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1.
J Chromatogr A ; 1626: 461362, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797841

RESUMO

Exploring new material as adsorbent for the efficient enrichment of pollutants is always of great significance in analytical chemistry. In this work, a magnetic azobenzene framework (labeled as MAzo) was constructed as a magnetic solid phase extraction (MSPE) adsorbent by a simple and environmentally benign strategy. The MAzo exhibited the attractive features of strong magnetism, outstanding adsorption performance, as well as good reusability. Combining MAzo-based MSPE with high performance liquid-phase chromatography, a simple and effective method was developed for simultaneous determination of four phenylurea herbicides in pear juice and apple juice samples. Under optimized experimental conditions, the method offered low limits of detection of 0.05-0.15 ng mL-1, high recoveries of 86.7-109.2% with RSD less than 7%. Density functional theory calculation indicated that the good adsorption performance of MAzo for PUHs can be ascribed to the strong H-bonding forces and weak π-π interactions. The facile, green, low-cost synthesis method together with the excellent adsorption performance endows the MAzo great application prospect in sample preparation.


Assuntos
Compostos Azo/química , Poluentes Ambientais/análise , Herbicidas/análise , Compostos de Fenilureia/análise , Extração em Fase Sólida/métodos , Adsorção , Cromatografia Líquida de Alta Pressão , Poluentes Ambientais/isolamento & purificação , Sucos de Frutas e Vegetais/análise , Herbicidas/isolamento & purificação , Fenômenos Magnéticos , Malus , Estruturas Metalorgânicas , Compostos de Fenilureia/isolamento & purificação , Pyrus
2.
J Chromatogr A ; 1627: 461398, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823103

RESUMO

A new mode of dispersive solid phase extraction based on in situ formation of adsorbent in aqueous phase has been introduced as an efficient method for the extraction of some pesticide residues in fruit juice samples. In this method, polycarbonate which is an inexpensive polymer is used as an adsorbent for the first time. The method is followed by dispersive liquid-liquid microextraction for more enrichment of the analytes. In the present study, a proper amount of the polymer is dissolved in N,N-dimethyl formamide and the obtained solution is injected into an aqueous phase containing the analytes. After injection, polycarbonate particles are formed and adsorbed the analytes. Then, the adsorbent is separated from the aqueous solution and eluted by acetone. The obtained acetone phase is mixed with 1,1,1-trichloroethane and the mixture is dispersed into deionized water and a cloudy solution is formed. Ultimately, after centrifugation, the obtained sedimented phase containing the extracted analytes is injected into gas chromatography-flame ionization detection. In the proposed method, the adsorbent synthesis step, which often is a time-consuming, expensive, and laborious step in most adsorbent-based sample preparation methods, has been removed. Moreover, there is no need for sonication or vortex agitation. Under the optimized experimental conditions, the relative standard deviation was equal or less than 7% for intra- (n = 6) and inter-day (n = 5) precisions at a concentration of 50 µg L-1 of each pesticide. The limits of detection and quantification were in the ranges of 0.34-1.2 and 1.1-4.0 µg L-1, respectively. In addition, extraction recoveries and enrichment factors varied in the ranges of 44-89% and 220-443, respectively.


Assuntos
Sucos de Frutas e Vegetais/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Resíduos de Praguicidas/análise , Centrifugação , Limite de Detecção , Microextração em Fase Líquida/métodos , Resíduos de Praguicidas/isolamento & purificação , Extração em Fase Sólida , Solventes/química , Triazinas/análise , Triazinas/isolamento & purificação , Água/química
3.
Food Chem ; 332: 127426, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32619948

RESUMO

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


Assuntos
Proteínas Fúngicas/metabolismo , Glicosídeo Hidrolases/metabolismo , Pichia/metabolismo , Saccharomyces cerevisiae/metabolismo , Vinho/análise , Fermentação , Frutas/química , Sucos de Frutas e Vegetais/análise , Sucos de Frutas e Vegetais/microbiologia , Cromatografia Gasosa-Espectrometria de Massas , Norisoprenoides/análise , Norisoprenoides/metabolismo , Odorantes/análise , Pichia/enzimologia , Pichia/crescimento & desenvolvimento , Terpenos/análise , Terpenos/metabolismo
4.
Food Chem ; 332: 127383, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32615383

