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1.
J Agric Food Chem ; 68(7): 1998-2006, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31984737

RESUMO

Hordenine, a natural constituent of germinated barley, is a biased agonist of the dopamine D2 receptor. This pilot study investigated the biokinetics of hordenine and its metabolites in four volunteers consuming beer equal to 0.075 mg hordenine/kg body weight. A new ultrahigh-performance liquid chromatography method coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method determined maximum plasma concentrations of 12.0-17.3 nM free hordenine after 0-60 min. Hordenine phase-II metabolism was first dominated by sulfation, but later by glucuronidation. The elimination half-lives in plasma were 52.7-66.4 min for free hordenine and about 60/80 min longer for hordenine sulfate and hordenine glucuronide. Urinary excretion peaked 2-3.5 h after consumption and accumulated to 3.78 µmol within 24 h, corresponding to 9.9% of the ingested dose. The observed hordenine levels in plasma seem too low to provoke direct interaction with the dopamine D2 receptor related to food reward, but synergistic or additive effects with alcohol or N-methyltyramine may occur.


Assuntos
Cerveja/análise , Agonistas de Dopamina/farmacocinética , Tiramina/análogos & derivados , Adulto , Cromatografia Líquida de Alta Pressão , Agonistas de Dopamina/sangue , Agonistas de Dopamina/urina , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Receptores de Dopamina D2/química , Receptores de Dopamina D2/metabolismo , Espectrometria de Massas em Tandem , Tiramina/sangue , Tiramina/farmacocinética , Tiramina/urina , Adulto Jovem
2.
J Agric Food Chem ; 68(7): 2155-2163, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31986028

RESUMO

Mandarina Bavaria is a "Special Flavor" hop variety, described as fruity, with pronounced mandarin and citrus, combined with traditional hoppy sensations. The relationship between fruity-citrus intensity and the volatile profile of dry-hopped beers was assessed in order to predict the sensory perception of those dry-hopped beers using the content of selected volatile compounds. For this purpose, two base beers (A and B) that presented statistical differences (p < 0.05) in the composition of volatile compounds and on the sensory perception were dry hopped with 3 g/L Mandarina Bavaria hop. Twenty-four volatiles from hop were quantified during 15 days of dry hopping, while the sensory perception was followed by a certified trained panel. The sensory perception of total hoppy content (in a scale from 0 to 5) can be estimated using a PLS equation (Q2 = 0.654): total hoppy = 1.8 + [myrcene (µg/L) × 7.5 × 10-3] + [2-methylbutyl-2-methylpropanoate (µg/L) × 4.2 × 10-3] + [linalool (µg/L) × 7.2 × 10-3] + [α-humulene (µg/L) × 2.3 × 10-3]). Successful models were also obtained to predict citrus (Q2 = 0.745), green fruit (Q2 = 0.598), and sweet fruit (Q2 = 0.626) characteristics of dry-hopped beers.


Assuntos
Cerveja/análise , Aromatizantes/química , Humulus/química , Compostos Orgânicos Voláteis/química , Humanos , Odorantes/análise , Paladar
3.
Food Chem ; 312: 126087, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31911355

RESUMO

Beer has been one of the most consumed alcoholic beverages worldwide. However, the incorporation of adjuncts in the beer can add new organoleptic and functional characteristics to the beverage. For this, Beauregard sweet potato shows high potential due to being a rich source of starch and many bioactive compounds. The aim of this study was to develop the best process condition to produce a Sweet potato beer with enhanced nutritional and antioxidant properties and good sensory characteristics. Beer samples showed increased antioxidant activity especially due to ß-carotene and their total phenolic content. The phytochemical profile of sweet potato biocompounds demonstrated a direct effect of this adjunct on sensory and functional characteristics of the finished beer. In conclusion, it was found that Beauregard sweet potato is a promising adjunct for beer brewing with nutraceutical properties due to its rich composition of bioactive compounds.


