Cláudia Zini - Profile on Academia.edu (original) (raw)

Papers by Cláudia Zini

Role of partial dehydration in a naturally ventilated room on the mycobiota, ochratoxins, volatile profile and phenolic composition of Merlot grapes intended for wine production

Food Research International, Mar 1, 2021

Dehydration of grapes has been used in various regions of the world to produce special wines, aim... more Dehydration of grapes has been used in various regions of the world to produce special wines, aiming to add value to oenological products. Post-harvest dehydration in rooms may be carried out regardless of weather conditions, without the additional cost of a specific infrastructure, in addition to the benefits of protecting the grapes from damages and environmental pollution. The objective of this study was to verify, for the first time, the impact of the dehydration in a naturally ventilated room on the quality of Merlot grapes. Physicochemical characteristics, mycobiota, occurrence of mycotoxins, volatile profile and phenolic composition of grapes were monitored on 7th, 14th and 21st days of dehydration (weight loss of 10, 20 and 27%, respectively). A decrease in aw (6%), pH (4%), and berry hardness (58%), along with an increase in total soluble solid content (15%) were observed during dehydration. The presence of Pestalotiopsis clavispora, Neopestalotiopsis clavispora, Colletotrichum siamense and Alternaria porri was favored during the dehydration process, while a decrease in the occurrence of Aspergillus niger and Phanerochaete sp. was verified. A. niger isolates showed no potential to produce forms of ochratoxins. These toxins were also not found in the grape samples. Regarding the volatile profile, 1-hexanal, 2-hexenal, and 1-octanal gave rise to the corresponding alcohols during dehydration, such as 1-hexanol, 2-hexen-1-ol, and 1-octanol. Acids (hexanoic, decanoic, and 3-hexenoic) resulted in the respective ethyl esters (hexanoate, decanoate, and ethyl 3-hexenoate) during dehydration. Terpenes as limonene, myrcene, and geraniol decreased throughout dehydration, while their biotransformation products (α-terpineol, 6-methyl-5-hepten-2-one, and linalool, respectively) had an increase in concentration. The phenolic content oscillated during dehydration, with an emphasis on increased levels of four hydroxybenzoic acids (ethyl gallate, p-hydroxybenzoic acid, gallic acid-hexose, and gallic acid), two hydroxycinnamic acids (caffeic acid and caftaric acid), two flavonols (kaempeferol galactoside and quercetin) and two anthocyanins (peonidin 3-O-hexoside and delphinidin 3-O-hexoside). Grapes of satisfactory quality were produced by dehydration in a naturally ventilated room. Even small wine producers can be encouraged to implement this procedure for the diversification of oenological products, as it has no costs related to the implementation of chambers/tunnels.

GC×GC/qMS in the analysis of bio-oils from pyrolysis of biomass

Journal of Fundamentals of Renewable Energy and Applications, Sep 28, 2016

Compostos fenolicos clorados em efluente de fabrica kraft de celulose utilizando 80% de substituicao por dioxido de cloro no estagio dc

O papel, 1994

Food Additives & Contaminants: Part A, Oct 17, 2019

Carbonyl compounds and furan derivatives may form adducts with DNA and cause oxidative stress to ... more Carbonyl compounds and furan derivatives may form adducts with DNA and cause oxidative stress to human cells, which establishes the carcinogenic potential of these compounds. The occurrence of these compounds may vary according to the processing characteristics of the beer. The objective of this study was, for the first time, to investigate the free forms of target carbonyl compounds [acetaldehyde, acrolein, ethyl carbamate (EC) and formaldehyde] and furan derivatives [furfural and furfuryl alcohol (FA)] during the brewing stages of ale and lager craft beers. Samples were evaluated using headspacesolid phase microextraction and gas chromatography with mass spectrometric detection in selected ion monitoring mode (HS-SPME-GC/MS-SIM). Acetaldehyde, acrolein, formaldehyde and furfuryl alcohol were found in all brewing stages of both beer types, while EC and furfural concentrations were below the LOD and LOQ of the method (0.1 and 0.01 µg L -1 , respectively). Boiling and fermentation of ale brewing seem to be important steps for the formation of acrolein and acetaldehyde, respectively, while boiling resulted in an increase of FA in both types of beer. Conversely, pasteurisation and maturation reduced the levels of these compounds in both types of beer. An increase in concentration of acrolein has not been verified in lager brew probably due to the difference in boiling time between these two types of beer (60 and 90 min for ale and lager, respectively).

