Vitor Manfroi

Characterization of the volatile profile of Brazilian Merlot wines through comprehensive two dimensional gas chromatography time-of-flight mass spectrometric detection.

Wine aroma is an important characteristic and may be related to certain specific parameters, such as raw material and production process. The complexity of Merlot wine aroma was considered suitable for comprehensive two-dimensional gas chromatography (GC×GC), as this technique offers superior performance when compared to one-dimensional gas chromatography (1D-GC). The profile of volatile compounds of Merlot wine was, for the first time, qualitatively analyzed by HS-SPME-GC×GC with a time-of-flight mass spectrometric detector (TOFMS), resulting in 179 compounds tentatively identified by comparison of experimental GC×GC retention indices and mass spectra with literature 1D-GC data and 155 compounds tentatively identified only by mass spectra comparison. A set of GC×GC experimental retention indices was also, for the first time, presented for a specific inverse set of columns. Esters were present in higher number (94), followed by alcohols (80), ketones (29), acids (29), aldehydes (23), terpenes (23), lactones (16), furans (14), sulfur compounds (9), phenols (7), pyrroles (5), C13-norisoprenoids (3), and pyrans (2). GC×GC/TOFMS parameters were improved and optimal conditions were: a polar (polyethylene glycol)/medium polar (50% phenyl 50% dimethyl arylene siloxane) column set, oven temperature offset of 10 °C, 7s as modulation period and 1.4s of hot pulse duration. Co-elutions came up to 138 compounds in 1D and some of them were resolved in 2D. Among the co-eluted compounds, thirty-three volatiles co-eluted in both 1D and 2D and their tentative identification was possible only due to spectral deconvolution. Some compounds that might have important contribution to aroma notes were included in these superimposed peaks. Structurally organized distribution of compounds in the 2D space was observed for esters, aldehydes and ketones, alcohols, thiols, lactones, acids and also inside subgroups, as occurred with esters and alcohols. The Fischer Ratio was useful for establishing the analytes responsible for the main differences between Merlot and non-Merlot wines. Differentiation among Merlot wines and wines of other grape varieties were mainly perceived through the following components: ethyl dodecanoate, 1-hexanol, ethyl nonanoate, ethyl hexanoate, ethyl decanoate, dehydro-2-methyl-3(2H)thiophenone, 3-methyl butanoic acid, ethyl tetradecanoate, methyl octanoate, 1,4 butanediol, and 6-methyloctan-1-ol.

Differentiation of wines according to grape variety using multivariate analysis of comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection data

Headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC×GC/TOFMS) was used to analyse the volatiles in five types of wines elaborated with grapes of Cabernet Sauvignon, Merlot, Chardonnay, Sauvignon Blanc and Pinot Noir varieties. Fisher ratio, principal component analysis (PCA) and stepwise linear discriminant analysis (SLDA) were used to develop a discriminant model and, as a result, 12 volatile compounds enabled differentiation and classification of wines according to grape cultivars. A detailed examination of GC×GC/TOFMS data showed that the use of one-dimensional gas chromatography with a mass spectrometric detector (1D-GC/MS) would probably result in misidentification of some of these 12 compounds, as they showed partial coelution with other components in the first chromatographic dimension.

Detection of the origin of Brazilian wines based on the determination of only four elements using high-resolution continuum source flame AAS.

A method has been developed to determine 10 elements in Brazilian red wines using high-resolution continuum source flame atomic absorption spectrometry, a technique that allows the fast sequential determination of an essentially unlimited number of elements per sample, each one under previously optimized conditions. All measurements were made without sample preparation, using aqueous standard solutions for calibration. The results were in agreement within 99% of confidence (t-test) with those obtained by inductively coupled plasma optical emission spectrometry. The same grape, Cabernet sauvignon, was used in all experiments, and the wines from each region were prepared especially for this investigation in order to avoid any confusion due to grapes from other regions, which are often used in commercial wines. The elements K, Mn, Rb and Sr were found to be the best indicators for the origin of the wines, based on a Principal Component Analysis.

Monitoring the evolution of volatile compounds using gas chromatography during the stages of production of Moscatel sparkling wine

This study reports, for the first time, the main changes that occur with some important aroma compounds of Moscatel sparkling wines during winemaking, measured using headspace solid-phase microextraction, one-dimensional and comprehensive two-dimensional gas chromatography (GC×GC) with mass spectrometry detection (MS). The best conditions of volatile extraction included the use of PDMS/DVB fibre, 2mL of wine, 30% of NaCl, 40°C for 30min. The chromatographic profile of sparkling wines showed decreasing amounts of monoterpenes (limonene, 4-terpineol, terpinolene, citronellol, α-terpineol, linalool, hotrienol, and nerol oxide), increasing amounts of esters (terpenyl esters, ethyl octanoate, ethyl decanoate and hexyl acetate) and alcohols (1-nonanol and 2-phenylethanol). Sixty-nine compounds co-eluted in the first dimension; only six co-eluted in the second dimension. GC×GC/TOFMS allows more detailed study of the volatile profile of sparkling wines.

Determination of ochratoxin A in wine from the southern region of Brazil by thin layer chromatography with a charge-coupled detector.

