Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 5.307
Filtrar
1.
Food Chem ; 334: 127386, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32712494

RESUMO

Elemental composition was used to characterize and differentiate 14 wines made from the identical clone of Vitis vinifera cv. Pinot noir (clone 667). The vineyards span distances which range from several hundred meters to 1540 km and their elevations vary from near sea level to nearly 500 m. Twenty-seven elements were observed above the limit of quantitation by using inductively coupled plasma mass spectrometry (ICP-MS) in the wines from at least half of the 14 sites. Concentrations of several elements, including Mo, Er, Na, Li, Cs and Pb, varied by 10-fold across the 14 wines. Multiple factor analysis (MFA) of elemental composition with juice chemistry and site characterization show associations consistent with expectations, such as high Ca with high clay content. These results demonstrate that even when grapevine clone and winemaking protocol are controlled, composition differences in wines produced from sites are mediated by diverse soil and microclimate conditions.


Assuntos
Metais/análise , Vitis , Vinho/análise , California , Fazendas , Espectrometria de Massas , Microclima , Solo/química , Vitis/química , Vitis/crescimento & desenvolvimento
2.
Food Chem ; 335: 127592, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32750629

RESUMO

With the increased risk of wine fraud, a rapid and simple method for wine authentication has become a necessity for the global wine industry. The use of fluorescence data from an absorbance and transmission excitation-emission matrix (A-TEEM) technique for discrimination of wines according to geographical origin was investigated in comparison to inductively coupled plasma-mass spectrometry (ICP-MS). The two approaches were applied to commercial Cabernet Sauvignon wines from vintage 2015 originating from three wine regions of Australia, along with Bordeaux, France. Extreme gradient boosting discriminant analysis (XGBDA) was examined among other multivariate algorithms for classification of wines. Models were cross-validated and performance was described in terms of sensitivity, specificity, and accuracy. XGBDA classification afforded 100% correct class assignment for all tested regions using the EEM of each sample, and overall 97.7% for ICP-MS. The novel combination of A-TEEM and XGBDA was found to have great potential for accurate authentication of wines.


Assuntos
Geografia , Vinho/análise , Austrália , Modelos Estatísticos , Espectrometria de Fluorescência
3.
Food Chem ; 337: 127720, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32777572

RESUMO

The sensorial and chemical differences among Pinot noir wines from different vineyard locations were investigated. Grapes of a single Pinot noir clone were grown on twelve different vineyard sites along the U.S. West Coast. Wines from a single vintage (2015) were made using a standardized protocol and equipment. Sensorial (i.e. aroma, taste, and mouthfeel) and chemical (i.e. polyphenolic and volatile) differences were observed among these wines at two aging time points (8- and 20- months). Vineyard location (i.e. latitude and longitude) was one of the main factors describing the major differences between the wines, while other details (i.e. soil type (60 cm), rootstock age, soil pH, rootstock type, and vines/acres) were possibly important for defining unique aging characteristics of certain vineyards. Overall, single clone Pinot noir grapes grown in different regions but made under standardized winemaking produced wines with unique chemical and sensorial profiles, which generally persisted throughout aging.


Assuntos
Paladar , Vitis/química , Vitis/crescimento & desenvolvimento , Vinho/análise , Fazendas , Solo , Estados Unidos , Compostos Orgânicos Voláteis/análise
4.
J Chromatogr A ; 1626: 461383, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797856

RESUMO

The potential of Micellar Electrokinetic Chromatography to achieve enantiomeric separations is reviewed in this article. The separation principles and the most frequently employed separation strategies to achieve chiral separations by Micellar Electrokinetic Chromatography are described. The use of chiral micellar systems alone or combined with other micellar systems or chiral selectors, as well as of mixtures of achiral micellar systems with chiral selectors is discussed together with the effect of different additives present in the separation medium. Indirect methods based on the derivatization of analytes with chiral derivatizing reagents and the use of achiral micelles are also considered. Preconcentration techniques employed to improve sensitivity and the main approaches developed to facilitate the coupling with Mass Spectrometry are included. The most recent and relevant methodologies developed by chiral Micellar Electrokinetic Chromatography and their applications in different fields are presented.


Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , Aminoácidos/química , Ciclodextrinas/química , Análise de Alimentos , Espectrometria de Massas , Oryza/química , Oryza/metabolismo , Estereoisomerismo , Vinho/análise
5.
J Chromatogr A ; 1629: 461464, 2020 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-32841772

RESUMO

Red wine is a complex matrix containing macromolecules such as condensed tannins and polysaccharides. Wine macromolecular components and their interactions have been reported to impact taste properties such as astringency but the colloidal systems formed in wine are not well known. A key prerequisite to characterize these systems is the ability to work under analytical conditions as close as possible to the colloid environment, preserving the sample structure and limiting the denaturation of macromolecular complexes. A method of Asymmetric Flow Field-Flow Fractionation (AF4) coupled with UV detection, multi-angle light scattering (MALS), and differential refractometer index (dRI) (AF4-UV-MALS-dRI) has been developed to analyse macromolecules, including tannins and polysaccharides, and macromolecular complexes, in red wine. This method separates objects according to their hydrodynamic radius and does not require calibration to determine molecular weight (Mw). AF4 can provide native separation of wine colloidal matter while working with simulated wine as mobile phase. The channel was equipped with a 350-µm spacer and the membrane made in regenerated cellulose had a cut-off of 5kDa. Different parameters of crossflow rate were investigated using a generic red wine to optimize separation conditions. Then, purified fractions of polysaccharides and tannins were analysed using the selected AF4 parameters. The comparison of the peaks obtained for these fractions and for the wine sample allowed us to determine the retention time associated with these macromolecules. The AF4 fractogram of wine was divided into four fractions. The first three were assigned to higher Mw tannins coeluted with lower Mw polysaccharides such as rhamnogalacturonan II (F1), to intermediate Mw polysaccharides (F2), and to higher Mw mannoproteins (F3) whereas the last fraction (F4) was not identified. Furthermore, our results have shown that AF4-UV-MALS-dRI could be an efficient technique to separate large size tannins as well as polysaccharides and macromolecular complexes.


Assuntos
Fracionamento por Campo e Fluxo/métodos , Substâncias Macromoleculares/isolamento & purificação , Polifenóis/isolamento & purificação , Vinho/análise , Hidrodinâmica , Peso Molecular , Polissacarídeos/isolamento & purificação , Taninos/isolamento & purificação , Fatores de Tempo
6.
J Oleo Sci ; 69(8): 929-939, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32759551

RESUMO

Glucosylceramide (GlcCer), a major sphingolipid in plants and fungi, is known to have food functions, such as preventing intestinal impairment and enhancing the moisture content of skin. This study investigated the influence of fermentation on the composition and function of lipophilic components containing GlcCer in plant-based foods; we compared the effects of ethanol extracts from sake rice (SR) and sake lees (SL) on colon impairment in mice. GlcCer and ceramide (Cer) levels in SL were much higher than those in SR, and GlcCer in SL contained 9-methyl-trans-4,trans-8-sphingadienine as a fungi-specific sphingoid base. 1,2-dimethylhydrazine (DMH) treatment markedly increased the formation of aberrant crypt foci (ACF) and the levels of TNF-α and lipid oxidation in mice colons. However, dietary SR or SL significantly suppressed these DMH-induced changes, and SR demonstrated stronger effects than SL. In addition, dietary SR or SL suppressed the expression of apoptotic and anti-apoptotic proteins induced by DMH treatment. This study suggests that SR or SL intake could reduce colon ACF formation via the suppression of inflammation and oxidation-induced cell cycle disturbances. When compared to SR, the weaked effects of SL rich in GlcCer may be the result of the changes in sphingolipid composition (sphingoid base and Cer) and differences in the concentration of other bioactive compounds produced or digested during fermentation.