Volatile and sensory profile of sparkling wines produced by faster and alternative methods (Ancestral and Single Tank Fermentation) compared to the usual methods (Charmat and Traditional)

European Food Research and Technology, Jun 15, 2023

Phenolic compounds are one of the major quality factors in grapes, and therefore in the resulting... more Phenolic compounds are one of the major quality factors in grapes, and therefore in the resulting wine. Many factors may influence the phenolic composition of wine, such as variety, edaphoclimatic conditions and cultural practices. One of these factors is the maturity degree of the grapes used, once the wine prepared from grapes harvested before optimum phenolic maturity shows a lower content of anthocyanins and a higher content of tannins from the seeds, which grants the beverage an elevated astringency and a sensation of "dryness" upon its ingestion. In this context, the present work aimed to study the phenolic content, physical-chemical composition and antioxidant activity of red wines cv Syrah prepared from grapes harvested at different stages of ripeness.

Food Research International, Dec 1, 2019

Aspergillus carbonarius can produce a possibly carcinogenic mycotoxin named ochratoxin A (OTA). T... more Aspergillus carbonarius can produce a possibly carcinogenic mycotoxin named ochratoxin A (OTA). The metabolism of this fungus can also impact grape and wine quality as it influences the volatile and phenolic profiles, which are related to aroma and antioxidant activity, respectively. The objective of this study was to evaluate the effect of A. carbonarius on OTA levels and for the first time on volatile profile and antioxidant activity of grapes and their respective wines. Cabernet Sauvignon (CS, red) grapes presented higher susceptibility to A. carbonarius than Moscato Italico (MI, white) grapes and OTA levels in their respective musts were in accordance with this same trend. However, vinification of red grapes resulted in 67% reduction of OTA, while the reduction observed with white wines was 45%. The presence of acids (hexanoic, octanoic, nonanoic and decanoic, fatty odor) was found to be an indicative of the fungus incidence in grapes. These acids were precursors of esters that might impart negative aroma (methyl nonanoate and isoamyl octanoate, fatty odor) or provide desirable fruity characteristics (ethyl hexanoate, ethyl octanoate and methyl octanoate) for wine. In addition, terpenes were detected only in wines produced with grapes (CS and MI) inoculated with A. carbonarius. The presence of A. carbonarius increased the antioxidant activity of CS grapes. For MI grapes and both wines (CS and MI) no differences were verified in the antioxidant activity of the samples affected or not affected by this fungus. Although A. carbonarius occurrence has shown no influence on the antioxidant activity of wines, it produced OTA and has negatively influenced the wine odor profile, due to the production of some volatiles that impart a deleterious effect on wine aroma.

Analytical Chemistry, Sep 29, 2016

As columns age and differ between systems, retention times for comprehensive two-dimensional gas ... more As columns age and differ between systems, retention times for comprehensive two-dimensional gas chromatography (GCxGC) may vary between runs. To properly analyze GCxGC chromatograms, it often is desirable to align the retention times of chromatographic features, such as analyte peaks, between chromatograms. Previous work by the authors has shown that global, low-degree polynomial transformation functions, namely affine, second-degree polynomial, and third-degree polynomial, are effective for aligning pairs of two-dimensional chromatograms acquired with dual second columns and detectors (GC×2GC). This work assesses the experimental performance of these global methods on more general GCxGC chromatogram pairs and compares their performance to that of a recent, robust, local alignment algorithm for GCxGC data [Gros et al. Anal. Chem. 2012, 84, 9033]. Measuring performance with the root-mean-square (RMS) residual differences in retention times for matched peaks suggests that global, low-degree polynomial transformations outperform the local algorithm given a sufficiently large set of alignment points, and are able to improve misalignment by over 95% based on a lower-bound benchmark of inherent variability. However, with small sets of alignment points, the local method demonstrated lower error rates (although with greater computational overhead). For GCxGC chromatogram pairs with only slight initial misalignment, none of the global or local methods performed well. In some cases with initial misalignment near the inherent variability of the system, these methods worsened alignment, suggesting that it may be better not to perform alignment in such cases.