Assuntos
Cerveja/análise , Ipomoea batatas/química , Antioxidantes/análise , Fenômenos Químicos , Fenóis/análise , Amido/química , beta Caroteno/análise
4.
J Agric Food Chem ; 68(1): 206-212, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31808686

RESUMO

The present study aimed to investigate the effects of matured hop bitter acids (MHBAs) on human cognition, mental fatigue, and mood state. In this randomized double-blind placebo-controlled study, 60 healthy adults (age 45-64 years) with self-awareness of cognitive decline were randomly divided into 2 groups and received either orally administered MHBAs (35 mg/day) or placebo for 12 weeks. Cognitive functions and mental states were assessed using neuropsychological tests or questionnaires at baseline and weeks 6 and 12 of the intervention. The change in verbal fluency score at week 6 compared with that at baseline was significantly higher in the MHBAs-treated group compared with that in the placebo group (P = 0.034), and Stroop test score at week 12 was significantly lower in the MHBAs-treated group compared with the placebo group (P = 0.019). Furthermore, subjective fatigue and anxiety at week 12 were significantly improved in the MHBAs-treated group (P = 0.008 and 0.043, respectively) compared with the placebo group. This is the first study to evaluate the effects of bitter ingredients in beer on cognition, subjective mood, and mental fatigue in a clinical trial. Our findings suggest that hop-derived bitter acids might be beneficial for cognition and mood state.


Assuntos
Ácidos/metabolismo , Cerveja/análise , Cognição , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/psicologia , Humulus/química , Humulus/metabolismo , Extratos Vegetais/metabolismo , Ácidos/análise , Afeto , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos
5.
Artigo em Inglês | MEDLINE | ID: mdl-31622171

RESUMO

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 headspace-solid 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).


Assuntos
Cerveja/análise , Análise de Alimentos , Contaminação de Alimentos/análise , Acetaldeído/efeitos adversos , Acetaldeído/análise , Acroleína/efeitos adversos , Acroleína/análise , Cerveja/efeitos adversos , Fermentação , Formaldeído/efeitos adversos , Formaldeído/análise , Furanos/efeitos adversos , Furanos/análise , Humanos , Uretana/efeitos adversos , Uretana/análise
6.
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
7.
J Agric Food Chem ; 68(1): 369-375, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31829586

RESUMO

A sensitive fluorescent DNA hydrogel aptasensor based on the self-assembly of rolling circle amplification (RCA) products was developed for ochratoxin A (OTA) detection in beer. A competitive binding mode of aptamer, complementary sequence, and target was integrated into the DNA hydrogel for OTA detection. The OTA aptamer first combined with the primer to form the hybridized product. Then, in the presence of OTA, the aptamer combined with OTA, which released the primer. The released primer hybridized with the padlock probe to form a circular template, and the RCA reaction was initiated by adding ligase, polymerase, and dNTPs. The fluorescent DNA hydrogel was obtained by adding Cy3-dUTP together with dNTPs, and the fluorescence (FL) intensity of the DNA hydrogel was positively correlated with OTA concentration. Under the optimal experimental conditions, the linear range of the relationship varied from 0.05 ng/mL to 100 ng/mL with a detection limit for OTA of 0.01 ng/mL. The fluorescent DNA hydrogel aptasensor showed good specificity and stability in beer samples. Therefore, the fabricated DNA hydrogel aptasensor shows considerable potential applications in detecting OTA for food safety.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , DNA/química , Hidrogéis/química , Técnicas de Amplificação de Ácido Nucleico/métodos , Ocratoxinas/análise , Aptâmeros de Nucleotídeos/genética , Cerveja/análise , Técnicas Biossensoriais/instrumentação , DNA/genética , Fluorescência , Contaminação de Alimentos/análise , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/instrumentação
8.
J Agric Food Chem ; 68(1): 301-314, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31820631

RESUMO

Xylooligosaccharides (XOS) from woody biomass were evaluated as a substrate for secondary lactic acid bacteria (LAB) fermentation in sour beer production. XOS were extracted from birch (Betula pubescens) and added to beer to promote the growth of Lactobacillus brevis BSO 464. Growth, pH, XOS degradation, and metabolic products were monitored throughout fermentations, and the final beer was evaluated sensorically. XOS were utilized, metabolic compounds were produced (1800 mg/L lactic acid), and pH was reduced from 4.1 to 3.6. Secondary fermentation changed sensory properties significantly, and the resulting sour beer was assessed as similar to a commercial reference in multiple attributes, including acidic taste. Overall, secondary LAB fermentation induced by wood-derived XOS provided a new approach to successfully produce sour beer with reduced fermentation time (from 1-3 years to 4 weeks). The presented results demonstrate how hemicellulosic biomass can be valorized for beverage production and to obtain sour beer with improved process control.


