powerful tool for the study of mechanisms and kinetics in complex systems and should aid in the understanding and monitoring of wine quality.info:eu-repo/semantics/acceptedVersio

In vitro gastrointestinal digestion impact on the bioaccessibility and antioxidant capacity of bioactive compounds from tomato flours obtained after conventional and ohmic heating extraction

In times of pandemic and when sustainability is in vogue, the use of byproducts, such as fiber-rich tomato byproducts, can be an asset. There are still no studies on the impact of extraction methodologies and the gastrointestinal tract action on bioactive properties. Thus, this study used a solid fraction obtained after the conventional method (SFCONV) and a solid fraction after the ohmic method (SFOH) to analyze the effect of the gastrointestinal tract on bioactive compounds (BC) and bioactivities. Results showed that the SFOH presents higher total fiber than SFCONV samples, 62.47 ± 1.2459.06 ± 0.67 g/100 g DW, respectively. Both flours present high amounts of resistant protein, representing between 11 and 16% of insoluble dietary fiber. Furthermore, concerning the total and bound phenolic compounds, the related antioxidant activity measured by 2,2-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical cation decolorization assay presented significantly higher values for SFCONV than SFOH samples (p < 0.05). The main phenolic compounds identified in the two flours were gallic acid, rutin, and p-coumaric acid, and carotenoids were lycopene, phytofluene, and lutein, all known as health promoters. Despite the higher initial values of SFCONV polyphenols and carotenoids, these BCs OH flours were more bioaccessible and presented more antioxidant capacity than SFCONV flours, throughout the simulated gastrointestinal tract. These results confirm the potential of ohmic heating to modify the bioaccessibility of tomato BC, enhancing their concentrations and improving their antioxidant capacity.The authors would like to thank to “MultiBiorefinery: Estratégias multiuso para a valorização de uma gama alargada de subprodutos agroflorestais e das pescas: Um passo em frente na criação de uma biorrefinaria” financiado pelo Programa Operacional Competitividade e Internacionalização (POCI-01-0145-FEDER-016403) e pelo Programa Operacional Regional de Lisboa(LISBOA-01-0145-FEDER-016403), na sua componente FEDER e pela Fundação para a Ciência e Tecnologia, I.P. na componente nacional (SAICTPAC/0040/2015). The authors would also like to thank the scientific collaboration under the FCT project UID/Multi/50016/2019, UID-BIM-00009- 2020, and UID/BIO/04469/2020. The author Marta Coelho would like to acknowledge FCT for your grant with the reference (grant number SFRH/BD/111884/2015).info:eu-repo/semantics/publishedVersio

Prebiotic effects of olive pomace powders in the gut: In vitro evaluation of the inhibition of adhesion of pathogens, prebiotic and antioxidant effects

Supplementary data related to this article can be found at https:// doi.org/10.1016/j.foodhyd.2020.106312Olive pomace is a biowaste rich in polyphenols and insoluble dietary fibre with high potential to develop new value chains towards a sustainable and circular bioeconomy. Regarding gut health, olive pomace phenolics and insoluble dietary fibre (after possible fermentation) could act as antioxidants, antimicrobial and prebiotic agents. These potential beneficial effects on the gut were analysed for two powders from olive pomace: liquid-enriched powder (LOPP) - mostly source of phenolics - and pulp-enriched powder (POPP) - main source of insoluble dietary fibre. LOPP and POPP were subjected to an in vitro simulated gastrointestinal digestion followed by in vitro faecal fermentation. The undigested fraction retained in the colon was analysed regarding its potential antioxidant, antimicrobial and prebiotic effects. LOPP and POPP did not impact the gut microbiota diversity negatively, showing a similar ratio of Firmicutes/Bacteroidetes compared to a positive control (FOS). LOPP exhibit a positive (similar to FOS) effect on the Prevotella spp./Bacteroides spp. ratio. Both powders also promoted more the production of short-chain fatty acids (mainly acetate?>?butyrate?>?propionate) than FOS. Both powders showed also significant total phenolic content and oxygen radical absorbance capacity during faecal fermentation until 48?h. Besides that, these powders showed mucin-adhesion inhibition ability against pathogens, principally POPP against Bacillus cereus (22.03?±?2.45%) and Listeria monocytogenes (20.01?±?1.93%). This study demonstrates that olive pomace powders have prebiotic effects on microbiota, including the stimulation of short-chain fatty acids production, potential antioxidant and antimicrobial activity which could improve human gut health.Tˆania I. B. Ribeiro thanks the FCT - Fundação para a Ciência e Tecnologia, Portugal and Association BLC3 – Technology and Innovation Campus, Centre Bio R&D Unit for the PhD Grant SFRH/BDE/108271/2015. This work was supported by National Funds from FCT - Fundação para a Ciência e a Tecnologia, Portugal through the project MULTI-BIOREFINERY - SAICTPAC/0040/2015 (POCI-01-0145-FEDER- 016403). We would also like to thank the scientific collaboration under the FCT project UID/Multi/50016/2019.info:eu-repo/semantics/publishedVersio

Genetic mechanisms of critical illness in COVID-19.