Assuntos
Focos de Criptas Aberrantes/prevenção & controle , Neoplasias do Colo/prevenção & controle , Glucosilceramidas/análise , Glucosilceramidas/farmacologia , Oryza/química , Fitoterapia , Extratos Vegetais/análise , Extratos Vegetais/farmacologia , Vinho/análise , Focos de Criptas Aberrantes/metabolismo , Focos de Criptas Aberrantes/patologia , Administração Oral , Animais , Apoptose , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Modelos Animais de Doenças , Etanol , Feminino , Fermentação , Glucosilceramidas/administração & dosagem , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Camundongos Endogâmicos BALB C , Extratos Vegetais/administração & dosagem , Fator de Necrose Tumoral alfa/metabolismo
7.
Food Chem ; 333: 127455, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32653683

RESUMO

Ultrasound (US) has been recognized as a non-thermal technology for accelerating blueberry wine aging for flavor development. However, influence of US on anthocyanin and color characteristics is uncertain. In this study, US was applied to new blueberry wine, and changes in color characteristics, anthocyanin content and anti-oxidant capacity were evaluated at early stage of aging period. Low-frequency power US resulted in an improvement in color characteristics and lower chromatic aberration as compared to untreated samples, specially at condition of 180 W, 20 min and 2 cycles. Furthermore, this contribution was attributed to unattenuated anthocyanins protected from US stress. Importantly, the structural polarity dependence was mediated by the impact of US on anthocyanins. Additionally, anti-oxidant activity of blueberry wine was not adversely affected under a moderate US condition. US treatment of blueberry wine was therefore considered to significantly enhance the color presentation, hinting at the possibility of promoting blueberry wine aging.


Assuntos
Antocianinas/química , Antioxidantes/química , Mirtilos Azuis (Planta) , Ultrassom/métodos , Vinho , Antocianinas/análise , Antioxidantes/análise , Mirtilos Azuis (Planta)/química , Cor , Indústria de Processamento de Alimentos/métodos , Vinho/análise
8.
Zhongguo Zhong Yao Za Zhi ; 45(11): 2552-2559, 2020 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-32627488

RESUMO

Scutellariae Radix(Huangqin) is a well-known traditional Chinese medicine(TCM) used for the treatment of clearing heat in clinical application. It is bitter-cold by using directly, but the bitter-cold property can be relieved after wine-frying. The study of taste changes before and after wine-frying of Scutellariae Radix is of great significance in identifying Scutellariae Radix and wine-processed Scutellariae Radix and clarifying the traditional theory of wine-processing. In this experiment, 10 batches of Scutellariae Radix and wine-processed Scutellariae Radix were prepared. The contents of 5 flavonoids were determined by high performance liquid chromatography(HPLC), and principal component analysis(PCA) was performed with 5 flavonoids as variables. As a result, the contents were different in different batches of Scutellariae Radix, but Scutellariae Radix and wine-processed Scutellariae Radix could not be distinguished. Five sensory attributes(sour, salty, fresh, sweet, and bitter) were evaluated by artificial tasting, and the response values of 7 sensors(AHS, AHS, PKS, CTS, NMS, CPS, ANS, SCS) representing the taste of pieces were detected by electronic tongue. The correlation between sensory evaluation and response values of the electronic tongue were analyzed, and the results showed that the sensory evaluation of sour, salty, fresh, sweet, bitter and AHS, CTS, NMS, ANS, SCS sensors had different degrees of correlation, indicating that the electronic tongue technology can be used as an alternative to artificial taste and can serve as a means for quantifying the taste, and it can be used to evaluate the taste of TCM pieces. The taste method was used to analyze the response values of the electronic tongue, and the results showed that the bitterness of wine-processed Scutellariae Radix decreased and the salty taste increased. PCA was used to analyze taste changes before and after wine-processed Scutellariae Radix, and the results showed that taste differences between 2 pieces were divided into 2 categories. PCA loading scattering plots showed that response of saltiness and bitterness were the major factors to affect overall taste in Scutellariae Radix and wine-processed Scutellariae Radix. Based on electronic tongue response values, the Fisher discriminant model for Scutellariae Radix and wine-processed Scutellariae Radix was established, which showed that it could effectively discriminate them with a recognition rate of 100%. The experimental results showed that the electronic tongue combined with multivariate statistical analysis can be used to evaluate taste of TCM, at the same time, it could provide a fast and simple method for identifying different processed products.


