Evaluation by Flash GC Electronic Nose of the Effect of Combinations of Yeasts and Nutrients on the Aromatic Profiles of Feteasca Regala Wines after Two Years of Storage

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 223
Author(s):  
Arina Oana Antoce ◽  
George Adrian Cojocaru
Keyword(s):  
Electronic Nose ◽  
Volatile Profile ◽  
Grape Variety ◽  
Software Module ◽  
Good Discrimination ◽  
Natural Fermentation ◽  
Chromatographic Columns ◽  
Technological Interventions ◽  
Different Strains ◽  
The Impact

Feteasca regala is a semi-aromatic Romanian white grape variety, which can benefit from technological interventions aiming to modulate its aromatic profile. In this study, two specific yeast nutrients, designed to increase the esteric and thiolic aromatic potential, respectively, were added at appropriate times, before or during fermentation. The musts were inoculated with two different strains of yeast, specially selected to favour the formation of an esteric or a thiolic volatile profile. The resulting wines were bottled and analysed two years later by Heracles flash GC electronic nose (from Alpha MOS), which provided a good discrimination of the samples based on the peaks of volatile molecules identified on the two chromatographic columns. The electronic nose showed that, in the aged wines, the influence of the yeast inoculated for fermentation was more evident than the impact of the yeast nutrients added. Using the AroChemBase software module from Alpha MOS, some volatile esters and other compounds were identified, and their importance for the discrimination of the wines and for the aroma profile is discussed. However, because the GC electronic nose can identify only some volatile compounds, but not all, sensory analysis was also applied to evaluate the wine samples, showing that the yeast, as well as the nutrients, have a clear influence on the perceived aromatic profiles. As intended, samples prepared with any of the technological interventions showed different volatile/aromatic profiles than the control wine prepared by natural fermentation and were clearly separated by the electronic nose, even after two years of storage. However, due to the limitations of the chromatographic columns used, the electronic nose could not provide an overall description of the aromatic profile of the produced wines, which is why the expertise of panelists was still needed to evaluate wines.

A Report on COVID-19 Variants, COVID-19 Vaccines and the Impact of the Variants on the Efficacy of the Vaccines

2021 ◽  
Author(s):  
Michael Halim
Keyword(s):  
South Africa ◽  
Immune Response ◽  
Clinical Characteristics ◽  
Systemic Review ◽  
Review Of Literature ◽  
Negative Effects ◽  
Mortality And Morbidity ◽  
The World ◽  
Different Strains ◽  
The Impact

The Coronavirus pandemic has caused negative effects across the globe; mortality and morbidity being the main impact. After WHO, termed the disease a pandemic in March 2020, they gave in health guidelines to follow to control the spread of the disease. The health industry, academia, and different governments are united to develop and test various vaccines at an unprecedented speed to combat the pandemic fully and bring the world back to its feet. Some of the vaccines developed include Pfizer, Moderna, and AstraZeneca. However, just like other viruses, the SAR-CoV-2 virus keeps changing through mutation, as various variants, different from the first one are emerging. Evidence shows that the three new variants; UK, Brazil, and South Africa are more severe in terms of transmissibility, disease severity, evading of the immune response, and reducing the ability to neutralized antibodies, compared to the original coronavirus. With such knowledge of the existence of different strains, the arises concerns on whether the already available vaccines are effective enough in preventing the new COVID-19 strains. Studies are still underdeveloped to learn more on the virologic, epidemiologic, and clinical characteristics of the ever-emerging variants. This research, through a systemic review of literature, seeks to find out whether the variants of SAR-CoV-2 have an impact on the efficacy of various vaccines developed in fighting the disease and the entire body’s immune response.

scholarly journals A linearized non-isothermal general rate model for studying thermal effects in liquid chromatographic columns

2020 ◽  
pp. 336-336
Author(s):  
Nadia Kiran ◽  
Sadia Perveen ◽  
Seemab Bashir ◽  
Shamsul Qamar
Keyword(s):  
Differential Equations ◽  
Numerical Test ◽  
Fixed Bed ◽  
Packed Bed ◽  
Eigenvalue Decomposition ◽  
Finite Volume Scheme ◽  
Rate Model ◽  
Chromatographic Columns ◽  
Liquid Chromatographic ◽  
The Impact