The presence of ochratoxin A (OTA) is evaluated using thin layer chromatography (TLC) with a charge-coupled detector (CCD) in 88 red wine samples (2009 vintage) from Brazil. Samples included 75 wines from Rio Grande do Sul, nine from Santa Catarina and four from Paraná state; 56 wines were Cabernet Sauvignon and 32 were Merlot varieties. The method included the analysis of fluorescent images, acquired under UV light, using ImageJ software. Mean recovery of OTA was 82.3% using immunoaffinity columns (IAC). The limits of quantification (LOQ) and detection (LOD) were 0.8 and 0.2 µg l−1, respectively. Results showed a 5.7% contamination of OTA, with five positive samples – three Cabernet Sauvignon and two Merlot. Santa Catarina and Paraná showed one positive sample each, although the concentrations were below the limit of quantification. The highest concentration found was 0.84 µg l−1 in one sample from Rio Grande do Sul.

The Use of Ozone in a CIP System in the Wine Industry

This study tested the efficacy of ozone in a CIP system of a wine industry, for that, a hose that transported wine was submitted to the following treatments: ozonated water at 28 ± 1 °C (in concentrations of 0.38 and 1.03 ppm for one, five and nine minutes); hot water (85 ± 1 °C for 15 minutes); peracetic acid (0.3% for 15 minutes); and a caustic soda solution (2%) with peracetic acid (0.3% for 15 minutes). The results indicate that the use of ozonated water is more effective than the isolated use of peracetic acid and the combined use of soda and peracetic acid.

Efeito do AIB sobre o enraizamento e desenvolvimento de estacas de quivi (Actinidia deliciosa)

The objective of this experiment was to study the effect of the 3-indolbutiric acid (IBA) on the rooting and development of semi-hardwood cuttings of kiwi, cv. Monty. The experiment was carried out at the Staccatos Experimental Agronomical/UFRGS in Eldorado do Soul. RS, Brazil with five treatments and five repetitions, in completely randomized blocks design. There were 19 bags per pilot with two cuttings per plastic bag grow in a catty: sane manure mixture (1:1:1) and treated by /BA at the concentrations of 2000ppm, 4000ppm, 6000ppm and 8000ppm. In addition to the contrail. IBA did not affect the rooting percentage but resulted in a linear increase of the mean root dry weight. Shoot development was not affected by the IBA. Buy there was a tendency for a linear increase of shoot length and dry weight in response to IBA concentrations above 2000 ppm.

Characterization of the Volatile Profile of Brazilian Moscatel Sparkling Wines Through Solid Phase Microextraction and Gas Chromatography

Solid phase microextraction, one-dimensional gas chromatography (1D-GC) and comprehensive two-dimensional gas chromatography (GC×GC) with mass spectrometric detector have been used to characterize the volatile profile of Moscatel sparkling wines. Predominant classes were esters, acids, alcohols and terpenes. The efficiency of GC×GC was apparent due to the higher number of compounds positively and/or tentatively identified through this technique (two and a half times higher than with 1D-GC), as well as by the separation of co-eluted compounds in 1D-GC. Principal components analysis showed that the volatile profile of the majority of sparkling wines is similar. Only two samples differed from others and the compounds responsible for this behavior were nerol, menthol, linalool acetate, limonene and geraniol. Furthermore, a clear separation among sparkling wines done with two Moscato grape varieties (Bianco and Giallo) was observed in cluster analysis due to the higher chromatographic area of terpenes and norisoprenoids verified in Giallo samples.

Ocratoxina A: análise da qualidade de vinhos brasileiros e importados

Estudos em diferentes partes do mundo mostraram que o vinho pode conter Ocratoxina A, uma micotoxina com propriedades nefrotoxicas e carcinogenicas. O objetivo deste trabalho foi avaliar a presenca de Ocratoxina A em vinhos brasileiros e importados, utilizando-se a tecnica de cromatografia em camada delgada com detector de carga acoplada. Foram analisadas 63 amostras de vinhos tintos brasileiros, argentinos, uruguaios e chilenos. O metodo se mostrou suficientemente sensivel para analise da micotoxina em vinho, com recuperacao de 99%. Os limites de deteccao e quantificacao foram 0,2 e 0,4 µg.L - 1, respectivamente. Nao foi constatada a presenca de Ocratoxina A em nenhuma das 63 amostras analisadas. A baixa ocorrencia dessa micotoxina registrada neste estudo esta de acordo com trabalhos semelhantes ja realizados e contribui, de certa forma, para a comprovada qualidade do vinho, produzido principalmente no sul do Brasil, alem de garantir a saude da populacao consumidora desses produtos.

Influência de taninos enológicos em diferentes dosagens e épocas distintas de aplicação nas características físico-químicas do vinho Cabernet Sauvignon

This study was carried out in the city of Bento Goncalves, RS, Brazil, with Cabernet Sauvignon, a cultivar known throughout the country for the production of cellaring red wine. Like with other red vines, there may be obstacles to maturation in certain harvests, which can make the production of well-structured wines difficult Among the strategies adopted to minimize this problem, is an adequate handling of the vineyard and certain enological operations. In this context, the objective of this study is to investigate the application of enological tannins in the physicochemical composition of the Cabernet Sauvignon wine. In the 2004 harvest, quebracho and chestnut tannins were applied in three different dosages (5,0, 10,0, 20,0 g.hl-1), and three different times of application (maceration, 2 days after crushing; drawing off,, 8 days after crushing; and after the malolatic fermentation, 4 months after crushing). In the stabilized wines, classic physicochemical analyses were performed and chromatic characteristics and polifenols were identified. Due to the good weather during this season, in terms of classic physicochemical characteristics, in general, it seems that the addition of tannins had little influence on the composition of the wine. The variables that would, hypothetically, be more influential, such as anthocyanins and color index, also showed few significant changes, whereas the R 280 and the levels of total tannins were affected.