Assuntos
Cerveja/análise , Microbiologia de Alimentos/métodos , Glucuronatos/metabolismo , Lactobacillales/metabolismo , Oligossacarídeos/metabolismo , Extratos Vegetais/metabolismo , Madeira/química , Cerveja/microbiologia , Betula/química , Betula/metabolismo , Betula/microbiologia , Fermentação , Humanos , Concentração de Íons de Hidrogênio , Lactobacillales/crescimento & desenvolvimento , Paladar , Madeira/metabolismo , Madeira/microbiologia
9.
Food Chem ; 309: 125751, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31718839

RESUMO

Development of a novel colorimetric and turn-on fluorescent sensor for potassium metabisulphite (KMS) using graphene oxide stabilized gold nanoparticles (GO-AuNPs) was described. The red color GO-AuNPs was changed to violet while adding 250 × 10-5 M KMS whereas the absorbance band at 523 nm was decreased. The observed changes were ascribed to the leaching of AuNPs from GO. The emission maximum was observed at 448 nm for GO while exciting at 335 nm. However, the GO emission was "turn-off" after the formation of AuNPs on GO surface due to masking of oxygen functional groups responsible for emission. Interestingly, the emission of GO-AuNPs becomes "turn-on" after the addition of 75 × 10-6 M KMS. Further addition of KMS from 150 to 1125 × 10-6 M, the emission intensity of GO-AuNPs linearly increases with the correlation coefficient of 0.9980 and the limit of detection was found to be 9.4 µM L-1/1.2 mg L-1 (S/N = 3).


Assuntos
Ouro/química , Grafite/química , Nanopartículas Metálicas/química , Espectrometria de Fluorescência , Sulfitos/análise , Cerveja/análise , Limite de Detecção , Tamanho da Partícula , Reprodutibilidade dos Testes , Propriedades de Superfície
10.
Food Chem ; 305: 125437, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499290

RESUMO

Total polyphenols and flavonoids content, phenolics profile by HPLC, and antioxidant activity of ten fruit beer produced adding fruits during the fermentation process were analyzed. The fruits were: cherry, raspberry, peach, apricot, grape, plum, orange and apple. Antioxidant activity, total polyphenols and flavonoids content were considerably higher in most of the fruit beers in respect to conventional, no-fruit beers. Cherries beers exhibit the highest values, followed by grape, plum and orange beers. An enrichment was observed in catechin and quercetin content in all fruit beers examined. Myricetin and resveratrol were also detected in most of the fruit beers. Among phenolic acids, an enrichment in chlorogenic, neochlorogenic, p-coumaric and caffeic acids was measured in most of the fruit beers in respect to conventional beers. Our findings show that fruits addition during the fermentation process considerably increased the antioxidant activity of beer and qualitatively and quantitatively improved its phenolics profile.


Assuntos
Antioxidantes/química , Cerveja/análise , Rosaceae/química , Cromatografia Líquida de Alta Pressão , Flavonoides/análise , Flavonoides/química , Frutas/química , Frutas/metabolismo , Fenóis/análise , Fenóis/química , Extratos Vegetais/química , Polifenóis/análise , Polifenóis/química , Rosaceae/metabolismo
11.
Food Chem ; 305: 125382, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31525590

RESUMO

During the mashing process for brewing beer, incomplete degradation of arabinoxylan in barley malt may cause an intense filterability problem. The present study cloned a putative arabinofuranosidase (AnAbf), one of the debranching enzymes, from Aspergillus niger, to explore its application for improving filterability. Recombinant AnAbf (rAnAbf) showed activity towards both synthetic and natural substrates, such as 4-nitrophenyl α-l-arabinofuranoside (pNPαAraf) and malt water extractable arabinoxylan (WEAX), which was maximized at a temperature of 50 °C and pH of 5.5. Metal ions did not increase the activity of rAnAbf, indicating a difference in its C-terminal domain from that of type II GH43 family members. rAnAbf also exhibited a synergistic effect with ß-xylanase against WEAX. The filtration rate of the wort increased by 12.8% after supplementing with rAnAbf during the initial stage of mashing. A slight decrease in viscosity and an unexpected increase in turbidity were observed.