Host-mediated lung inflammation is present1, and drives mortality2, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development3. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079, P = 1.65 × 10-8) in a gene cluster that encodes antiviral restriction enzyme activators (OAS1, OAS2 and OAS3); on chromosome 19p13.2 (rs74956615, P = 2.3 × 10-8) near the gene that encodes tyrosine kinase 2 (TYK2); on chromosome 19p13.3 (rs2109069, P = 3.98 ×  10-12) within the gene that encodes dipeptidyl peptidase 9 (DPP9); and on chromosome 21q22.1 (rs2236757, P = 4.99 × 10-8) in the interferon receptor gene IFNAR2. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of IFNAR2, or high expression of TYK2, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte-macrophage chemotactic receptor CCR2 is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice

Port wine oxidation management: a multiparametric kinetic approach

Port wine is a flagship fortified wine of Portugal, which undergoes a particularly long aging period, developing a dynamic sensory profile over time, responsible for several wine categories, which is dependent upon the type of aging (bottle or barrel). Therefore, the quality of the product is dependent upon the chemical mechanisms occurring during the aging process, such as oxidation or Maillard reactions. To attain the desired quality management, it is necessary to understand how technological parameters, such as temperature or oxygen exposure, affect the kinetics of the formation of key odorants, such as sotolon. There is a lack of information about the impact of the storage conditions (oxygen and temperature) on Port wine quality. In this study, the effect of these two parameters were investigated to increase the knowledge database concerning aging management of Port wines. It was found that sotolon formation is highly dependent upon oxygen and temperature. There is however a synergistic effect between these two parameters that could significantly increase the concentration. The kinetic parameters of oxygen, sotolon, and other compounds related to Port aging (cis- and trans-5-hydroxy-2-methyl-1,3-dioxan, 2-furfural, 5-hydroxy-methyl-furfural, and 5-methyl-furfural) are also reported. Kinetic models with Monte Carlo simulations, where the oxygen permeability dispersion and temperature are the parameters under evaluation, were applied. On the basis of the modeling predictions, it would seem that the temperature of a cellar would have a more significant impact on the Port wines stored in containers where the oxygen intake is higher (barrels) when compared to containers with low oxygen permeability (bottles using cork stoppers).This research was funded by Project "Wine Metrics: Revealing the Volatile Molecular Feature Responsible for the Wine-Like Aroma A Critical Task toward the Wine Quality Definition" (PTDC/AGR-ALI/121062/2010), partially supported by ESB/UCP plurianual funds through the POS-Conhecimento Program that includes FEDER funds through the program COMPETE (Programa Operacional Factores de Competitividade) by Portuguese national funds through Fundacao para a Ciencia e a Tecnologia (FCT). Thanks are due to Corksupply Portugal, S.A. for oxygen measurement support and Symington Co., Porto for kindly donated the Port Wine

Untangling the chemistry of Port wine aging with the use of GC-FID, multivariate statistics, and network reconstruction

Chromatography separates the different components of complex mixtures and generates a fingerprint representing the chemical composition of the sample. The resulting data structure depends on the characteristics of the detector used, univariate for devices such as a flame ionization detector (FID) or multivariate for mass spectroscopy (MS). This study addresses the potential use of a univariate signal for a nontargeted approach to (i) classify samples according to a given process or perturbation, (ii) evaluate the feasibility of developing a screening procedure to select candidates related to the process, and (iii) provide insight into the chemical mechanisms that are affected by the perturbation. To achieve this, it was necessary to use and develop methods for data preprocessing and visualization tools to assist an analytical chemist to view and interpret complex multidimensional data sets. Dichloromethane Port wine extracts were collected using GC-FID; the chromatograms were then aligned with correlation optimized warping (COW) and subsequently analyzed with multivariate statistics (MVA) by principal component analysis (PCA) and partial least-squares regression (PLS-R). Furthermore, wavelets were used for peak calling and alignment refinement, and the resulting matrix was used to perform kinetic network reconstruction via correlation networks and maximum spanning trees. Network-target correlation projections were used to screen for potential chromatographic regions/peaks related to aging mechanisms. Results from PLS between aligned chromatograms and target molecules showed high X to Y correlations of 0.91, 092, and 0.89 with 5-hydroxymethylfurfural (HMF) (Maillard), acetaldehyde (oxidation), and 4,5-dimethyl-(5H)-3-hydroxy-2-furanone, respectively. The context of the correlation (and therefore likely kinetic) relationships among compounds detected by GC-FID and the relationships between target compounds within different regions of the network can be clearly seen.info:eu-repo/semantics/publishedVersio