Effects of maceration on the amino acid content of Chardonnay musts and wines

Chardonnay musts were macerated for 0, 6, 12, and 18 h and wines analyzed immediately after fermentation and at 6 months of bottle ageing. Maceration implies an increase of the amino acid content in the must immediately after fermentation and in the final wine. Wines from macerated musts have significantly higher levels of gamma-amino butiric acid, serine, glycine, histidine and alanine than wines from non-macerated musts. The content of these amino acids could help to examine whether there has been a maceration process or not. Must macerated for 6 h is characterized by higher contents of almost all amino acids. The only exceptions were glycine and glutamine. It is concluded that the optimum maceration time for Chardonnay must is 6 h when a maximum amino acid content is reached. After 6 months the amino acid concentrations in bottled wines were higher than in wines shortly after fermentation. Obviously the final equilibrium of amino acids had not been reached and during bottle ageing amino acids continued to be set free into the medium from yeast cells or their autolysis. During this time wines tend to reach a similar amino acid concentration independent of the maceration time of their respective musts

A multi internal standard calibration approach for the automated and robust analysis of wine volatiles by headspace Solid Phase Microextraction and further Gas Chromatography-Mass Spectrometry

Head space solid phase microextraction (HS-SPME) is a solvent-free technique that allows an almost complete automatization and getting amazing sensitivities. The hidden risk of SPME lies in the fact that as the amount of analyte extracted is very low; it is extremely sensitive to any experimental parameter that may affect the liquid-gas and gas-solid distribution coefficients. Our aims are to measure the relative weight of these factors on the lack of accuracy, and to design a robust calibration system able to avoid or limit their effects.For the first goal, synthetic but real-like wines containing a fixed amount of selected analytes (70) and variable amounts of ethanol, non-volatile constituents and major volatile constituents were prepared following a 3-Factor complete Factorial design. The study of the relevance of the Factors carried out by analysis of variance (ANOVA) and by Principal Component Analysis revealed that the levels of major volatile constituents affected the extraction of most analytes, while ethanol and matrix affected particularly low volatile compounds. Lipophilic esters are most influenced by major volatile compounds, while acids, phenols and lactones are affected by the non-volatile matrix.13 different internal standard compounds belonging to different chemical classes were used in the calibration experiment. This was similar to the aforementioned experiment, but including as well 5 different concentration levels. In 29 out of 65 cases, a single internal standard provided a robust calibration guaranteeing an accuracy better than 10%, while in others a Partial Least Square Regression analysis was run in order to find a model able to provide maxima accuracy. Satisfactory models in terms of precision, linearity and recovery could be built for 30 other compounds, so that the method can quantify up to 59 relevant wine volatile compounds

Academic literacy and student diversity: evaluating a curriculum-integrated inclusive practice intervention in the United Kingdom

The sustainability of universities is based, among other aspects, on their ability to adapt to changes and the needs of students, an increasingly diverse population. In this sense, Academic literacy provision at universities tends to be centralized and to offer language support for general academic literacy purposes rather than language development that responds in a more nuanced way to the particular literacy needs of students’ disciplines. Yet, in recent years, several studies have supported the integration of academic literacy into subject teaching outlining the principles of an inclusive model of academic literacy instruction. This paper draws on a theoretical framework developed by Wingate to evaluate a curriculum-integrated inclusive practice intervention in the United Kingdom with students from a first-year credit-bearing module at Middlesex University Business School. The study used a mixed methods approach that includes a literature review, secondary data, feedback questionnaire and a focus group to evaluate our teaching method and reflect on the collaboration of the team members to develop this inclusive pedagogical approach. The findings suggest that, on the whole, this intervention was perceived by both the module teaching team and students as positive, welcoming and often crucial for supporting undergraduate students into the disciplinary discourse of their subject of study. Yet, recommendations were made with respect to developing better guidelines for subject lecturers on how to deliver the integrated academic literacy as well as the importance of the participation of students, student learning assistants and graduate teaching assistants in the design of the intervention. This study contributes to the literature on inclusive practice intervention and pedagogical approaches to integrating academic literacy into subject teaching for a diverse student population, contributing to the social sustainability of the universities

A dual-sensing thermo-chemical ISFET array for DNA-based diagnostics.

