The diverse effects of yeast on the aroma of non-sulfite added white wines throughout aging

Semi-synthetic must containing standard nutrients, a phenolic and aromatic fraction extracted from Albariño grapes and synthetic precursors of 3-mercaptohexanol (MOH) and 4-mercapto-4-pentan-2-one (MMP) were fermented with three different selected commercial S. cerevisiae yeasts. Wines were subjected to anoxic aging at 50 °C for 1, 2, 5 and 8 weeks, and their volatile composition was comprehensively determined by the analysis of 86 different aroma compounds using five different GC methods. Yeasts exert a strong influence on wine aroma throughout the whole aging period. Their effects extend beyond the well-known actions on yeast secondary metabolites, including the formation of little amounts of Strecker aldehydes or the formation of acids precursors of fruity esters, and on the enzymatic actions on the different grape aroma precursors. Additionally, yeasts influence wine aroma; first, by producing SO2 which reacts with ß-damascenone and increases Strecker aldehyde production in fermentation; second, by inducing the differential accumulation of Strecker aldehydes during anoxic aging; and third, by determining the stability of MOH, likely because of its reaction with vinylphenols or other yeast-related electrophiles

Accurate quantitative determination of the total amounts of Strecker aldehydes contained in wine. Assessment of their presence in table wines

Strecker aldehydes (SAs) are key determinants of wine shelf-life and can be present in unoxidized wines in odorless forms, such as hydroxyalkylsulfonates, imines or acetals. A robust and accurate method for the determination of total forms of SAs, based on the classical derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and in the selective solid phase extraction of derivatives has been optimized and validated. Matrix effects have been solved by the use of adequate internal standards and by large-enough equilibration times under anoxic conditions. Method figures of merit are highly satisfactory in terms of detection limits ( 0.997), reproducibility (5–13%) and recoveries (RSDs, between 2 and 10%, for 3-methylbutanal, 14%). The analysis of total SAs in 108 Spanish wines revealed that between 52% and 70% of unoxidized red wines and likely a similar fraction of white wines, contain levels of SAs high enough to cause oxidative aromas if bound forms of SAs cleave

Determinación de compuestos volátiles liberados durante el proceso de fritura usando aceite de oliva y girasol. Evaluación sensorial de los compuestos identificados

Entre los medios de cocinado más habituales se encuentra la fritura, en la que se utilizan aceites y grasas a elevadas temperaturas. Este proceso puede conllevar diferentes problemas como son la combustión del aceite, la toxicidad de los productos generados durante el calentamiento y la generación de propiedades organolépticas adversas. Para poder controlar estos problemas se llevó a cabo un estudio sobre la composición de los humos generados. Para ello, se desarrollaron dos métodos diferentes basados en extracción en fase sólida (SPE) y en microextracción en fase sólida (SPME) con agente derivatizante, ambas con posterior análisis en un cromatógrafo de gases con espectrometría de masas (CG-MS). Además, se realizó un estudio sobre la contribución de los compuestos identificados al olor característico de un proceso de fritura. En los extractos obtenidos mediante SPE se identificaron 23 compuestos diferentes (todos ellos ácidos, alcanos o aldehídos), realizando los ANOVAS correspondientes para conocer la influencia del tipo de aceite y la temperatura de fritura en la composición de los humos. Los compuestos que aparecieron en mayor cantidad fueron los aldehídos. Se observó como un mayor porcentaje de ácido oleico, linoleico y linolénico en los aceites correspondía a una mayor cantidad de los aldehídos generados como consecuencia de la descomposición del correspondiente ácido graso. En el experimento realizado con SPME se determinó la acroleína en los dos tipos de aceite a tres temperaturas diferentes. En el estudio sensorial quedó reflejada la importancia de los aldehídos insaturados en el olor de los procesos de fritura, habiendo observado un efecto sinérgico muy significativo en este grupo de compuesto

The significance of cheese sampling in the determination of histamine concentration: Distribution pattern of histamine in ripened cheeses

Cheeses are becoming a major safety and public health concern: cheeses available in supermarkets occasionally contain high histamine concentrations that can have negative effects on consumer health. In this study, we have attempted to assess the histamine distribution pattern in ripened cheeses, with the purpose of establishing a correct cheese sampling strategy for the quantification of histamine. To this aim, histamine was determined in four distinct areas of twelve long-ripened hard cheeses: the external and internal rind, along with the outer and inner core of the wedge. The concentrations measured were remarkably different: histamine accumulated in the central core, whereas the lowest amount was found in the peripheral rind. To explain this heterogenous distribution, histamine producers were determined in the four areas by identifying the hdc sequences obtained from cheese samples. Non-starter bacteria were identified as main histamine producers; however, these microbiota were homogeneously distributed throughout the wedge. Nevertheless, the analysis of psychochemical properties of the different areas revealed an observable trend: histamine tended to accumulate in the saltier, more humid, and less oxidized areas in a wedge. Overall, this study highlights the significance of a correct sampling strategy when histamine is quantified in cheese