A linearized non-isothermal general rate model is formulated and analytically solved to quantify the effects of temperature variations in fixed-bed chromatographic columns. The model contains a set of four coupled partial differential equations (PDEs) accounting for energy transfer resistances, inner and outer particle-pore diffusions, and interfacial mass and axial dispersion. The Laplace transform, the eigenvalue-decomposition technique, and a conventional technique for the solutions of ordinary differential equations (ODEs) are jointly employed for the solution of the model equations. A few numerical test studies are considered to assess the impact of system parameters on the performance of packed-bed adsorption columns. To access the range of applicability and to get the scope of the appropriateness of calculated analytical results, the numerical results are also obtained by applying a high resolution finite volume scheme (HR-FVS). The analytical solutions obtained can be used as an invaluable tool for analyzing, optimizing, and upgrading the non-isothermal liquid chromatographic procedures.

scholarly journals Development of a Tuneable NDIR Optical Electronic Nose

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6875
Author(s):  
Siavash Esfahani ◽  
Akira Tiele ◽  
Samuel O. Agbroko ◽  
James A. Covington
Keyword(s):  
Electronic Nose ◽  
Gas Sensors ◽  
Low Cost ◽  
Medical Diagnostics ◽  
Good Discrimination ◽  
Humidity Effects ◽  
Sensor Drift ◽  
Optical Gas Sensor ◽  
Series Of Experiments ◽  
Increasing Demand

Electronic nose (E-nose) technology provides an easy and inexpensive way to analyse chemical samples. In recent years, there has been increasing demand for E-noses in applications such as food safety, environmental monitoring and medical diagnostics. Currently, the majority of E-noses utilise an array of metal oxide (MOX) or conducting polymer (CP) gas sensors. However, these sensing technologies can suffer from sensor drift, poor repeatability and temperature and humidity effects. Optical gas sensors have the potential to overcome these issues. This paper reports on the development of an optical non-dispersive infrared (NDIR) E-nose, which consists of an array of four tuneable detectors, able to scan a range of wavelengths (3.1–10.5 μm). The functionality of the device was demonstrated in a series of experiments, involving gas rig tests for individual chemicals (CO2 and CH4), at different concentrations, and discriminating between chemical standards and complex mixtures. The optical gas sensor responses were shown to be linear to polynomial for different concentrations of CO2 and CH4. Good discrimination was achieved between sample groups. Optical E-nose technology therefore demonstrates significant potential as a portable and low-cost solution for a number of E-nose applications.

scholarly journals New Insights into the Oenological Significance of Candida zemplinina: Impact of Selected Autochthonous Strains on the Volatile Profile of Apulian Wines

2020 ◽  
Vol 8 (5) ◽  
pp. 628 ◽  
Author(s):  
Pasquale Russo ◽  
Maria Tufariello ◽  
Raffaela Renna ◽  
Mariana Tristezza ◽  
Marco Taurino ◽  
...  
Keyword(s):  
Intraspecific Variability ◽  
Starter Cultures ◽  
Gas Chromatography Mass Spectrometry ◽  
Volatile Profile ◽  
Glycerol Production ◽  
Odor Thresholds ◽  
Volatile Profiles ◽  
The Impact ◽  
Grape Musts ◽  
Specific Impact

In this investigation, we explored the oenological significance of Candida zemplinina (syn. Starmerella bacillaris) isolates from Apulian grape musts. Moreover, we provide the first evidence of the impact of different C. zemplinina strains on the wine aromatic properties tested as monocultures. We described the diversity of C. zemplinina strains isolated from grapes and the variability of ‘volatile’ phenotypes associated with this intraspecific variability. Thirty-three isolates were characterized at strain level by PCR-based approach and, among these, 16 strains were identified and then tested by microfermentation tests carried out in grape must. Analyzed strains were low producers of acetic acid and hydrogen sulphide, not able to decarboxylate a panel of representative amino acids, whereas they showed fructophilic character and significant glycerol production. Volatile profiles of produced wines were investigated by gas chromatography–mass spectrometry. The Odor Activity Values of all molecules were calculated and 12 compounds showed values above their odor thresholds. Two selected strains (35NC1 and 15PR1) could be considered as possible starter cultures since they were able to positively affect the sensory properties of obtained wine. This report firstly supplies evidence on the strain-specific impact of different C. zemplinina strains on the final aroma of produced wines.

scholarly journals Madeira Wine Volatile Profile. A Platform to Establish Madeira Wine Aroma Descriptors

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3028 ◽  
Author(s):  
Rosa Perestrelo ◽  
Catarina Silva ◽  
José S. Câmara
Keyword(s):  
Solid Phase ◽  
Point Of View ◽  
Gas Chromatography Mass Spectrometry ◽  
Wine Aroma ◽  
Grape Variety ◽  
Volatile Phenols ◽  
Starting Point ◽  
Furanic Compounds ◽  
The Impact ◽  
And Diffusion

In the present study we aimed to investigate the volatile organic compounds (VOCs) that may potentially be responsible for specific descriptors of Madeira wine providing details about Madeira wine aroma notes at molecular level. Moreover, the wine aroma profile, based on the obtained data, will be a starting point to evaluate the impact of grape variety (Malvasia, Bual, Sercial, Verdelho and Tinta Negra), type (sweet, medium sweet, dry and medium dry), and age (from 3 to 20 years old) on Madeira wine sensorial properties. Firstly, a comprehensive and in-depth Madeira wine volatile profiling was carried out using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS–SPME/GC–qMS). Secondly, a relation among the varietal, fermentative and aging aroma compounds, and their aroma descriptors with the Madeira wine sensorial properties was assessed. A total of 82 VOCs, belonging to different chemical families were identified, namely 21 esters, 13 higher alcohols, ten terpenic compounds, nine fatty acids, seven furanic compounds, seven norisoprenoids, six lactones, four acetals, four volatile phenols and one sulphur compound. From a sensorial point of view, during the aging process the wine lost its freshness and fruitiness odor related to the presence of some varietal and fermentative compounds, whereas other descriptors such as caramel, dried fruits, spicy, toasty and woody, arose during ageing. The Maillard reaction and diffusion from the oak were the most important pathways related with these descriptors. A relationship-based approach was used to explore the impact of grape variety, wine type, and age on Madeira wine sensorial properties based on shared number of VOCs and their odors.

Feasibility of an electronic nose to differentiate commercial Spanish wines elaborated from the same grape variety

2013 ◽  
Vol 51 (2) ◽  
pp. 790-796 ◽  
Author(s):  
María de las Nieves López de Lerma ◽  
Andrea Bellincontro ◽  
Teresa García-Martínez ◽  
Fabio Mencarelli ◽  
Juan José Moreno
Keyword(s):  
Electronic Nose ◽  
Grape Variety

PERMUTATION ENTROPY APPLIED TO MOVEMENT BEHAVIORS OF DROSOPHILA MELANOGASTER

2011 ◽  
Vol 25 (12n13) ◽  
pp. 1133-1142 ◽  
Author(s):  
YUEDAN LIU ◽  
TAE-SOO CHON ◽  
HUNKI BAEK ◽  
YOUNGHAE DO ◽  
JIN HEE CHOI ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Cross Correlation ◽  
Movement Patterns ◽  
Behavioral Changes ◽  
Permutation Entropy ◽  
One Dimensional ◽  
Vertical Data ◽  
Position Data ◽  
Different Strains ◽  
The Impact

Movement of different strains in Drosophila melanogaster was continuously observed by using computer interfacing techniques and was analyzed by permutation entropy (PE) after exposure to toxic chemicals, toluene (0.1 mg/m3) and formaldehyde (0.01 mg/m3). The PE values based on one-dimensional time series position (vertical) data were variable according to internal constraint (i.e. strains) and accordingly increased in response to external constraint (i.e. chemicals) by reflecting diversity in movement patterns from both normal and intoxicated states. Cross-correlation function revealed temporal associations between the PE values and between the component movement patterns in different chemicals and strains through the period of intoxication. The entropy based on the order of position data could be a useful means for complexity measure in behavioral changes and for monitoring the impact of stressors in environment.

