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1.
Insect Sci ; 27(2): 256-265, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30047567

RESUMO

We tested the recent hypothesis that the "fly factor" phenomenon (food currently or previously fed on by flies attracts more flies than the same type of food kept inaccessible to flies) is mediated by bacterial symbionts deposited with feces or regurgitated by feeding flies. We allowed laboratory-reared black blow flies, Phormia regina (Meigen), to feed and defecate on bacterial Luria-Bertani medium solidified with agar, and isolated seven morphologically distinct bacterial colonies. We identified these using matrix-assisted laser desorption/ionization mass spectrometry and sequencing of the 16S rRNA gene. In two-choice laboratory experiments, traps baited with cultures of Proteus mirabilis Hauser, Morganella morganii subsp. sibonii Jensen, or Serratia marcescens Bizio, captured significantly more flies than corresponding control jars baited with tryptic soy agar only. A mixture of seven bacterial strains as a trap bait was more attractive to flies than a single bacterial isolate (M. m. sibonii). In a field experiment, traps baited with agar cultures of P. mirabilis and M. m. sibonii in combination captured significantly more flies than traps baited with either bacterial isolate alone or the agar control. As evident by gas chromatography-mass spectrometry, the odor profiles of bacterial isolates differ, which may explain the additive effect of bacteria to the attractiveness of bacterial trap baits. As "generalist bacteria," P. mirabilis and M. m. sibonii growing on animal protein (beef liver) or plant protein (tofu) are similarly effective in attracting flies. Bacteria-derived airborne semiochemicals appear to mediate foraging by flies and to inform their feeding and oviposition decisions.


Assuntos
Dípteros/microbiologia , Animais , Comportamento Apetitivo , Comportamento Alimentar , Feminino , Masculino , Odorantes/análise , Simbiose
2.
J Agric Food Chem ; 68(1): 258-266, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31825219

RESUMO

Screening the volatiles of cempedak [Artocarpus integer (Thunb.) Merr.] pulp for odor-active compounds by aroma extract dilution analysis and gas chromatography (GC)-olfactometry of static headspace samples revealed a total of 55 odorants, among which 47 were identified. Using stable isotopically substituted odorants as internal standards, these compounds were quantitated by GC-mass spectrometry, and odor activity values (OAVs) were calculated as ratios of the natural concentrations in cempedak pulp to the orthonasal odor detection thresholds. An aroma reconstitution model based on the 41 compounds with OAVs >1 in their natural concentrations successfully mimicked the characteristic aroma of cempedak pulp including the pronounced sulfury, oniony note which is intense in cempedak pulp but absent in jackfruit pulp. Further sensory tests finally showed that 2-(methylsulfanyl)propane, 2-(methylsulfanyl)butane, and 2-(methylsulfanyl)pentane are the key compounds responsible for this unique aroma note in cempedak pulp and vitally contribute to the aroma difference between cempedak pulp and jackfruit pulp.


Assuntos
Artocarpus/química , Odorantes/análise , Compostos Orgânicos Voláteis/química , Aromatizantes/química , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Estrutura Molecular , Olfatometria , Olfato
3.
J Agric Food Chem ; 68(1): 279-291, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31802659

RESUMO

This study aimed to identify the key aroma-active volatiles in cranberry wines through three vinification methods (White, Red and Thermo) using GC-MS/O to identify the important aroma compounds. A total of 70 compounds were detected, with 67 in wines and 61 in juices. The esters was the most diversified class, while alcohols and acids were the most abundant, especially 3-methylbutanol, methylbutyric acid, and benzoic acid. The volatile profiles of cranberry wines are distinctive from their source juices. Most alcohols, esters, and acids are fermentation-derived, while terpenes, phenols, aldehydes and ketones are varietal. The Red vinification retained the most varietal volatiles from the must, while the White and Thermo vinifications produced more volatiles during fermentation. Thermovinification reduced the yield of benzoic acid and its derivatives after fermentation. Olfactory analysis identified 47 aroma-active compounds, among which 41 were considered as the major aroma contributors (ethyl benzoate had the highest modified detection frequency).


Assuntos
Aromatizantes/química , Sucos de Frutas e Vegetais/análise , Vaccinium macrocarpon/química , Compostos Orgânicos Voláteis/química , Vinho/análise , Fermentação , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise
4.
Bioresour Technol ; 297: 122482, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31812913

RESUMO

To comprehensively investigate the effect of different air humidity conditions on the performance and odor emission in composting technology, a full-scale experiment was conducted simultaneously in the regions with low air relative humidity (Kunming) and high relative air humidity (Xishuangbanna), Yunnan province. The results showed that: In the regions with low relative air humidity, similar performances were found on organic matter degradation and germination index values in windrow and trough composting. Windrow composting got lower H2S emission, but higher NH3 release comparing with trough composting. Windrow composting was more susceptible to high relative air humidity. The degradation rate and germination index were 22% and 28% lower than those in trough composting. Therefore, the trough composting was recommended in the areas with high relative air humidity, while suitable NH3 mitigation measure should be considered.


Assuntos
Compostagem , China , Umidade , Odorantes , Solo
5.
Bioresour Technol ; 297: 122518, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31812915

RESUMO

A membrane-covered composting system was used to investigate the odor emission and microbial community succession during biogas residue composting. Results showed that in comparison with the control (CK) group, the NH3 and H2S emissions outside the membrane of the membrane-covered (CT) group decreased by 58.64% and 38.13%, respectively. The nitrogen preservation rate of the CT group was increased by 17.27% in comparison with the CK group. Moreover, the ammonium nitrogen and nitrate nitrogen contents of the CT group were 37.68% and 11.77% higher than those of the CK group, respectively. Microbial analysis showed that the average abundance and co-occurrence rate of ammonification bacteria dominated by Pseudomonas and Bacillus in the CT group were lower than those in the CK group, and the abundance of anaerobic sulfate-reducing bacteria (SRB) dominated by Desulfovibrio in the CT group was higher than that in the CK group.


Assuntos
Compostagem , Microbiota , Biocombustíveis , Nitrogênio , Odorantes , Solo
6.
J Sci Food Agric ; 100(3): 1328-1335, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31743449

RESUMO

BACKGROUND: In recent years, mini-watermelons have increased in popularity. To maintain production and quality standards, various agronomic techniques have been applied. For the Cucurbitaceae family, grafting technique has been used to improve resistance to abiotic stresses, crop productivity and fruit qualitative characteristics. There is some previous literature on this matter, but no information on the influence of grafting on the aroma compounds of mini-watermelons is available. Hence, our research aimed to evaluate the effect of some rootstocks, which were selected on the basis of their tolerance to pathogens, on the quality of mini-watermelons, with particular attention to the volatile aroma compounds. RESULTS: Volatile aroma compounds were analysed using solid-phase microextraction-gas chromatography-mass spectrometry. The most represented compounds were C6 and C9 aldehydes and alcohols, which characterize the fruit aroma of the Cucurbitaceae family: (Z)-2-nonenal, (E,Z)-2,6-nonadienal, (Z)-3-nonen-1-ol and (Z,Z)-3,6-nonadien-1-ol were prevalent. Quantitative differences resulted in relation to the various selected rootstocks. Among these, the RS841 rootstock was found to be the most suitable for maintaining yield, quality parameters, sensory characteristics and volatile aroma compounds of mini-watermelon fruits. CONCLUSIONS: The results highlighted that the rootstock, as for other Cucurbitaceae varieties, influences fruit quality and plant yield also for the mini-water melon; the results show the importance of screening for rootstock/scion combinations in order to select a graft able to provide resistance to abiotic stresses, and at the same time improve yield and fruit quality. © 2019 Society of Chemical Industry.


Assuntos
Citrullus/química , Produção Agrícola/métodos , Odorantes/análise , Compostos Orgânicos Voláteis/química , Álcoois/análise , Aldeídos/análise , Citrullus/crescimento & desenvolvimento , Frutas/química , Frutas/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas
7.
J Agric Food Chem ; 68(2): 584-590, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31623437

RESUMO

Flavor stability is a significant concern to brewers as the staling compounds impart unpleasant flavor to beer. Thus, yeasts with antistaling ability have been engineered to produce beer with improved flavor stability. Here, we proposed that increasing the NADH availability of yeast could improve the flavor stability of beer. By engineering endogenous pathways, we obtained an array of yeast strains with a higher reducing activity. Then, we carried out beer fermentation with these strains and found that the antistaling capacities of the beer samples were improved. For a better understanding of the underlying mechanism, we compared the flavor profiles of these strains. The production of staling components was significantly decreased, whereas the content of antistaling components, such as SO2, was increased, in line with the increased antistaling ability. The other aroma components were marginally changed, indicating that this concept was useful for improving the antistaling stability without changing the flavor of beer.


Assuntos
Cerveja/análise , Aromatizantes/metabolismo , NAD/metabolismo , Saccharomyces/metabolismo , Fermentação , Engenharia Genética , Odorantes/análise , Saccharomyces/genética
8.
Waste Manag ; 102: 371-379, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31731256

RESUMO

Peracetic acid (PAA) is an environmentally friendly disinfectant and oxidizer used in several water and wastewater treatment applications. In the present study, PAA was utilized for the conditioning of municipal wastewater sludge before thickening and dewatering. It was shown that PAA can effectively prevent odor formation (i.e., H2S and NH3) and provide hygienization (using E. coli and Salmonella as indicators). Phytotoxicity can be prevented by controlling the amount PAA-conditioned sludge that is mixed in the soil to be fertilized. The required PAA dose for hygienization was relatively high (480 mg 100% PAA perL sludge) but the results indicated that other sludge stabilization processes are not necessarily required. Therefore, the proposed process involving PAA could be feasible in cases where limited land area is available for sludge processing or quick conditioning of sludge is required.


Assuntos
Ácido Peracético , Águas Residuárias , Desinfecção , Escherichia coli , Odorantes , Esgotos , Eliminação de Resíduos Líquidos
9.
Water Res ; 169: 115222, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31675609

RESUMO

Benthic cyanobacteria are a nuisance because they produce highly potent toxins and taste and odour compounds. Despite this, benthic cyanobacteria remain far less studied than their planktonic counterparts. For example, little is known about their growth or the seasonality of their secondary metabolite production. Moreover, sampling and monitoring techniques commonly used for the survey of planktonic species are not necessarily applicable to benthic forms. This study aimed to develop and validate a new sampling device for the routine monitoring of benthic mats. Molecular monitoring techniques were established and validated on environmental samples collected in a South Australian reservoir (SA-L2). A total of eight qPCR assays were applied to samples in order to track seasonal variations in cyanobacteria concentrations and associated secondary metabolite production. Next Generation Sequencing was utilised to conduct a microbial community composition analysis and to select the most appropriate substrate material for the sampling of benthic cyanobacteria. The concentration of the secondary metabolites geosmin and 2-methyl-isoborneol were quantified using High-Performance Liquid Chromatography, and concentrations of key nutrients (N, P) were quantified in water samples. The sampling device designed proved efficient and easy to use in the field. The qPCR assay designed for the amplification of the cyanobacterial MIB synthase had a high efficiency with a minimum limit of quantification of 4 cell-equivalents per reaction and identified a potential source of MIB in SA-L2 Reservoir. The peak season for benthic growth and secondary metabolite production was observed in spring. Proportionally, 35% of the variability in water geosmin concentrations can be explained by benthic actinobacterial and cyanobacterial activity, showing that freshwater benthic mats represent a significant source of taste and odour compounds.


Assuntos
Cianobactérias , Austrália , Água Doce , Odorantes , Paladar
10.
J Agric Food Chem ; 68(1): 267-278, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31833769

RESUMO

Gas chromatography-olfactometry coupled with sensory analysis and partial least-squares regression (PLSR) analysis led to the identification of the odorants responsible for the different flavors of four yeast extracts. Sensory analysis showed that LA00L had an intense sulfurous attribute, and LA00 was characterized by fatty and green notes, FA31 exhibited the floral odor, while KA02 had strong phenolic, animal, fermented, roasted, and caramellic notes. A total of 37 key aroma compounds with odor activity values greater than 1 were determined. 2,4-Di-tert-butylphenol and methional were the most potent aroma compounds. In addition, the key aroma compounds in LA00L were nonanal, dimethyl disulfide, and γ-decalactone. Octanal, dimethyl disulfide, and benzeneacetaldehyde were the key aroma compounds in LA00. In FA31, styrene, benzeneacetaldehyde, and acetophenone were the key aroma compounds, while indole, 2-methoxyphenol, benzeneacetaldehyde, and p-cresol contributed significantly to the aroma of KA02. PLSR showed that p-cresol and indole were significantly responsible for the phenolic and animal notes inducing the off-flavor (yeasty odor) of yeasty extracts. More significantly, indole was first reported to have an important effect on yeasty odor.


Assuntos
Aromatizantes/química , Odorantes/análise , Saccharomyces cerevisiae/química , Compostos Orgânicos Voláteis/química , Adulto , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Masculino , Pessoa de Meia-Idade , Olfato , Adulto Jovem
11.
J Sci Food Agric ; 100(3): 945-952, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31489633

RESUMO

BACKGROUND: Watermelon is appreciated for its nutritional properties and for its flavor. Among the flavor-active compounds that it contains, volatiles play a key role being responsible for aroma. Recent breeding activity has led to the release of mini-watermelons with reduced fruit weight. This paper reports on the characterization of aroma profiles of 'Rugby' and 'Cuoredolce®' novel mini-watermelon cultivars at the ripening stage. The main volatiles were identified and quantified using headspace solid-phase microextraction gas-chromatography mass spectrometry (HS-SPME-GC-MS), and their concentrations were correlated with the E-nose profile. The potential contribution of volatile compounds to the fruit aroma was evaluated by computing the odor activity values (OAV). RESULTS: Twenty main volatile compounds were identified: aldehydes (9), alcohols (4), ketones (2), and terpenes and terpenoids (5). C-9 aldehydes and alcohols were the prevalent compounds. The two cultivars differed in precocity, with 'Rugby' being riper from the early stage considered. Many apocarotenoids with desirable olfactory notes were detected in the volatile profile of 'Rugby'. Four e-nose sensors' signals significantly changed with variety and ripening stage: W1W and W2W were positively correlated and W6S was negatively correlated with all identified volatiles, while W3S showed a negative correlation with 6-methyl-5-hepten-2-one, the major lycopene catabolite. CONCLUSIONS: The aroma profiles described here contribute to the characterization of 'Cuoredolce®' and 'Rugby' mini-watermelon cultivars. Electronic-nose measurement was able to discriminate between cultivars and, to a lesser extent, among ripening stages. © 2019 Society of Chemical Industry.


Assuntos
Citrullus/química , Frutas/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/química , Citrullus/classificação , Citrullus/crescimento & desenvolvimento , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/isolamento & purificação
12.
Huan Jing Ke Xue ; 41(1): 304-312, 2020 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854931

RESUMO

In order to deal with low dissolved oxygen black odor water body of Guangdong-Hong Kong-Macao Greater Bay Area, the nitrogen metabolic capacity of ammoniated bacteria, nitrifying bacteria and denitrifying bacteria under low dissolved oxygen concentration was studied, and the relationship between denitrification efficiency and nitrogen conversion of different bacteria was clarified, which provided theoretical basis for the treatment of black odor water of Guangdong-Hong Kong-Macao Greater Bay Area. Nitrogen conversion characteristics of ammoniated bacteria (Staphylococcus sp. Ay), nitrifying bacteria (Microbacterium sp. Xw), and denitrifying bacteria (Arthrobacter sp. Fy) in simulated wastewater were detected by different concentration of bacteria and different concentration of substrates. The nitrogen metabolism of Ay, Xw and Fy in black odor water at the same concentration under low dissolved oxygen condition and the characteristics of nitrogen metabolism in different concentrations of black odor water were studied. The results showed that the bacterial concentration of Ay bacterium agent increased three times, but the ammoniation efficiency did not multiply. It indicated that increasing the concentration of ammoniated bacterium was not the best way to increase the ammoniation rate. Xw bacteria have a significant effect on the change of nitrate concentration. At 60 h, the nitrate concentration was increased 180% at low bacterial concentration, was 231% at a high bacterial concentration. Fy denitrification efficiency was high, that nitrate nitrogen can be removed quickly at lower concentration. Appropriate increase of total nitrogen concentration can increase the ammoniation efficiency of Ay microbial agent, but too high would inhibit the nitrogen metabolism efficiency of Ay microbial agent. The concentration of nitrate nitrogen of Xw bacterium reagent was increased (3736%) when the total nitrogen was 25 mg·L-1. The Fy microbial agent has no obvious effect on ammonia nitrogen removal. When the total nitrogen concentration was 25 mg·L-1, the removal rate of nitrate by Fy bacterium was the best. Overall, the results showed that the concentration of ammoniated bacteria and denitrifying bacteria could meet the need of nitrogen metabolism, and the nitrifying bacteria could increase the nitrate nitrogen synthesis rate with the increase of the concentration of nitrifying bacteria. In a certain range, increasing the concentration of substrate could increase the efficiency of nitrogen metabolism of bacterial agents, and excessive concentration would inhibit the effect of nitrogen metabolism. The study provides data support for the problem of black odor water in Guangdong-Hong Kong-Macao Greater Bay Area.


Assuntos
Bactérias/metabolismo , Desnitrificação , Nitrogênio/metabolismo , Odorantes , Oxigênio , Poluição da Água , Baías , Hong Kong , Nitrificação , Água do Mar , Águas Residuárias , Purificação da Água
13.
Food Chem ; 307: 125553, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31654952

RESUMO

Aroma contribution of individual esters has been studied in complex mixtures mimicking red wine models. A mixture containing 14 ethyl esters at concentrations found in wine (V1) was prepared and kept as reference. Isointense and qualitatively similar aroma vectors with a reduced number of esters (V2-V7) were prepared. Those vectors were introduced in two reconstituted wines to assess whether simpler vectors could replace V1 without compromising wine quality. In the simpler young wine model, V1 could be replaced by a vector containing just 3 odorants (ethyl 2-methylbutyrate, ethyl butyrate and hexanoate). In the oaky model, a vector containing just ethyl 2-methylbutyrate (V7) could replace V1 without any discernible sensory change. Results also reveal that sub- or perithreshold odorants play outstanding roles on the overall odour intensity of the mixture and that aroma simplification concomitantly implies an increase in the amount of odorant required to keep the intensity of the aroma vector.


Assuntos
Ésteres/análise , Odorantes/análise , Vinho/análise
14.
Ann Otol Rhinol Laryngol ; 129(1): 39-45, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31416326

RESUMO

BACKGROUND: Olfactory dysfunction is an important facet of numerous disease states ranging from sinonasal disease to neurocognitive disorders. Due to expense and/or logistical barriers, objective olfactory testing is not common. We describe the creation of a novel, essential oil-based smell test, Affordable Rapid Olfaction Measurement Array (AROMA), composed at 14 scents at different concentrations and demonstrate correlation of AROMA with the University of Pennsylvania Smell Identification Test (UPSIT), patient age, Sinonasal Outcomes Test (SNOT-22), and perceived loss of smell. METHODS: AROMA was developed for point-of-care olfactory testing and compared to the UPSIT, as well as subjective outcome measures as noted above. About 37 healthy controls were prospectively recruited to assess the reliability of AROMA using a test-retest protocol. An additional cohort of 38 participants with sinonasal disease were prospectively recruited to complete the AROMA and UPSIT, and were compared with a cohort of 30 healthy controls. Spearman correlation correlated AROMA and UPSIT results, patient age, SNOT-22, and perceived loss of smell. RESULTS: AROMA demonstrated good test-retest reliability (r = 0.85, P < .001). Spearman's rho correlation of AROMA to UPSIT was statistically significant at ρ = 0.75 (P < .001). SNOT-22, age, and perceived sense of smell were all significantly correlated with both AROMA (ρ = -0.548, -0.557, -0.642, respectively) and UPSIT (ρ = -0.367, -0.460, -0.552, respectively). CONCLUSION: AROMA has a strong correlation with UPSIT and may be more strongly correlated with sinonasal outcomes. Additionally, AROMA is reusable; level of odorant is not static; and AROMA can test both odor detection and identification. LEVEL OF EVIDENCE: 2b.


Assuntos
Odorantes , Óleos Voláteis , Transtornos do Olfato/diagnóstico , Adulto , Estudos de Casos e Controles , Técnicas e Procedimentos Diagnósticos/economia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Imediatos , Limiar Sensorial
15.
Food Chem ; 306: 125623, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31606633

RESUMO

In this study, apple juice was fermented using Hanseniaspora osmophila X25-5 in pure culture as well as mixed culture with Torulaspora quercuum X24-4, which was inoculated simultaneously or sequentially. H. osmophila inhibited the growth of T. quercuum, while T. quercuum had little effect on the growth of H. osmophila. The simultaneous fermentation consumed relatively more sugar and resulted in the highest ethanol content. The production of organic acids varied depending on the yeast species employed and inoculation modality. Esters and alcohols were the main volatile families produced during fermentation, while ethyl esters and terpenes contributed most to the temperate fruity aroma. Gas chromatography-olfactometry (GC-O) showed that 3-methyl-1-butanol, ethyl 2-methylbutanoate, phenylethyl alcohol, ß-phenethyl acetate, and ß-damascenone were the most potent odorants in all samples. This study suggested that simultaneous fermentation with H. osmophila and T. quercuum might represent a novel strategy for the future production of cider.


Assuntos
Acetatos/análise , Fermentação , Hanseniaspora/metabolismo , Malus/metabolismo , Odorantes/análise , Torulaspora/metabolismo , Bebidas Alcoólicas , Cromatografia Gasosa , Ésteres/análise , Frutas/química , Norisoprenoides/análise , Olfatometria , Vinho/análise
16.
Food Chem ; 302: 125337, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31419770

RESUMO

The composition of volatile compounds in Korla fragrant pears was determined using headspace solid-phase microextraction followed by a gas chromatography-mass spectrometry analysis using fruits at 30, 90, and 150 days after bloom. Hexanal, (E)-2-hexenal, 1-hexanol, (E)-2-hexen-1-ol, (Z)-3-hexen-1-ol, and hexyl acetate were identified as the major compounds. The composition of volatile compounds was associated with fatty acid concentrations and key enzyme activity in the lipoxygenase pathway. In vitro linoleic and linolenic acid feeding experiments conducted using cubes of fruit flesh demonstrated that the concentrations of volatile esters, such as hexyl acetate, in the treated fruits increased significantly after incubation for 12 h compared with those in the control fruits, which was accompanied by a reduction in aldehyde and alcohol concentrations (p < 0.05 or p < 0.01). However, the treatments did not significantly influence the enzyme activity and expression of genes encoding the enzymes.


Assuntos
Frutas/química , Odorantes/análise , Pyrus/química , Pyrus/fisiologia , Compostos Orgânicos Voláteis/análise , Aldeídos/análise , Ésteres/análise , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Análise de Alimentos/métodos , Frutas/efeitos dos fármacos , Frutas/fisiologia , Cromatografia Gasosa-Espectrometria de Massas/métodos , Regulação da Expressão Gênica de Plantas , Hexanóis/análise , Ácido Linoleico/farmacologia , Pyrus/efeitos dos fármacos , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/metabolismo , Ácido alfa-Linoleico/farmacologia
17.
Food Chem ; 302: 125370, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442699

RESUMO

Four Arabica coffees (Brazil, Colombia, Ethiopia, and Guatemala) yield highly variant odours, attesting to the complexities of coffee aroma that command advanced analytical tools. In this study, their volatiles were extracted using solvent-assisted flavour evaporation (SAFE) and headspace solid-phase microextraction (HS-SPME). Due to matrix complexity, some trace odourants were detected in SAFE extracts by aroma extract dilution analysis (AEDA) but remained difficult to quantify by gas chromatography-mass spectrometry (GC-MS). This prompted the application of low energy electron ionisation (EI) coupled with GC-quadrupole time-of-flight (GC-QTOF). Optimal low EI GC-QTOF parameters (EI energy: 15 eV, acquisition rate: 3 Hz) were applied to achieve improved molecular ion signal intensity and reproducibility (relative standard deviation < 10%) across five compounds, which resulted in good linearity (R2 ≥ 0.999) and lowered detection levels (e.g. 0.025 ±â€¯0.005 ng/mL for 4-hydroxy-5-methyl-3(2H)-furanone). Therefore, this method potentially improves the measurement of trace odourants in complex matrices by increasing specificity and sensitivity.


Assuntos
Café/química , Análise de Alimentos/métodos , Odorantes/análise , Compostos Orgânicos Voláteis/análise , Adulto , Brasil , Coffea/química , Colômbia , Etiópia , Feminino , Análise de Alimentos/estatística & dados numéricos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Guatemala , Humanos , Masculino , Pessoa de Meia-Idade , Olfatometria/métodos , Extratos Vegetais/química , Análise de Componente Principal , Reprodutibilidade dos Testes , Microextração em Fase Sólida/métodos , Paladar , Compostos Orgânicos Voláteis/isolamento & purificação
18.
Food Chem ; 304: 125403, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31479993

RESUMO

Current information on the links between the chemistry and hedonic liking of edible mushrooms is scarce. In this study, 84 consumers evaluated the appearance, odor, taste, texture and overall liking of samples of Nordic edible wild mushroom species. Subsequently, multivariate models on the effects of non-volatile compounds, odor-contributing volatile compounds, sensory attributes and hedonic likings were created. The non-volatile compounds were measured with quantitative NMR. The five studied mushroom species were different in their sugar and acid contents. Three consumer clusters were found with species*cluster interactions. Correlations with sensory attributes and chemical components were found, and the multivariate models indicated predictor attributes for each consumer cluster. The results indicate that the sensory properties could be correlated to both volatile and non-volatile compounds, there are consumer clusters with differing likings as regards mushrooms, and these clusters are heterogenic groups with no simple factors such as age explaining their liking scores.


Assuntos
Agaricales/química , Comportamento do Consumidor , Odorantes/análise , Paladar , Compostos Orgânicos Voláteis/análise , Humanos , Espectroscopia de Ressonância Magnética
19.
Food Chem ; 308: 125555, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31655483

RESUMO

Saccharomyces cerevisiae flor yeast is used for the first time in sparkling wine-making. Twenty-six oenological variables and fifty-three volatile metabolites are quantified in the middle (P = 3 bar) and at the end (P = 6 bar) of the second fermentation, carried out in open and closed bottles. A heat-map of volatiles and the fingerprints obtained for ten chemical families and ten odorant series visualize the changes for each condition. Terpenes, fatty acids and volatile phenols increased their contents by pressure effect at the end of the study by 25.0, 7.8 and 2.2%, respectively. The remaining families decrease between 17.4% and 30.1% for furanic compounds and esters in the same stage. A Principal Component Analysis established that nine volatiles are mainly affected by pressure and five by fermentation stage. The use of ethanol-tolerant flor yeasts constitutes an innovative procedure for the enhancement of the sparkling wines diversification.


Assuntos
Dióxido de Carbono/química , Fermentação , Saccharomyces cerevisiae/metabolismo , Vinho/análise , Dióxido de Carbono/análise , Ésteres/análise , Odorantes/análise , Pressão
20.
Food Chem ; 308: 125552, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31677598

RESUMO

The influence of different combinations of Syrah grape maturation degree (19, 21 and 23 °Brix) and maceration times (10, 20 and 30 days) on the volatile profile and aroma potential was evaluated for the first time through different chromatographic platforms (GC × GC/TOFMS, GC-O-OSME, GC-FID and GC/MS). GC × GC/TOFMS analyses resulted in 145 identified compounds and among these 29 were determined to be the most important for wine differentiation. The aroma compounds allowed the discrimination of Syrah wines made with grapes macerated for a shorter time (ten days) due to the higher levels of volatile compounds. The evaluation of these wines through GC-O-OSME together with GC-FID, MS resulted in the designation of 19 °Brix as the most appropriate grape maturation degree to obtain a greater number of volatiles with pleasant odor and higher intensity and persistence. GC × GC/TOFMS allowed five and six co-elutions to be resolved, involving, respectively, ten and twelve important wine compounds.


Assuntos
Odorantes/análise , Vitis/química , Vinho/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Olfatometria , Compostos Orgânicos Voláteis/análise
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