Assuntos
Scutellaria baicalensis , Vinho/análise , Cromatografia Líquida de Alta Pressão , Medicina Tradicional Chinesa , Paladar
9.
J Chromatogr A ; 1625: 461226, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709310

RESUMO

In this work, an easy and fast procedure for the selective multiresidue determination of 14 highly polar pesticides (including glyphosate, glufosinate, ethephon and fosetyl) and metabolites in beverages is presented. After an initial sample dilution (1:1, v/v), the extract is shaken and centrifuged, further diluted and then injected directly into the LC-MS/MS system, using hydrophilic interaction liquid chromatography (HILIC) and tandem mass spectrometry. No clean-up procedure was needed. The method was validated according to the current European guidelines for pesticide residue analysis in food and feed and linearity, limits of detection and quantification, matrix effects, trueness and precision were assessed. For plant-based milk, wine and beer samples, 10, 11 and 12 analytes, respectively, out of 14 were fully validated at 10 µg kg-1, the lowest spike level tested. The matrix effect was negative in most of the cases, showing for some compounds, such as HEPA, up to 80% suppression when compared to the response from standards in solvent. The use of isotopically labelled internal standards is required for the optimal quantification, as it compensates for high and varying matrix effects and also for recovery losses during extraction.


Assuntos
Cerveja/análise , Cromatografia Líquida de Alta Pressão/métodos , Substitutos do Leite/química , Resíduos de Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Vinho/análise , Animais , Ânions/química , Interações Hidrofóbicas e Hidrofílicas , Leite de Soja/química
10.
Food Chem ; 333: 127450, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32663749

RESUMO

The aged wine spirit is a beverage with great aromatic complexity. Their volatile compounds with odorant power coming from the distillate and from the wood used in its ageing, and the interactions that take place in the process, enhanced by oxygen, all contribute to this complexity. Due to time and cost inherent of ageing wine spirits in wooden barrels, research has sought to develop more sustainable alternatives to do it. In this context, the present study compares, the effect of traditional (wooden barrel) and alternative system (stainless steel tank with dipped staves and micro-oxygenation), on the odorant and sensory profile of a wine spirit, using Limousin oak and chestnut wood, after 12 months of ageing. The results suggest that the ageing process is accelerated by the alternative ageing technology and the chestnut wood, and the corresponding wine spirits presented characteristics of greater sensory evolution and strong wood compounds extraction.


Assuntos
Indústria de Processamento de Alimentos/métodos , Odorantes , Vinho , Madeira , Adulto , Aesculus , Idoso , Feminino , Indústria de Processamento de Alimentos/instrumentação , Humanos , Masculino , Pessoa de Meia-Idade , Odorantes/análise , Oxigênio/química , Quercus , Aço Inoxidável , Fatores de Tempo , Compostos Orgânicos Voláteis/análise , Vinho/análise
11.
Food Chem ; 332: 127426, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32619948

RESUMO

A selected Pichia fermentans strain was simultaneously and sequentially inoculated in synthetic and real juice with S. cerevisiae strains of different antagonistic activities in a ratio 1:1 to observe the correlation between varietal odorants and glycosidase activities. Fermentations using pure S. cerevisiae strains were used for comparison. Yeast biomass and glycosidase activities were monitored, varietal odorants were detected using HS-SPME-GC/MS during fermentation. The final wine aroma attributes were analyzed by trained panelists. Results showed that co-inoculation with high antagonistic S. cerevisiae resulted in higher glycosidase activities than others. Pearson correlation analysis indicated that yeast biomass was positively related to glycosidase activities during fermentation. The increase in glycosidase activities was the main reason for the higher production of terpenes and C13-norisoprenoids, and for the lower C6 compound content, which lead to superior fruity and floral aromas in the final wine samples of the high antagonistic S. cerevisiae group.