RESUMO

This study represents a rapid and non-destructive approach based on mid-infrared (MIR) spectroscopy, time domain nuclear magnetic resonance (TD-NMR), and machine learning classification models (ML) for monitoring soluble pectin content (SPC) changes in orange juice. Current reference methods of SPC in orange juice are laborious, requiring several extractions with successive adjustments hindering rapid process intervention. 109 fresh orange juices samples, representing different harvests, were analysed using MIR, TD-NMR and reference method. Unsupervised algorithms were applied for natural clustering of MIR and TD-NMR data in two groups. Analyses of variance of the two MIR and TD-NMR datasets show that only the MIR groups were different at 95% confidence for SPC average values. This approach allows build classification models based on MIR data achieving 85% and 89% of accuracy. Results demonstrate that MIR/ML can be a suitable strategy for the quick assessment of SPC trends in orange juices.


Assuntos
Citrus sinensis/química , Sucos de Frutas e Vegetais/análise , Aprendizado de Máquina , Pectinas/química , Citrus sinensis/metabolismo , Análise por Conglomerados , Humanos , Espectroscopia de Ressonância Magnética , Pectinas/metabolismo , Análise de Componente Principal , Espectrofotometria Infravermelho
5.
Food Chem ; 332: 127382, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32619943

RESUMO

Sea buckthorn (Hippophaë rhamnoides L.) berries have high biological value as a rich source of phenolic compounds, fatty acids and vitamins A, C, E. Due to the high organic acid content and sour taste, the fruits are rarely used in juice production. Therefore, the study aimed to determine the metabolic activity of Lactobacillus plantarum, Lactobacillus plantarum subsp. argentoratensis and Oenococcus oeni strains along with the dynamics of changes in organic acids, sugars, phenolic compounds, and antioxidant activity during 72-h fermentation of 100% sea buckthorn and mixed with apple (1:1) juices. The strongest malolactic conversion was in mixed juices (to 75.0%). The most efficient strains were L. plantarum DSM 10492, 20174 and 6872. L. plantarum strains caused an increase in flavonols and antioxidant activity of sea buckthorn-apple juices. The results can be used to select conditions and strains in industrial-scale fermentation, to produce novel sea buckthorn products and increase their consumption.


Assuntos
Antioxidantes/química , Sucos de Frutas e Vegetais/análise , Ácido Láctico/metabolismo , Malatos/metabolismo , Fenóis/metabolismo , Açúcares/metabolismo , Fermentação , Flavonóis/química , Flavonóis/metabolismo , Frutas/química , Frutas/metabolismo , Hippophae/química , Hippophae/metabolismo , Concentração de Íons de Hidrogênio , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/metabolismo , Malus/química , Malus/metabolismo , Oenococcus/crescimento & desenvolvimento , Oenococcus/metabolismo , Fenóis/química
6.
Food Chem ; 332: 127339, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32659697

RESUMO

Non-targeted NMR-based approach has received great attention as a rapid method for food product authenticity assessment. The availability of a database containing many comparable NMR spectra produced by different spectrometers is crucial to develop functional classifiers able to discriminate rapidly the commodity class of a given food product. Nevertheless, variability in spectrometer features may hamper the production of comparable spectra due to inherent variations in signal resolution. In this paper, we report on the development of a class-discrimination model for grape juice authentication by application of non-targeted NMR spectroscopy. Different approaches for the pre-treatment of data will be described along with details about the model validation. The developed model performed excellently (95.4-100% correct predictions) even when it was tested against 650 spectra produced by 65 spectrometers with different configurations (magnetic field strength, manufacturer, age). This study may boost the use of non-targeted NMR methods for food control.