scholarly journals Stepwise linear discriminant analysis to differentiate Spanish red wines by their Protected Designation of Origin or category using physico-chemical parameters

OENO One ◽  
2020 ◽  
Vol 54 (1) ◽  
pp. 86-99
Author(s):  
Rubén Del Barrio Galán ◽  
Marta Bueno Herrera ◽  
Pedro López de la Cuesta ◽  
Silvia Pérez-Magariño
Keyword(s):  
Discriminant Analysis ◽  
Linear Discriminant Analysis ◽  
Average Molecular Weight ◽  
Red Wines ◽  
Grape Variety ◽  
Chemical Parameters ◽  
Good Discrimination ◽  
Linear Discriminant ◽  
Protected Designation Of Origin ◽  
Physico Chemical

Aim: The aim of this work was to determine the physico-chemical variables that differentiating red wines from the “Castilla y León” Spanish region by their Protected Designation of Origin (PDO) and wine category ("young", “oak”, “crianza”, or “reserve”).Methods and results: A total of 135 commercial red wines from four Spanish PDOs in the region of Castilla and León were analysed. Forty physico-chemical parameters, related to classical enological parameters, phenolic and polysacharidic composition, and content of higher alcohols were evaluated. Differences in physico-chemical composition were found in red wines from different PDOs and different categories. Stepwise linear discriminant analysis (SLDA) was applied to find a linear combination of the physico-chemical variables that separate and classify the red wines according to the PDO or category. One SLDA model selected 15 physico-chemical variables that allowed for good discrimination and classification of the wines from different PDOs. The SLDA model selected seven variables for wine category differentiation, but only allowed for good discrimination between young wines and aged wines (“crianza” and “reserve”).Conclusions: The variables that contributed most to the separation of Tempranillo red wines were total polyphenols, total tannins, and absorbance values at 230 nm and 280 nm. The polysaccharides with an average molecular weight of 10 kDa, flavanols, stilbenes and 2-methyl-1-butanol were those most associated with the differentiation of the wines elaborated with the Mencía grape variety. The percentage of polymeric anthocyanins and absorbance at 230 nm could be proposed as good indicators for aged wines, and total tannins for young wines.Significance and impact of the study: This study provides improved knowledge of the physico-chemical variables that could be used as markers of the origin of wines and/or the grape variety (Tempranillo and Mencía) and that allow differentiating young wines from those aged for a long time.

scholarly journals Material Screening for Gas Sensing using an Electronic Nose: Gas Sorption Thermodynamic and Kinetic Considerations

2021 ◽  
Author(s):  
Ashwin Kumar Rajagopalan ◽  
Camille Petit
Keyword(s):  
Electronic Nose ◽  
Gas Flow ◽  
Sensor Array ◽  
Thermodynamic Characteristics ◽  
Material System ◽  
Gas Composition ◽  
Kinetic Characteristics ◽  
Gas Sorption ◽  
The Impact ◽  
Material Screening

To detect multiple gases in a mixture, one must employ an electronic nose or sensor array, composed of several materials as a single material cannot resolve all the gases in a mixture accurately. Given the many candidate materials, choosing the right combination of materials to be used in an array is a challenging task. In a sensor whose sensing mechanism depends on a change in mass upon gas adsorption, both the equilibrium and kinetic characteristics of the gas-material system dictate the performance of the array. The overarching goal of this work is two-fold. First, we aim to highlight the impact of thermodynamic characteristics of gas-material combination on array performance and to develop a graphical approach to rapidly screen materials. Second, we aim to highlight the need to incorporate the gas sorption kinetic characteristics to provide an accurate picture of the performance of a sensor array. To address these goals, we have developed a computational test bench that incorporates a sensor model and a gas composition estimator. To provide a generic study, we have chosen, as candidate materials, hypothetical materials that exhibit equilibrium characteristics similar to metal organic frameworks (MOFs). Our computational studies led to key learnings, namely: (1) exploit the shape of the sensor response as a function of gas composition for material screening purposes for gravimetric arrays; (2) incorporate both equilibrium and kinetics for gas composition estimation in a dynamic system; and (3) engineer the array by accounting for the kinetics of the materials, the feed gas flow rate, and the size of the device.

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