Removal efficiency for emerging contaminants in a WWTP from Madrid (Spain) after secondary and tertiary treatment and environmental impact on the Manzanares River

The effluents from wastewater treatment plants (WWTPs) can be an important contamination source for receiving waters. In this work, a comprehensive study on the impact of a WWTP from Madrid on the aquatic environment has been performed, including a wide number of pharmaceuticals and pesticides, among them those included in the European Watch List. 24-h composite samples of influent (IWW) and effluent wastewater after secondary (EWW2) and after secondary + tertiary treatment (EWW3) were monitored along two campaigns. Average weekly concentrations in IWW and EWW2 and EWW3 allowed estimating the removal efficiency of the WWTP for pharmaceutical active substances (PhACs). In addition, the impact of EWW3 on the water quality of the Manzanares River was assessed, in terms of PhAC and pesticide concentrations, through analysis of the river water collected upstream and downstream of the discharge point. After a preliminary risk assessment, a detailed evaluation of the impact on the aquatic environment, including a toxicological study and screening of pharmaceutical metabolites, was made for the seven most relevant PhACs: sulfamethoxazole, azithromycin and clarithromycin (antibiotics), metoprolol (antihypertensive), diclofenac (anti-inflammatory/analgesic), irbesartan (antihypertensive), and the antidepressant venlafaxine. Among selected PhACs, irbesartan, clarithromycin and venlafaxine presented moderate or high risk in the river water downstream of the discharge. Albeit no acute toxicity was detected, more detailed studies should be carried out for these substances, including additional toxicological studies, to set up potential sublethal and chronic effects on aquatic organisms.This work was developed under the financial support of DRACE INFRAESTRUCTURAS S.A. as a part of the project Estudio de contaminantes emergentes en aguas residuales y superficiales de Madrid. The authors acknowledge the support of Jose Ramon Rodriguez from DRACE INFRAESTRUCTURAS S.A., for collection of wastewater and surface water samples, as well as the discussion and useful suggestions from Jesus Angel López, Pedro Miguel Catalinas and Maria Elvira Benito, from Sub-Direccion General de Aguas, Ayuntamiento de Madrid. The University Jaume I of Castellón, Spain (project UJI-B2018-55), the Ministry of Science, Innovation and University, Spain (Ref RTI2018-097417-B-I00) and Generalitat Valenciana, Spain (research group of excellence PROMETEO 2019/040) are also acknowledged. The authors are very grateful to the Serveis Centrals d'Instrumentació Científica (SCIC) of University Jaume I for the use of LC-MS/MS instrumentation

A SPARQL Query Transformation Rule Language — Application to Retrieval and Adaptation in Case-Based Reasoning

International audienceThis paper presents SQTRL, a language for transformation rules for SPARQL queries, a tool associated with it, and how it can be applied to retrieval and adaptation in case-based reasoning (CBR). Three applications of SQTRL are presented in the domains of cooking and digital humanities. For a CBR system using RDFS for representing cases and domain knowledge, and SPARQL for its query language, case retrieval with SQTRL consists in a minimal modification of the query so that it matches at least a source case. Adaptation based on the modification of an RDFS base can also be handled with the help of this tool. SQTRL and its tool can therefore be used for several goals related to CBR systems based on the semantic web standards RDFS and SPARQL

Sound archaeology: terminology, Palaeolithic cave art and the soundscape

This article is focused on the ways that terminology describing the study of music and sound within archaeology has changed over time, and how this reflects developing methodologies, exploring the expectations and issues raised by the use of differing kinds of language to define and describe such work. It begins with a discussion of music archaeology, addressing the problems of using the term ‘music’ in an archaeological context. It continues with an examination of archaeoacoustics and acoustics, and an emphasis on sound rather than music. This leads on to a study of sound archaeology and soundscapes, pointing out that it is important to consider the complete acoustic ecology of an archaeological site, in order to identify its affordances, those possibilities offered by invariant acoustic properties. Using a case study from northern Spain, the paper suggests that all of these methodological approaches have merit, and that a project benefits from their integration

Estimación de la mortalidad atribuible a gripe estacional en España. Temporadas 1980-2008.

El objetivo de este estudio es estimar los excesos de mortalidad atribuibles a gripe estacional por grupos de edad, durante el período 1980-2008 en España, según las causas de mortalidad por "gripe y neumonía", "circulatorias y respiratorias" o "todas las causas". Se aplicó un modelo de regresión cíclica (Serfling modificado) a los datos de mortalidad obtenidos del Instituto Nacional de Estadística (INE), estimándose los excesos de defunciones mensuales atribuidas a gripe en períodos de circulación viral, con respecto a un nivel basal de mortalidad esperada en ausencia de actividad gripal, para los grupos de causas y de edad planteados. Para todas las temporadas y grupos de causas, más del 90% de los excesos de defunciones atribuibles a gripe estacional se produjeron en el grupo de mayores de 64 años. Se estimó una tasa media anual de excesos de defunciones por gripe y neumonía de 2,68 (IC 95%: 2,65; 2,71) defunciones/100.000 habitantes