Assuntos
Análise de Alimentos/métodos , Qualidade dos Alimentos , Campos Magnéticos , Espectroscopia de Ressonância Magnética/métodos , Bases de Dados Factuais , Sucos de Frutas e Vegetais/análise , Vitis/química
7.
Food Chem ; 332: 127486, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32663756

RESUMO

Activated complex theory (ACT), apart from Van 't Hoff equation, has long been applying as an alternative tool to connect the kinetics (reaction rate constant, k) and thermodynamics parameters (including standard enthalpy of activation, △H++; standard entropy of activation, △S++; standard Gibbs free energy of activation, △G++). The study mainly focuses on ACT application in food systems, especially oil and fruit juice processing. Considering there are several improper calculations or mistakes often found in papers published recently in 2014-2019, three considerations are presented when applying the ACT, including 1) Understand that the reaction should be a single chemical elementary step; 2) Ensure that the units used should be consistent; 3) Effectively analyze the kinetics and thermodynamic parameters by choosing proper temperatures. This study is expected to further improve the understanding and correct application of this well-known theory in future work.


Assuntos
Manipulação de Alimentos/métodos , Tecnologia de Alimentos , Entropia , Tecnologia de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Cinética , Óleos/química , Temperatura , Termodinâmica
8.
J Chromatogr A ; 1625: 461340, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709363

RESUMO

In this study, a magnetized polyethylene composite has been prepared using ball milling procedure and employed as an efficient sorbent in magnetic dispersive solid phase extraction combined with dispersive liquid-liquid microextraction. This method has been utilized for the extraction and preconcentration of some pesticides from fruit juices prior to their quantification by gas chromatography-flame ionization detection. The prepared sorbent consisted of the natural iron oxide (obtained from sand) coated with polyethylene. In the present work, first a few mg of the magnetic composite is added into an aqueous solution containing the analytes and vortexed. After that the analytes are eluted with iso-propanol from the surface of the composite particles separated in the presence of a strong external magnetic field. For further enrichment of the analytes, 1,2-dibromoethane (at µL-level) as an extraction solvent is mixed with the obtained eluent and hastily injected into deionized water. The composite was characterized using techniques including vibrating sample magnetometry, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller nitrogen sorption, and Fourier transform infrared spectrophotometry. Under optimal conditions, the method provided low limits of detection (0.94-1.9 µg L-1) and quantification (3.2-5.9 µg L-1), high enrichment factors (570-692), good linearity (r2 ≥ 0.994), and satisfactory repeatabilities (relative standard deviations ≤ 8% for intra- and inter-day precisions at a concentration of 15 µg L-1 of each analyte).


Assuntos
Fenômenos Magnéticos , Praguicidas/isolamento & purificação , Polietileno/química , Polietileno/síntese química , Adsorção , Centrifugação , Cromatografia Gasosa , Sucos de Frutas e Vegetais/análise , Concentração de Íons de Hidrogênio , Limite de Detecção , Microextração em Fase Líquida , Concentração Osmolar , Praguicidas/análise , Praguicidas/química , Reprodutibilidade dos Testes , Extração em Fase Sólida , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de Tempo , Difração de Raios X
9.
J Chromatogr A ; 1623: 461214, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505267

RESUMO

Plant hormones (PHs) are a type of pesticide that can potentially affect human health. Therefore, their quantitative detection is particularly important. In this study, a green and economic method for the simultaneous extraction and determination of four PHs, namely thidiazuron, forchlorfenuron, 1-naphthylacetic acid, and 2-naphthoxyacetic acid, in watermelon juice was developed by using m-aminophenol-urea-glyoxal resin as the adsorbent for pipette tip solid phase extraction (PT-SPE) coupled with liquid chromatography. The resin was synthesized via a simple (one pot hydrothermal synthesis) and green (ethanol as the solvent and glyoxal as crosslinking agent) process. The synthesized resin possesses multiple functional groups (hydroxyl, amino, and imino, among others), high adsorption capacity, larger specific surface area than the urea-glyoxal resin and m-aminophenol-glyoxal resin, and can be regenerated easily. The PT-SPE device is simple, cheap, and easy to obtain, and the adsorbent dosage is only 5.0 mg. The proposed method has a wide linear detection range, high recovery, good precision, and high sensitivity, and satisfies the measurement requirements for detecting trace levels of PHs in fruits and vegetables.