Assuntos
Aspergillus niger/enzimologia , Cerveja/análise , Glicosídeo Hidrolases/metabolismo , Xilanos/metabolismo , Arabinose/análogos & derivados , Arabinose/metabolismo , Endo-1,4-beta-Xilanases , Proteínas Fúngicas/metabolismo , Temperatura Alta , Proteínas Recombinantes/metabolismo
12.
Food Chem ; 312: 125968, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31881442

RESUMO

Recipes for traditional and sour non-alcoholic beers were developed in this study employing a special yeast species Saccharomycodes ludwigii. They were characterized for their basic physicochemical properties, antioxidative activity as well as subjected to the quantitative and qualitative analysis of their biologically-active compounds, and to the sensory assessment. Sour non-alcoholic beers were brewed with the addition of juice from fruits of red-colored Cornelian cherry (Cornus mas L.) variety, which are characterized by naturally sour taste and aroma. Ethyl alcohol content in the beers manufactured ranged from 0.41%v/v in traditional non-alcoholic beers to 0.43%v/v in sour non-alcoholic beers. The final products had a low energy value, ranging from 116 to 148 kcal/500 mL of beer. The sour beers had several times higher antioxidative potential and significantly higher polyphenols concentration compared to the control ones. In addition, they were rich in anthocyanins and iridoids, and presented novel sensory attributes.


Assuntos
Antioxidantes/análise , Cerveja/análise , Cornus/química , Saccharomycetales , Antocianinas/análise , Frutas/química , Iridoides/análise , Polifenóis/análise , Paladar
13.
Food Chem ; 309: 125689, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31767478

RESUMO

A new approach for biogenic amines (BA) determination in fermented beverages was developed coupling ultrafast dansylation conditions with ultra-high-performance liquid chromatography (UHPLC) method. Derivatization conditions for 8 amines analysis were optimized using D-optimal and central composite designs reducing in 88% the reaction time. Dansylated amines were separated on C18 column using a mobile phase composed of ammonium formate buffer and acetonitrile. Detection was performed by UV and fluorescence. Migration from conventional HPLC to UHPLC allowed a 60% reduction in analysis. The developed method was validated following ICH recommendations. Calibration data fitted a linear regression model with R2 were values highest to 0.984. Repeatability and intermediate precision in matrix showed relative standard deviation (RSD) values lower than 4.86 and 11.53%, respectively. Detection and quantification limits ranged from 0.03 to 0.18 and from 0.20 to 0.59 mg mg L-1. BA content in beer and wine samples were 10.53 to 73.17 mg L-1.


Assuntos
Cerveja/análise , Aminas Biogênicas/análise , Cromatografia Líquida de Alta Pressão/métodos , Vinho/análise
14.
J Food Sci ; 84(11): 3303-3311, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31671224

RESUMO

Seven bisphenols, endocrine-disruptor chemicals, were analytically determined for risk assessment in 52 large-consumption beverages collected from the Italian market. The analytes under examination were bisphenol A, bisphenol F, bisphenol E, bisphenol B, bisphenol AF, bisphenol A diglycidyl ether, and bisphenol M. The concentration levels of all bisphenols detected ranged from

Assuntos
Compostos Benzidrílicos/análise , Bebidas/análise , Disruptores Endócrinos/análise , Fenóis/análise , Cerveja/análise , Compostos de Epóxi/análise , Contaminação de Alimentos/análise , Alimentos em Conserva/análise , Humanos , Itália
15.
Artigo em Inglês | MEDLINE | ID: mdl-31596176

RESUMO

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 r2 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.