Assuntos
Proteínas Fúngicas/metabolismo , Glicosídeo Hidrolases/metabolismo , Pichia/metabolismo , Saccharomyces cerevisiae/metabolismo , Vinho/análise , Fermentação , Frutas/química , Sucos de Frutas e Vegetais/análise , Sucos de Frutas e Vegetais/microbiologia , Cromatografia Gasosa-Espectrometria de Massas , Norisoprenoides/análise , Norisoprenoides/metabolismo , Odorantes/análise , Pichia/enzimologia , Pichia/crescimento & desenvolvimento , Terpenos/análise , Terpenos/metabolismo
12.
Food Chem ; 332: 127417, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32629332

RESUMO

The use of UHPH sterilization in the absence of SO2 has been used to eliminate wild microorganisms and inactivate oxidative enzymes. A white must of the Muscat of Alexandria grape variety was continuously processed by UHPH at 300 MPa (inlet temperature: 23-25 °C). The initial microbial load of the settled must was 4-log CFU/mL for both yeast and moulds, and slightly lower for bacteria. After UHPH processing, no microorganisms were detected in 1 mL. UHPH musts remain without fermentative activity for more than 60 days. Concentrations of the thermal markers indicated the absence of thermal damage in the UHPH-treated musts, since 5-hydroxymethylfurfural was not detected. In addition, the must treated by UHPH keeps terpene concentrations similar to those of the untreated controls. A strong inactivation of the oxidative enzymes was observed, with no browning at room temperature for more than 3 days. The antioxidant value of the UHPH-treated must was 156% higher than the control.


Assuntos
Bactérias/crescimento & desenvolvimento , Microbiologia de Alimentos/métodos , Fungos/crescimento & desenvolvimento , Esterilização/métodos , Vinho/análise , Bactérias/enzimologia , Bactérias/metabolismo , Fermentação , Manipulação de Alimentos , Fungos/enzimologia , Fungos/genética , Fungos/metabolismo , Humanos , Dióxido de Enxofre/análise , Paladar , Temperatura , Vitis/química
13.
Environ Sci Pollut Res Int ; 27(32): 40148-40155, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32661960

RESUMO

Enantioselective monitoring of chiral fungicide mandipropamid enantiomers were carried out in grapes and wine-making process. The enantiomers of mandipropamid were separated on a Lux Cellulose-2 column and determined by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The processing procedure included washing, fermentation, and clarification. Significant enantioselectivity was observed in grape under field conditions and during wine-making processing. The half-lives of R-mandipropamid and S-mandipropamid were 5.63 days and 7.79 days under field conditions 43.3 h and 69.3 h during wine-making processing, respectively. The EF values ranged from 0.498 to 0.283 in grape under field conditions, and the EF values were from 0.458 (0 h) to 0.362 (312 h) during the whole fermentation process. The results indicated that R-mandipropamid degraded faster than S-mandipropamid in grape under field conditions and during the fermentation process. The processing factors (PFs) were less than 1 for each procedure, and the PF ranged from 0.005 to 0.025 in the overall process, which indicated that the wine-making process can reduce mandipropamid residue in grape wine. The results of this study could help facilitate more accurate risk assessments of mandipropamid in table grapes and during wine-making process.


Assuntos
Vitis , Vinho , Amidas , Ácidos Carboxílicos , Cromatografia Líquida de Alta Pressão , Estereoisomerismo , Espectrometria de Massas em Tandem , Vinho/análise
14.
Food Chem ; 332: 127409, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32615388

RESUMO

This work reports a new method to evaluate the antioxidant capacity of infusions and beverages, based on superoxide radicals. Radicals produced by the enzymatic reaction between acetylcholinesterase and hypoxanthine oxidized antioxidant molecules present in commercially available samples or standard solutions, which was monitored by means of cyclic voltammetry using a carbon paste electrode. The Trolox equivalent antioxidant capacity (TEAC) of red wine, coffee and green tea determined using this method were: (1.20 ± 0.06), (0.90 ± 0.02), and (0.65 ± 0.02), respectively. This method suggested TEACred wine > TEACcoffee > TEACgreen tea, which is the same as DPPH, spectrophotometric method. However, the electrochemical one proposed here is rapid and simple.