This paper presents a 32x32 ISFET array with in-pixel dual-sensing and programmability targeted for on-chip DNA amplification detection. The pixel architecture provides thermal and chemical sensing by encoding temperature and ion activity in a single output PWM, modulating its frequency and its duty cycle respectively. Each pixel is composed of an ISFET-based differential linear OTA and a 2-stage sawtooth oscillator. The operating point and characteristic response of the pixel can be programmed, enabling trapped charge compensation and enhancing the versatility and adaptability of the architecture. Fabricated in 0.18 μm standard CMOS process, the system demonstrates a quadratic thermal response and a highly linear pH sensitivity, with a trapped charge compensation scheme able to calibrate 99.5% of the pixels in the target range, achieving a homogeneous response across the array. Furthermore, the sensing scheme is robust against process variations and can operate under various supply conditions. Finally, the architecture suitability for on-chip DNA amplification detection is proven by performing Loop-mediated Isothermal Amplification (LAMP) of phage lambda DNA, obtaining a time-to-positive of 7.71 minutes with results comparable to commercial qPCR instruments. This architecture represents the first in-pixel dual thermo-chemical sensing in ISFET arrays for Lab-on-a-Chip diagnostics

Estimation of the aroma potential of Grapes

Wine suffers important chemical transformations since the end of the fermentation process tillthe moment of consumption, whose object is the stabilization and maturation and fining ofwine organoleptic character. Within this context, the goal of the work is to understand thewine ageing process as a result of different enological variables involved in the formation ofsensory active molecules in wine. In particular, we aim to study the potential aromaticcomposition of wine as a function of its aroma precursor content along with the generationand degradation kinetics under the ageing conditions occurring in wine. For this purpose aseries of model solutions supplemented with, either flavor precursors extracted from differentgrape varieties, or with pure aromatic compounds, were submitted to an accelerated ageing(45ºC for 60 days) simulating maturation in the bottle. Volatile compounds derived from grapeflavor precursors were extracted by SPE and determined by GC‐MS after diferent times ofageing. The model wine spiked with the pure aromatic compounds was employed to monitorthe hydrolysis kinetics and compounds stability. On the other hand, in the solution spiked withflavor precursors, major differences in concentration were observed during the first week ofaccelerated ageing. Most compounds exhibited an initial significant increase and furthersteady decrease in their concentrations. Results from this experiment were employed toestablish a mathematical model to determine the number of aromatic compounds present atdifferent moments of the ageing process

The toxicity and intraspecific variability of Alexandrium andersonii Balech

The toxicity of Alexandrium andersonii Balech is unclear and its intraspecific variability has yet to be studied. To address these gaps in our knowledge, in the present work five strains of A. andersonii from four different localities were characterized. The results showed that despite genetic homogeneity in the 5.8-ITS (internal transcribed spacer) and large subunit (LSU) regions and similar growth rates, strains originating from different locations varied with respect to cell size, the ratios of certain pigments, and their growth patterns. Cultures of the strains grown at 20 8C were analyzed for toxicity using four different methodologies. The two officially established methods, mouse bioassay and high-performance liquid chromatography with fluorescence detection (HPLC-FLD) and post-column reaction analysis of PSP toxins, failed to show the toxicity of any strain. Strains grown at 14 8C were also negative for PSP toxins by HPLC-FLD. However, strains grown at 20 8C exhibited both a response characteristic of the presence of toxin-inhibiting voltage-gated sodium channels, as demonstrated in a neuroblastoma neuro- 2a cell-based assay, as well as hemolytic activity in a sheep red blood cell assay

The Effects of the Atmospheric Pressure Changes on Seismic Signals or How to Improve the Quality of a Station

Seismic investigations are mainly limited by seismic noise. Two microbarometers have been installed in the seismic vault of two different GEOSCOPE stations, one at SSB and the other at TAM. All vertical components and most of the horizontal components show a significant correlation with pressure. In order to correct the seismic signals from the atmospheric pressure noise, a transfer function between the pressure data and the seismic data is inverted. Results show that, after correction, the noise levels reached on the horizontal components are similar between the two stations, and the vertical components display noise levels below the low-noise model as defined by Peterson (1993). This technique reduces part of the noise and allows detection of small earthquakes and a better extraction of normal modes. The analysis of the lowest normal modes of the Earth excited by the M_S = 8.2 Macquarie Island earthquake is given to illustrate the perspectives of the method

Amplification curve analysis: Data-driven multiplexing using real-time digital PCR

Information about the kinetics of PCR reactions are encoded in the amplification curve. However, in digital PCR (dPCR), this information is typically neglected by collapsing each amplification curve into a binary output (positive/negative). Here, we demonstrate that the large volume of raw data obtained from realtime dPCR instruments can be exploited to perform data-driven multiplexing in a single fluorescent channel using machine learning methods, by virtue of the information in the amplification curve. This new approach, referred to as amplification curve analysis (ACA), was shown using an intercalating dye (EvaGreen), reducing the cost and complexity of the assay and enabling the use of melting curve analysis for validation. As a case study, we multiplexed 3 carbapenem-resistant genes to show the impact of this approach on global challenges such as antimicrobial resistance. In the presence of single targets, we report a classification accuracy of 99.1% (N = 16188) which represents a 19.7% increase compared to multiplexing based on the final fluorescent intensity. Considering all combinations of amplification events (including coamplifications), the accuracy was shown to be 92.9% (N = 10383). To support the analysis, we derived a formula to estimate the occurrence of co-amplification in dPCR based on multivariate Poisson statistics, and suggest reducing the digital occupancy in the case of multiple targets in the same digital panel. The ACA approach takes a step towards maximizing the capabilities of existing real-time dPCR instruments and chemistries, by extracting more information from data to enable data-driven multiplexing with high accuracy. Furthermore, we expect that combining this method with existing probe-based assays will increase multiplexing capabilities significantly. We envision that once emerging point-of-care technologies can reliably capture real-time data from isothermal chemistries, the ACA method will facilitate the implementation of dPCR outside of the lab

Determinación de los perfiles sensoriales característicos de la aceituna Aloreña

Aloreña olives are unique to and typical of the Guadalhorce region (Málaga, Spain). They possess some specific characteristics which make them an excellent product that is differentiated from the other olive varieties. The sensory profile technique was used to study the sensory attributes which best characterize the three processing styles of Aloreña table-olives. The characteristic descriptors are identified according to the round-table method and multivariate analysis. Sensory profile data obtained were analyzed using a mix of Nested Design ANOVA and Factorial ANOVA and by a canonical analysis. The effect of the factor processing style was significant only for three descriptors: fruit odor, bitter taste and firmness (p < 0.05) whereas the effect of the samples nested in each processing style was significant for all the attributes (p < 0.001). Duncan’s post hoc test and the canonical analysis showed that all samples were different within each processing style.La aceituna Aloreña es una variedad de aceituna de mesa autóctona de la comarca del Valle del Guadalhorce (Málaga, España) que posee unas características propias que la distingue del resto de variedades, siendo las propiedades sensoriales las que mejor la diferencian. Para estudiar los atributos sensoriales que mejor definen a los tres tipos de elaboración de la aceituna Aloreña (verdes frescas, tradicionales y curadas) se utiliza la técnica del perfil sensorial. La selección de atributos sensoriales se realiza mediante discusión grupal en mesa redonda y utilizando análisis multivariante. Los datos obtenidos de los perfiles sensoriales se analizan utilizando un modelo mixto de análisis de la varianza (anidado x factorial) y un análisis canónico. Los resultados del análisis de varianza indican que las principales diferencias entre estilos de elaboración se deben a los atributos frutado, sabor amargo y firmeza (p < 0.05) y que las diferencias entre muestras, dentro de cada estilo de elaboración, se deben a todos los atributos estudiados (p < 0.001). El test de medias de Duncan y el análisis canónico muestran que todas las muestras son diferentes dentro de cada estilo de elaboración