Assuntos
Cerveja/análise , Contaminação de Alimentos/análise , Microextração em Fase Sólida , Acetaldeído/análise , Acroleína/análise , Formaldeído/análise , Furanos/análise , Cromatografia Gasosa-Espectrometria de Massas , Estrutura Molecular , Medição de Risco , Uretana/análise
16.
J Agric Food Chem ; 67(43): 12044-12053, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31518127

RESUMO

The use of hops in beer brewing is mainly based on its content of bitter acids and aroma compounds. Due to the loss of volatile odorants during wort boiling, the so-called dry hopping is a possibility to intensify the hoppy aroma in the final beer. To clarify the potential of different hop varieties for aroma modulation of beer via dry hopping, key aroma compounds of three different hop varieties were characterized using the sensomics approach. Aroma extract dilution analysis revealed 41 aroma-active compounds, of which 39 were identified via gas chromatography-olfactometry and gas chromatography-mass spectrometry. The highest flavor dilution factor was determined for myrcene with a geranium-like odor. Fourteen substances were quantitated by stable isotope dilution analysis and further two odorants via the internal standard method; all of them revealed odor activity values (OAVs; ratio of concentration to odor threshold) ≥1. Linalool, 3-methylbutanoic acid, myrcene, and dimethyl trisulfide showed the highest OAVs (>1000) in all analyzed hop varieties. For validation of the analytical data, reconstitution models were prepared by adding all quantitated aroma compounds with OAVs ≥ 1 in their naturally occurring concentrations to cellulose as matrix. All three recombinates showed a very high similarity to the aroma profile of the respective hop sample, confirming the correct identification and quantitation of all key aroma compounds.


Assuntos
Aromatizantes/química , Humulus/química , Compostos Orgânicos Voláteis/química , Cerveja/análise , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Odorantes/análise , Olfatometria , Paladar
17.
Talanta ; 205: 120146, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31450401

RESUMO

We developed a highly sensitive and accurate differential method for analyzing chiral and achiral carboxylic acids in Japanese commercial beers, using ultra high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS), based on chiral derivatization combining three isotopic chiral reagents: 12C-DMT-3(S)-Apy, 13C2-DMT-3(S)-Apy, and d6-DMT-3(S)-Apy. By combining these reaction solutions and analyzing the resulting mixture, simultaneous comparative analyses of the three samples could be achieved while offsetting the matrix effects on the samples. Using this approach, it was possible to differentiate the beers according to the type (draft, low-malt, and non-alcoholic), manufacturer, and storage conditions (temperature and storage period), based on the concentrations of carboxylic acids in the beers. Furthermore, we identified α-ketoglutaric acid as a new marker for determining the storage condition of Japanese beers. The proposed method would provide insights into the identification of markers in various fields, such as in biological samples, as well as food and beverages.


Assuntos
Cerveja/análise , Ácidos Carboxílicos/análise , Cromatografia Líquida de Alta Pressão/métodos , Análise de Alimentos/métodos , Limite de Detecção , Espectrometria de Massas/métodos , Ácidos Carboxílicos/química , Temperatura Alta , Indicadores e Reagentes/química , Estereoisomerismo
18.
J Chromatogr A ; 1604: 460467, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31451194

RESUMO

This paper describes the method validation for the simultaneous determination of seven cysteinylated aldehydes, i.e. 2-substituted 1,3-thiazolidines-4-carboxylic acids, using ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS). Authentic reference compounds were first synthesized for identification and quantification purposes. Moreover, nuclear magnetic resonance (1H NMR and 13C NMR) was applied for verification of their structure, while ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) was applied for estimation of the purity. The method for quantification of cysteinylated aldehydes in model solutions has been validated according to the criteria and procedures described in international standards. The synthesized compounds were successfully identified via UHPLC-MS by comparing retention time and MS spectra with the commercial reference compounds. Method validation revealed good linearity (R2 > 0.995) over the range of 0.4-2.2 µg/L to approximately 1000 µg/L, depending on the analyte. The limits of quantification varied from 0.9 to 4.3 µg/L depending on the nature of the compound. Furthermore, evaluation of the method showed good accuracy and stability of the standard solutions. Reported chromatographic recoveries ranged from 112 to 120%. Consequently, the currently described method was applied on malt and beer samples. For the first time, quantification of cysteinylated aldehydes was obtained in malt. In contrast, in fresh beers unambiguous identification of these compounds was not achieved.