O Brasil é um grande fabricante de celulose de eucalipto e experimentou progressos importantes na... more O Brasil é um grande fabricante de celulose de eucalipto e experimentou progressos importantes na gestão ambiental nesta área nas últimas décadas. Entretanto, ainda há oportunidades para usos alternativos dos resíduos dessas fábricas, que podem resultar em produtos de maior valor agregado. As caracterizações qualitativa e semi-quantitativa da composição do bio-óleo de pirólise de três resíduos da indústria celulose (serragem de eucalipto, resíduo do digestor e lodo) foram realizadas utilizando-se cromatografia gasosa bidimensional abrangente com detector por espectrometria de massas por tempo de voo (GC×GC/TOF-MS). As melhores condições de pirólise para o resíduo do digestor foram aplicadas aos demais resíduos, obtendo-se bio-óleos complexos, sendo os bio-óleos do resíduo do digestor e da serragem qualitativamente semelhantes e o do lodo, um pirolisado de maior complexidade. As vantagens da técnica GC×GC/TOF-MS para esta aplicação específica são apresentadas, bem como o potencial dos componentes dos bio-óleos (fenóis e cetonas) para aplicações industriais importantes. Brazil is a great manufacturer of Eucalyptus pulp and has experienced important improvements in the environmental management in the last decades. However, there are still opportunities for alternative uses of pulp mill residues, which may result in higher added value products. Qualitative and semi-quantitative characterizations of bio-oil composition of three pulp mill residues (Eucalyptus sawdust, digester residue and wastewater treatment sludge) were performed using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection (GC×GC/TOF-MS). The best pyrolysis conditions achieved for the digester residue were applied to the other residues and similar bio-oils were obtained for sawdust and digester residue, while sludge rendered a more complex pyrolysate. The advantages of GC×GC/TOF-MS for this specific application are presented, as well as the potential of bio-oil components for important industrial applications.

O Papel: revista mensal de tecnologia em celulose e papel, 2012

Palavras-chave: biomassa, bio-óleo, cromatografia gasosa, pirólise Resumo a indústria de celulose... more Palavras-chave: biomassa, bio-óleo, cromatografia gasosa, pirólise Resumo a indústria de celulose e papel no brasil apresenta alta eficiência ambiental, com sua performance comparada ao que existe de melhor no mundo em termos de gerenciamento ambiental. entretanto, o uso de alguns resíduos desse setor para fins mais nobres abre perspectivas para um gerenciamento ambiental ainda melhor. neste trabalho a serragem, o resíduo do digestor e o lodo da estação de tratamento de efluentes -resultantes do processo de fabricação de celulose de eucalipto -foram submetidos a pirólise rápida para investigação de uma rota processual alternativa que agregue valor a esses materiais. foi desenvolvido um planejamento experimental para a biomassa do digestor em que a massa de resíduo (3, 5 e 7 g) e a temperatura final de pirólise (350, 450 e 550ºC) foram variadas, enquanto a taxa de aquecimento (100ºC/min) e o fluxo de nitrogênio (1 ml/min) foram mantidos constantes. a melhor condição experimental foi a de 7 g de biomassa e temperatura de 550ºC, levando-se em conta o maior rendimento de bio-óleo e o percentual de siringol, que é o seu composto majoritário. o emprego de uma menor granulometria (20 mesh) dos resíduos e de um condensador mais longo para os voláteis resultaram em maior rendimento em bio-óleo. os gases condensáveis e não condensáveis deste processo foram analisados por cromatografia gasosa acoplada a detector de espectrometria de massas (gC/ms), bem como por cromatografia gasosa bidimensional abrangente acoplada a detector de espectrometria de massas por tempo de voo (gC×gC/tofms). Compostos como fenóis, hidrocarbonetos, ácidos carboxílicos, aldeídos e cetonas foram encontrados no bio-óleo, havendo perspectiva de utilização de frações deste bio--óleo para produção de produtos químicos de maior valor agregado ou para uso como combustítvel. *Authors' references: 1. universidade federal do rio grande do sul -ufrgs. av. bento gonçalves, 9500 -porto alegre -rs -brasil 2. ecoáguas, engenharia do meio ambiente. r. dr. lauro azambuja, 118, s. 706 -guaíba -rs -brasil

Food Additives & Contaminants: Part A, Oct 9, 2019

Compounds with toxic potential may occur in beer, such as carbonyl compounds (acetaldehyde, acrol... more Compounds with toxic potential may occur in beer, such as carbonyl compounds (acetaldehyde, acrolein, ethyl carbamate [EC] and formaldehyde) and furan derivatives [furfural and furfuryl alcohol (FA)]. The objective of this study was, for the first time, to validate a method based on headspace-solid phase microextraction using a PDMS-overcoated fibre and gas chromatography with mass spectrometric detection in selected ion monitoring mode (HS-SPME-GC/MS-SIM) to investigate target carbonyl compounds and furan derivatives in beers. Analytical curves showed proper linearity with r 2 ranging from 0.9731 to 0.9960 for acetaldehyde and EC, respectively. The lowest LOD was found for acetaldehyde (0.03 µg L -1 ), while the lowest LOQ value (1.0 µg L -1 ) was found for acetaldehyde and EC, formaldehyde and furfural. Recovery (90% to 105%), intermediate precision and repeatability (lower than 13%), limits of detection and quantification (values below 2.5 μg L -1 ) showed that the method is suitable to simultaneously quantify these compounds. EC was detected in only two samples (1 lager and 1 ale). Furfural was found in 37% and 82% of ale and lager beers, respectively. Acetaldehyde, acrolein, formaldehyde and FA were detected in all samples. However, acrolein was the only compound found in the commercial samples at a concentration capable of causing health risk. Besides furfural and FA, four other furan-containing compounds (5-methyl-2-furan methanethiol, acetylfuran, 5-methylfurfural and γ-nonalactone) were also found in beers, however, at levels low enough not to impose potential health risk.

Holzforschung, Feb 29, 2000

Bench filtrates from three-stage conventional bleaching sequences (CEoD) with substitution degree... more Bench filtrates from three-stage conventional bleaching sequences (CEoD) with substitution degrees of chlorine by chlorine dioxide in the first stage equals to zero, 25 %, 75 % and 100 % have been analysed for their content of chlorinated phenolic compounds (CPCs). Alternatively, CPCs filtrates content of an AZEoPD sequence were also determined. A cellulose pulp obtained from a mixture of 85 % Eucalyptus saligna (young trees) and 15 % Acacia mearnsii delignified with oxygen (kappa number 10.0) was employed in all bleaching tests. Levels of CPCs were determined by using an in situ acetylation method followed by GC/ECD technique. GC/MS of bleaching filtrates was employed in qualitative analyses. CPCs content in filtrates and the Kovacs' equivalent toxicity for the total filtrates of the studied bleaching sequences are presented. The lowest content of CPCs was found in AZEoPD filtrates, as expected due to the utilised bleaching agents. CPCs were not detected in the filtrates of stage D from the AZEoPD sequence probably due to the low lignin content of the pulp. Mixed filtrates of the sequence DEoD, showed the lowest CPCs content among conventional bleachings. Results are in accordance with those found in the literature for hardwood and softwood pulp. The equivalent toxicity in the sequences Dc(75/25), DEoD and AZEoPD was found to be lower than the limit given by Kovacs to characterise chronical toxicity.

Química Nova, 2011

Recebido em 27/9/10; aceito em 16/1/11; publicado na web em 29/3/11 APPLICATION OF COMPREHENSIVE ... more Recebido em 27/9/10; aceito em 16/1/11; publicado na web em 29/3/11 APPLICATION OF COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY WITH MICRO-ELECTRON CAPTURE DETECTION FOR DETERMINATION OF PESTICIDES IN SEDIMENTS. Analysis of seven pesticides in sediments was successfully achieved using comprehensive two-dimensional gas chromatography with micro-electron capture detection, as it provided higher sensitivity and less matrix interference. Repeatability and intermediate precision of peak areas and heights were less than 4% and the recovery percentage for the analytes ranged from 52 to 115%. Instrumental LOD and LOQ were in the range of 0.60 to 2.31 mg L -1 and 1.83 to 5.62 mg L -1 , respectively. Concentrations of 3.34 mg kg -1 (dry basis) for trifloxystrobin and azoxystrobin (below the LOQ) were found in a sediment sample.

Journal of the Brazilian Chemical Society, 2018

Heat map and hierarchical cluster analysis showed that sparkling wines produced with immobilized ... more Heat map and hierarchical cluster analysis showed that sparkling wines produced with immobilized yeasts contained mostly higher levels of compounds that impart positive notes to wines. Fisher ratio pointed out nine volatile compounds as the main components responsible for differentiation of samples treated with mannoproteins/lees and others. Principal component analysis (PCA) showed differences between the sparkling wines produced with and without adjuvants (commercial mannoproteins or lees). Sparkling wines aged without adjuvants presented higher levels of decanoic and dodecanoic acids (fatty/metallic aroma), while the use of mannoproteins or lees resulted in higher content of some fruity esters, nerolidol and β-damascenone. Therefore, the combination of immobilized yeast and aging on mannoproteins or lees seems to be the most promising treatment to obtain the volatile profile that positively influence wine quality.

Benchmarking machine learning methods for comprehensive chemical fingerprinting and pattern recognition

Journal of Chromatography A, Jun 1, 2019

Machine learning (ML) has been used previously to recognize particular patterns of constituent co... more Machine learning (ML) has been used previously to recognize particular patterns of constituent compounds. Here, ML is used with comprehensive chemical fingerprints that capture the distribution of all constituent compounds to flexibly perform various pattern recognition tasks. Such pattern recognition requires a sequence of chemical analysis, data analysis, and pattern analysis. Chemical analysis with comprehensive multidimensional chromatography is a maturing approach for highly effective separations of complex samples and so provides a solid foundation for undertaking comprehensive chemical fingerprinting. Data analysis with smart templates employs marker peaks and chemical logic for chromatographic alignment and peak-regions to delineate chromatographic windows in which analytes are quantified and matched consistently across chromatograms to create chemical profiles that serve as complete fingerprints. Pattern analysis uses ML techniques with the resulting fingerprints to recognize sample characteristics, e.g., for classification. Our experiments evaluated the effectiveness of seventeen different ML techniques for various classification problems with chemical fingerprints from a rich data set from 126 wine samples of different varieties, geographic regions, vintages, and wineries. Results of these experiments showed an accuracy range from 58% to 88% for different ML methods on the most difficult classification problems and 96% to 100% for different ML methods on the least difficult classification problems. Averaged over 14 classification problems, accuracy for the different methods ranged from 80% to 90%, with some relatively simple ML techniques among the top-performing methods.

Journal of the Brazilian Chemical Society, 2013

Food Additives & Contaminants: Part A, Nov 14, 2018

The objective of this research was to estimate for the first time the transformations that the fr... more The objective of this research was to estimate for the first time the transformations that the free form of some target carbonyl compounds may undergo during winemaking and assess the exposure risk to these compounds through the consumption of the Merlot commercial wines under study. Acrolein and furfural were found in grapes and the respective wines, although levels were observed to decline throughout the winemaking process. Formaldehyde was found in all stages of wine production in levels lower than the limit of quantification of the method and ethyl carbamate was not found in samples. Acetaldehyde seems to be a precursor of acetoin and 2,3-butanediol, since the levels of this aldehyde decreased along winemaking and the formation of the ester and alcohol was verified. Furfural levels decreased, while the occurrence of furan-containing compounds increased during winemaking. The formation of acetaldehyde during alcoholic fermentation and the potential environmental contamination of grapes with acrolein and furfural are considered as the critical points related to the presence of toxic carbonyl compounds in the wine. Acrolein was found in the samples under study in sufficient quantities to present risk to human health, while other potentially toxic carbonyl compounds did not result in risk. This study indicated for the first time the presence of acrolein in grapes suggesting that environmental pollution can play an important role in the levels of this aldehyde detected in wines. Reduction of the emission of this aldehyde to the environment may be achieved by replacing wood burning by another heat source in fireplaces or wood stones, and abandoning the practice of burning garbage and vegetation.

Slovak Tokaj wines classification with respect to geographical origin by means of one class approaches

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Aug 1, 2021

Tokaj wines could be produced only in so called Tokaj/Tokay wine region that falls within two cou... more Tokaj wines could be produced only in so called Tokaj/Tokay wine region that falls within two countries Slovakia and Hungary. Thus, wines bearing Tokaj appellation must be produced only in Hungary and Slovakia by traditional process. Unfortunately, some counterfeit wines from neighbour region in Ukraine could be found in market. The aim of this work is to explore a simple UV-VIS spectrum to recognise true Tokaj/Tokay wines from counterfeits and try to differentiate wines based on their country of origin. This type of question can be duly answered using one class classification approach. Two different approaches, Data Driven Soft Independent Modelling of Class Analogy - DD-SIMCA and One-Class Partial Least Squares - OC-PLS were tested and evaluated for this purpose. In both cases, rigorous way models were built and optimized using only samples of the target class. A set of external samples containing samples from target class and non-target were used to validate the models ability to recognize Slovak samples and reject non-Slovak samples. Model based on DD-SIMCA showed better performance (97% correct rating) compared to OC-PLS models (80% correct rating). Comparing both approaches in terms of sensitivity and specificity, both exhibit high sensitivity (low false negative rate: DD-SIMCA 95% and OC-PLS 100%), however the OC-PLS based model showed low specificity (40%) while DD-SIMCA showed high specificity (100%) rejecting all samples out of Slovak origin. Therefore, the results found in this study show that it is possible to successfully combine UV-VIS spectra and DD-SIMCA models to discriminate Tokaj wine samples of Slovak origin from others. Equally important is environmentally friendly (fast, simple, absence of solvents) classification method in line with green chemistry.

ChemInform Abstract: A Selective Reduction of α,β-Unsaturated Ketones

ChemInform, Aug 19, 2010