Assuntos
Antioxidantes/química , Bebidas/análise , Técnicas Eletroquímicas/métodos , Superóxidos/química , Antioxidantes/metabolismo , Café/química , Eletrodos , Concentração de Íons de Hidrogênio , Hipoxantina/química , Hipoxantina/metabolismo , Oxirredução , Superóxidos/metabolismo , Chá/química , Vinho/análise , Xantina Oxidase/metabolismo
15.
Chemosphere ; 261: 127696, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32711239

RESUMO

The presence of fungicide and insecticide residues in wine has been largely investigated. However, few studies have addressed the persistence of these compounds in vineyard soils. In this research, we investigate the residues of a relevant number of fungicides and insecticides in vineyard soils, obtained in the Northwest of Spain, at the beginning of each agriculture campaign. Moreover, the dissipation of species showing high concentrations were monitored during the non-vegetative period of vines, in order to understand their soil evolution between application campaigns. To this end, a multiresidue analytical procedure based on pressurized liquid extraction (PLE) followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) determination was first optimized. Under final working conditions, absolute recoveries in the range from 70 to 130% were achieved for 44 out of 51 selected compounds. The method LOQs remained at the low ng g-1 level (0.2-13 ng g-1) with a linear response range up to 500 ng g-1. Analysis of vineyard soils, collected during a 2-year period, from a geographic area with a high incidence of fungal diseases, demonstrated the presence of relevant concentrations of several fungicides and the insecticide imidacloprid (IMI) in this compartment. Most compounds detected at the end of the application season remained in soil at the beginning of the next year campaign. Among them, six fungicides (dimethomorph, boscalid, myclobutanil, penconazole, pyraclostrobin and pyrimethanil) and IMI showed average dissipation efficiencies below 50%, so they pose a potential to accumulate in this kind of soils.


Assuntos
Fungicidas Industriais/análise , Inseticidas/análise , Resíduos de Praguicidas/análise , Poluentes do Solo/análise , Agricultura , Cromatografia Líquida , Monitoramento Ambiental , Fazendas , Neonicotinoides , Nitrocompostos , Solo/química , Espanha , Espectrometria de Massas em Tandem/métodos , Triazóis , Vinho/análise
16.
Int J Food Microbiol ; 329: 108651, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32512285

RESUMO

In Latin, 'pulcherrima' is a superlative form of an adjective that translates as beautiful. Apart from being 'the most beautiful' yeast, Metschnikowia pulcherrima has a remarkable potential in production of wines with lower ethanol content. The oenological performance of six M. pulcherrima strains was hereby tested in sequential cultures with Saccharomyces cerevisiae. The best-performing strain MP2 was further characterised in fermentations with different S. cerevisiae inoculation delays in both white grape juice and Chemically Defined Grape Juice Medium (CDGJM). The analysis of main metabolites, undertaken prior to sequential inoculations and upon fermentation completion, highlighted metabolic interactions and carbon sinks other than ethanol in MP2 treatments. Depending on the inoculation delay, MP2 white wines contained between 0.6% and 1.2% (v/v) less ethanol than the S. cerevisiae monoculture, with even larger decreases detected in the CDGJM. The MP2 treatments also contained higher concentrations of TCA cycle by-products (i.e. fumarate and succinate) and glycerol, and lower concentrations of acetic acid. The analysis of volatile compounds showed increased production of acetate esters and higher alcohols in all MP2 wines, alongside other compositional alterations arising from the S. cerevisiae inoculation delay.


Assuntos
Fermentação , Microbiologia de Alimentos/métodos , Metschnikowia/metabolismo , Saccharomyces cerevisiae/metabolismo , Vinho/microbiologia , Ácido Acético/metabolismo , Etanol/metabolismo , Glicerol/metabolismo , Fatores de Tempo , Vitis/metabolismo , Vitis/microbiologia , Vinho/análise
17.
Food Chem ; 329: 127085, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32512390

RESUMO

The refractive index is a basic optical property of materials. This study explores the effect of ethanol, glycerol, tartaric acid and glucose/fructose on the refractive index in model aqueous solutions and in dry white wines. Various model aqueous solutions consisting of these components were prepared and the refractive index was measured at 20 °C and each component was studied both alone and in mixtures with the others. The refractive index of white dry wines samples was also measured. A linear regression analysis was performed and linear multi-dependence equations were derived. The resulting regression models had a coefficient of determination over 97.3%. Glucose/fructose was found to have the greatest effect on the refractive index, followed by tartaric acid and glycerol while ethanol had the smallest effect. The knowledge of the correlation of the concentration of each wine component to the refractive index can be of value for the estimation of fermentation kinetics.