Assuntos
Aldeídos/análise , Cerveja/análise , Cromatografia Líquida de Alta Pressão , Análise de Alimentos/métodos , Espectrometria de Massas em Tandem
19.
J Sci Food Agric ; 99(14): 6628-6637, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31393605

RESUMO

BACKGROUND: Many studies have confirmed a wide variation in the phenolic content and antioxidant activity of beers. However, when commercial beers are studied, there is usually no information available on the brewing technology applied. In this study, technological parameters were varied systematically to influence the antioxidant content of beer with a view to improving its flavor stability. High-throughput assays, ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) were investigated as fast analytical methods to evaluate the influence of brewing technology on antioxidant activity. RESULTS: Beers (n = 12) were brewed with systematic technological variations (malt modification, hopping regime) to influence the antioxidant potential. A late hop addition resulted in significantly higher phenolic content (high-performance liquid chromatography with diode-array detection - HPLC-DAD) and antioxidant activity. Raw protein content and malt modification significantly influenced phenolic content and the antioxidant activity of beers hopped at the beginning of wort boiling. Samples were stored under forced and natural conditions and were evaluated by a sensory panel. The decline of bitter iso-α-acids as an analytical marker for oxidative aging was significantly lower in beers brewed from malts with high raw protein content. These samples also had higher antioxidant activity values. Panelists gave higher ratings for beer quality to aged beers with a late hop addition. However, late hopping resulted in enhanced hoppy aroma attributes and therefore an altered aroma profile. CONCLUSIONS: Both antioxidant capacity methods were well suited as fast methods to evaluate brewing raw material and technological influence on antioxidant activity. The appropriate choice of barley malt and the malting regime could be promising tools to enhance the antioxidant activity of traditionally hopped beers. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Antioxidantes/análise , Cerveja/análise , Análise de Alimentos/métodos , Paladar , Humanos , Humulus/química , Capacidade de Absorbância de Radicais de Oxigênio , Fenóis/análise
20.
Anal Chim Acta ; 1077: 273-280, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31307719

RESUMO

As a multifunctional signaling molecule, hydrogen sulfide (H2S) plays an essential role in diverse physiological and pathological processes. The two-photon fluorescence probes detecting H2S selectively in vivo could be useful tools to better study the mechanism of diseases. Then, an efficient two-photon lysosome-specific probe 1 has been developed to detect endogenous H2S in living cells and mice. Probe 1 displays excellent properties with 28-fold fluorescence enhancement, marked color changes in naked-eye and fluorescence, high selectivity and sensitivity, and low detection limit (0.22 µM) to H2S. These remarkable properties of probe 1 enable its practical applications in detecting H2S in environment (wastewater) and food (beer). Moreover, as a two-photon probe under near infrared excitation at 790 nm, probe 1 can monitor the level changes of endogenous H2S of lysosome and tumor in living system with good membrane permeability and high imaging resolution. Specially, the probe detecting H2S distribution in lysosome could provide more evidences to explain the association of target-organelle and H2S.


Assuntos
4-Cloro-7-nitrobenzofurazano/análogos & derivados , Neoplasias da Mama/metabolismo , Corantes Fluorescentes/química , Sulfeto de Hidrogênio/análise , Lisossomos/metabolismo , Naftalimidas/química , 4-Cloro-7-nitrobenzofurazano/síntese química , 4-Cloro-7-nitrobenzofurazano/toxicidade , Animais , Cerveja/análise , Linhagem Celular Tumoral , Colorimetria/métodos , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/toxicidade , Humanos , Limite de Detecção , Camundongos Nus , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Naftalimidas/síntese química , Naftalimidas/toxicidade , Fótons , Espectrometria de Fluorescência/métodos , Águas Residuárias/análise
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