Assuntos
Aminofenóis/química , Citrullus/química , Sucos de Frutas e Vegetais/análise , Glioxal/química , Reguladores de Crescimento de Planta/análise , Resinas Vegetais/química , Extração em Fase Sólida/métodos , Ureia/química , Adsorção , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Ácidos Naftalenoacéticos/química , Praguicidas , Reprodutibilidade dos Testes
10.
J Chromatogr A ; 1623: 461197, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505286

RESUMO

Trifluoromethyl covalent organic framework (CF3-COF) is facilely synthesized at room temperature using for solid-phase microextraction (SPME). The CF3-COF coating displays an improved extraction performance for per- and polyfluorinated alkyl substances (PFASs) comparing to amorphous polymer coating, non-contained fluorine covalent organic framework coating and commercially available SPME coating. The fluorine affinity of trifluoromethyl in CF3-COF for PFASs is demonstrated using the density functional theory calculation. Following the microextraction with CF3-COF-coated fiber, the targeted PFASs are eluted with 1 mL acetonitrile and quantified by ultrahigh performance liquid chromatography tandem mass spectrometry. The low limits of detection are 0.1-0.7 pg g-1 for milk and 0.2-0.8 pg g-1 for milk powder, suggesting the outstanding sensitivity. The precision for the method ranges between 2.9 and 9.9%. The fiber-to-fiber repeatability is in the range of 4.2-9.5%. Under the optimum conditions, the relative recoveries are 91.0-110% with RSDs ≤ 10% for milk and 89.8-111% with RSDs ≤ 10% for milk powder.


Assuntos
Hidrocarbonetos Halogenados/isolamento & purificação , Estruturas Metalorgânicas/química , Leite/química , Microextração em Fase Sólida/métodos , Adsorção , Animais , Citrullus/química , Sucos de Frutas e Vegetais/análise , Glioxal/química , Concentração de Íons de Hidrogênio , Estruturas Metalorgânicas/síntese química , Fenóis/química , Reprodutibilidade dos Testes , Resinas Sintéticas/química , Ureia/química
11.
An Acad Bras Cienc ; 92(2): e20190328, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32556050

RESUMO

The degradation kinetics of vitamin C in different citrus juice types (tangerine, grapefruit, orange and lime) were investigated during four hours storage at temperatures of 4 and 25°C under different storage conditions in terms of light and oxygen presence. The loss of vitamin C at each sample followed the first-order kinetic model. During storage, predicted half-life of vitamin C ranged from 137.586 to 467.486 min for tangerine; 105.444 to 203.100 min for grapefruit; 365.702 to 1044.668 min for orange and 540.076 to 722.016 min for lime juices. These results indicated that the highest and lowest retentions of vitamin C were observed in orange and grapefruit juices respectively during storage. Additionally, storage time, light penetration and oxygen presence were the most effective factors on vitamin C degradation while the storage temperature revealed no significant effect on the vitamin C content.


Assuntos
Ácido Ascórbico/análise , Citrus , Armazenamento de Alimentos , Sucos de Frutas e Vegetais/análise , Meia-Vida , Cinética , Temperatura
12.
Food Chem ; 329: 127130, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32516707

RESUMO

Untargeted metabolomics was used to investigate the differences between orange juices from concentrate or not. Although no distinctive separation could be observed from principal component analysis for all samples, student's t-test, fold change, orthogonal projection to latent structures discriminant and detection rate analyses were conducted to find the latent potential markers. Subsequently, 91 and 42 potential markers were defined in positive/negative mode. Thirteen of them, l-glutamine, carvone, erucamide, lysoPE (16:0/0:0), oleic acid, α-linolenic acid and 7 tripeptides (reported for the first time in orange juice) were identified with standards. A partial least squares discriminant analysis model, based on the potential markers in positive mode by direct analysis in real time mass spectrometry-quadrupole time of flight (DART-QTOF) with 9 s acquisition time, was constructed and validated with 97% and 95% accuracy for training and test. The model was applied to commercial samples successfully, and an NFC brand was found highly suspicious.


Assuntos
Citrus sinensis/metabolismo , Sucos de Frutas e Vegetais/análise , Biomarcadores , Cromatografia Líquida de Alta Pressão , Citrus sinensis/química , Análise Discriminante , Análise dos Mínimos Quadrados , Espectrometria de Massas , Metabolômica
13.
Food Chem ; 330: 127120, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32526646

RESUMO

Enzymatic hydrolysis of plant-derived proteins can improve their quality by offering opportunities for food applications. In this study, three proteolytic enzymes (pepsin, trypsin, Alcalase®) were used, alone or combined, to produce faba bean protein hydrolysates (PHs). Their functional, nutritional and antioxidant properties were evaluated, and the peptidomic profile was assessed by LC-MS/MS. Hydrolysis improved solubility of faba proteins at acidic and neutral pH, and their antioxidant properties. Peptidomic analysis identified 2031 peptides in the different PHs. Among them, 9 showed 100% homology with previously known antioxidant peptides and several others had antioxidant motifs in their sequences. Sensory data analysis showed that after addition of PHs to apple juice, no significant differences were perceived between control and some of the PHs. This study demonstrates that enzymatic hydrolysis enhances the functional and antioxidant properties of faba bean proteins. Specifically, hydrolysates can be used as functional food ingredients to produce fortified beverages.


Assuntos
Antioxidantes/química , Sucos de Frutas e Vegetais/análise , Malus/química , Proteínas de Plantas/química , Hidrolisados de Proteína/química , Vicia faba/química , Cromatografia Líquida , Hidrólise , Malus/metabolismo , Proteínas de Plantas/metabolismo , Hidrolisados de Proteína/metabolismo , Sementes/química , Sementes/metabolismo , Vicia faba/metabolismo
14.
Food Chem ; 328: 126967, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32505057

RESUMO

Different particle sizes in cloudy apple juice were obtained following filtration with different mesh sizes (100, 200, 300, and 400-mesh). The effects of cloud particle size on the stability, nutrient content, and volatile flavor of cloudy apple juice were evaluated. With increasing mesh number, particle size decreased (p < 0.05) and particle shape changed. Particle size had an effect on volatile flavor compounds, especially nitrogen oxides, alcohols, and aromatic compounds. The content of pectin and total phenol decreased with decreasing particle size, while the content of soluble protein was not affected. The reduction of cloud particle size increased absolute value of ζ-potential, cloud stability, and apparent viscosity and decreased turbidity and cloud values. Pearson correlation analysis showed that there was a strong correlation between particle size and quality indicators, except for soluble protein.


Assuntos
Aromatizantes/química , Sucos de Frutas e Vegetais/análise , Malus/química , Álcoois/análise , Malus/metabolismo , Microscopia de Força Atômica , Óxidos de Nitrogênio/análise , Tamanho da Partícula , Fenóis/análise , Viscosidade
15.
Food Chem ; 331: 127259, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32562977

RESUMO

Production of high-quality healthy foods through sustainable methodologies is an urgent necessity. High pressure homogenization (HPH) is an interesting alternative to obtain premium citrus juices, but its effects on bioactive compounds are unclear. There was studied the influence of HPH (150 MPa) and pasteurization (92 °C for 30 s and 85 °C for 15 s) processing on physicochemical properties and in vitro bioaccessibility of carotenoids and flavonoids in orange juices. Regarding fresh juice, physicochemical properties of samples remained unchanged although cloudiness was improved by homogenization. Pasteurization did not affect total carotenoids content and retinol activity equivalents (RAE) of juices whereas homogenization yielded a significant reduction (1.37 and 1.35-fold, respectively). Interestingly, particle size reduction from homogenization drastically enhanced (about 5-fold) bioaccessibility of carotenoids including hardly bioaccessible epoxycarotenoids, finding unaltered rates in pasteurized samples. Bioaccessibility of flavonoids was constant in all cases. Results can promote HPH as an efficient option to obtain health-enhanced foods.


Assuntos
Carotenoides/química , Citrus sinensis/química , Flavonoides/química , Manipulação de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Carotenoides/análise , Cromatografia Líquida de Alta Pressão , Citrus sinensis/metabolismo , Flavonoides/análise , Tamanho da Partícula , Pasteurização , Pressão
16.
Food Chem ; 330: 127261, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32540531

RESUMO

The first detailed phytochemical screening was performed on juices prepared from arils of wild pomegranate fruits taken from several locations in Montenegro with the aim of their future valorization. Particular attention is paid to the effect of pomegranate growth conditions on the juice quality. In addition to the basic parameters of pomegranate fruits and juices, nine primary metabolites (sugars, organic acids and vitamin C) were determined in the juices. Among 97 phenolic compounds, 23 anthocyanins and their derivatives, 33 ellagitannins and derivatives of ellagic acid, 12 flavanols, 4 flavonol glycosides, 1 flavone, 17 hydroxybenzoic acids and 7 hydroxycinnamic acids and their derivatives, were identified. Flavanols (1137-4424 mg/L) as well as ellagitannins and ellagic acid derivatives (1849-2991 mg/L) had the highest concentrations in pomegranate juices. Juices from the pomegranates grown on two soil types had total analyzed phenolics ranging from 4387 mg/L (Eutric Cambisol) up to 8461 mg/L (Terra Rossa).


Assuntos
Sucos de Frutas e Vegetais/análise , Romã (Fruta)/química , Antocianinas/análise , Antioxidantes/química , Frutas/química , Genótipo , Montenegro , Fenóis/análise , Compostos Fitoquímicos/análise , Polifenóis/análise , Romã (Fruta)/genética
17.
Food Chem ; 330: 127227, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32521402

RESUMO

A hydroxycinnamate-like component was identified in highbush blueberry (Vaccinium corymbosum) fruit, which had identical UV and mass spectrometric properties to an S-linked glutathionyl conjugate of chlorogenic acid synthesized using a peroxidase-catalyzed reaction. The conjugate was present in fruits from all highbush blueberry genotypes grown in one season, reaching 7-20% of the relative abundance of 5-caffeoylquininc acid. It was enriched, along with anthocyanins, by fractionation on solid phase cation-exchange units. Mining of pre-existing LC-MS data confirmed that this conjugate was ubiquitous in highbush blueberries, but also present in other Vaccinium species. Similar data mining identified this conjugate in potato tubers with enrichment in peel tissues. In addition, the conjugate was also present in commercial apple juice and was stable to pasteurization and storage. Although glutathionyl conjugates of hydroxycinnamic acids have been noted previously, this is the first report of glutathionyl conjugates of chlorogenic acids in commonly-eaten fruits and vegetables.


Assuntos
Mirtilos Azuis (Planta)/química , Ácido Clorogênico/análise , Sucos de Frutas e Vegetais/análise , Malus/química , Solanum tuberosum/química , Antocianinas/análise , Frutas/química , Tubérculos/química
18.
J Chromatogr A ; 1622: 461119, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32376013

RESUMO

Next to furan, other alkylfurans such as 2- and 3-methylfuran, 2-ethylfuran, 2,5-dimethylfuran, and 2-pentylfuran have been found concurrently in thermal processed food and fruit juices. To ensure an accurate quantification of these compounds, a method based on isotope dilution using all six respective internal standards and gas chromatography coupled to mass spectrometry was developed. Two injection techniques, static head space (HS) and solid phase micro extraction (SPME), were tested and compared for their performance. Validation was based on a single laboratory validation under repeatability condition. Good data for both techniques in baby food and cereals were obtained. Furthermore, validation was conducted successfully on fruit juices and infant formula using SPME injection and on coffee using HS injection. LOQ for all matrices was established at 5 µg/kg and 200 µg/kg in coffee samples, which corresponds to the lowest fortification level. Recovery was between 80 % and 110 % and repeatability obtained below 16 % at 50 µg/kg (7.4 % at 10 mg/kg for coffee samples), except few slight outliers.


Assuntos
Análise de Alimentos/métodos , Furanos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Café/química , Grão Comestível/química , Sucos de Frutas e Vegetais/análise , Humanos , Lactente , Alimentos Infantis/análise , Microextração em Fase Sólida
19.
Food Chem ; 326: 126977, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32447161

RESUMO

Changes in sensorial, chemical and microbiological qualities of kefirs fortified with black carrot (KBCJ), black mulberry (KBMJ), pomegranate (KPJ), and strawberry (KSJ) juices at different concentrations (10, 25 and 50%, w/w) were monitored throughout storage at 4 °C for 12 weeks. The most preferred kefirs by the sensorial panel were KSJ and KPJ, followed by KBMJ and KBCJ. KBMJ was associated with the highest anthocyanin stability, followed by KPJ, KSJ, and KBCJ. Lactic acid [r = (-0.688)-(-0.970)], glucose [r = (-0.563)-(-0.793)] and microorganisms [r = (-0.633)-(-0.961)] in kefirs had significant effect on anthocyanin stability and colour (p < 0.05). Copigmentation between lactic acid and anthocyanins were observed. Fortification with 25% juices led to an increase (1.8-4.8 times) in antioxidant activity (AA). Shelf-lives of samples, except for KPJ, ended after 12 weeks of storage, due to low sensorial scores. Additions of SJ, PJ and BMJ at 25% concentration are recommended for the production of more palatable kefir with high AA.


Assuntos
Antocianinas/química , Armazenamento de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Kefir/análise , Antocianinas/metabolismo , Antioxidantes/química , Temperatura Baixa , Cor , Concentração de Íons de Hidrogênio , Cinética , Ácido Láctico/química
20.
J Food Sci ; 85(6): 1764-1771, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32406938

RESUMO

The novel discovery of p-hydroxyphenylbutan-2-one (berry note) in Riceberry aroma was characterized by gas chromatography-olfactometry and gas chromatography-time-of-flight mass spectrometry. Odor activity values and aroma extract dilution analysis revealed the high potency of this ketone, vanillin, and guaiacol found within the purple rice. Furthermore, ultrapasteurization (UP), high-temperature short-time (HTST) pasteurization, and ultrahigh-temperature (UHT) sterilization effects on rice beverage aroma were analyzed using Riceberry as a sample. Riceberry's key odorants also remained the primary aromatic contributors in beverage models. Although descriptive sensory analysis showed a slightly lower musty note intensity in HTST beverages compared to the UP sample, their flavor dilution chromatograms were similar. Cluster analysis and R-index ranking test further confirmed aroma similarities during storage. Stored samples sterilized via UHT experienced certain potential off-odors, including acetic acid, propanoic acid, and indole, as opposed to the other beverages. UP was therefore superior to HTST and UHT by extending beverage shelf life without any undesirable odors. PRACTICAL APPLICATION: Ultrapasteurization (UP) retains Riceberry aroma characteristic in beverages and requires minimal modifications beyond conventional pasteurization. UP beverages also surpass those of high-temperature short-time and ultrahigh-temperature by extending shelf life with no noticeable off-odors. In addition, the discovery of p-hydroxyphenylbutan-2-one and the other aroma-active compounds of Riceberry aroma should prove valuable for flavor creation, rice breeding, and rice quality standards.


Assuntos
Bebidas/análise , Sucos de Frutas e Vegetais/análise , Oryza/química , Cromatografia Gasosa-Espectrometria de Massas , Temperatura Alta , Humanos , Odorantes/análise , Olfatometria , Pasteurização , Paladar , Temperatura , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química
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