Assuntos
Etanol/química , Frutose/química , Glucose/química , Glicerol/química , Tartaratos/química , Água/química , Vinho/análise , Refratometria
18.
Food Chem ; 329: 127086, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32516706

RESUMO

Principal component analysis (PCA) and partial least squares (PLS) regression were applied to investigate the effect of glutathione-enriched inactive dry yeast (g-IDY) on the amino acids and volatile components of kiwi wine. Results indicated that the addition of g-IDY had positive effect on most amino acids of kiwi wine, especially glutamine and glycine. In case of pure juice fermentation, the concentrations of ethyl decanoate, 2-methylbutyric acid, trans-2-nonenal and hexyl butyrate had notably positive correlation with the addition of g-IDY. PLS regression indicated that the amino acids were highly interrelated to the volatile compositions, and glycine had the strongest positive impact on the concentrations of esters and total volatile components. This might explain the similar effect of g-IDY on the amino acids and volatile components of kiwi wine. Besides, PLS regression showed that E-nose was a good method to predict volatile compositions of kiwi wine, especially esters.


Assuntos
Actinidia/química , Aminoácidos/análise , Glutationa/metabolismo , Saccharomyces cerevisiae/química , Compostos Orgânicos Voláteis/análise , Vinho/análise , Actinidia/metabolismo , Nariz Eletrônico , Ésteres/análise , Fermentação , Análise Multivariada , Saccharomyces cerevisiae/metabolismo
19.
Food Chem ; 328: 127040, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32512467

RESUMO

Wine ageing in barrels is conditioned, among other factors, by the amount of oxygen received during this process, which thus impacts its final properties. The aim of this study was to evaluate the effect of oxygen on wine colour during ageing in barrels and bottles during different times. The use of barrels with different and known rates of oxygenation allows the effect of different oxygenation conditions throughout the process in barrels and its later evolution in bottles. A simulation process of ageing in bottles was used to study the impact of bottling in wines after differing ageing periods in barrels. The study of winés oxygen consumption capacity has been tied to colour modifications during ageing in barrels and bottles. Wines aged in barrels with a high oxygenation rate showed greater avidity to consume oxygen taking less time to consume that available, which is reflected in a greater increase in colour intensity.


Assuntos
Armazenamento de Alimentos/métodos , Oxigênio/química , Vinho/análise , Cor , Cinética , Fatores de Tempo
20.
Food Chem ; 329: 127181, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32502743

RESUMO

The compounds that the wood releases to the wine and the oxygen transmission rate (OTR) of the barrel define the final wine. The new possibility of choosing the OTR of the barrel allows the winemaker to globally control the ageing process. The aim of this work was to study the volatile composition of woods classified according to their OTR, which are used to build barrels for wine ageing. The results showed that volatile composition differs depending on wood OTR and the temperature reached during toasting. On the toasted side of the stave in contact with the wine, low OTR wood had a statistically higher content in furan compounds (5-hydroxymethylfurfural, furfural and 5-methylfurfural), acetovanillone and phenolic aldehydes (vanillin and syringaldehyde), while 4-ethylguaiacol and trans-ß-methyl-γ-octalactone were significantly higher in staves with a high OTR. The same red wine aged first for three months in high and low oxygenation barrels presents different characteristics.


Assuntos
Manipulação de Alimentos/métodos , Oxigênio/química , Quercus/química , Compostos Orgânicos Voláteis/química , Vinho/análise , Benzaldeídos/química , Cromatografia Gasosa , Análise Discriminante , Furanos/química , Guaiacol/química , Temperatura , Madeira/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA