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1.
Molecules ; 26(6)2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33802805

RESUMO

Red mature calyces of Hibiscus sabdariffa were collected from 16 different locations in Meghalaya, India. Samples were processed using shade drying (SD) and tray drying (TD). NMR spectroscopy was used to assess the metabolic composition of the calyces. In this study, 18 polar metabolites were assigned using 1D and 2D NMR spectra, and 10 of them were quantified. Proximate analysis showed that the TD method is more efficient at reducing moisture and maintaining the ash content of the Hibiscus biomass. NMR metabolomics indicates that the metabolite composition significantly differs between SD and TD samples and is more stable in TD plant processing. The differences in post-harvest drying has a greater impact on the metabolite composition of Hibiscus than the plant location.


Assuntos
Dessecação/métodos , Flores/química , Hibiscus/química , Metaboloma , Extratos Vegetais/química , Ácido Acético/análise , Betaína/análise , Citratos/análise , Correlação de Dados , Fumaratos/análise , Índia , Lipídeos/análise , Espectroscopia de Ressonância Magnética , Metabolômica , Metanol/análise , Extratos Vegetais/análise , Análise de Componente Principal , Ácido Succínico/análise , Açúcares/análise , Ácido gama-Aminobutírico/análise
2.
Food Chem ; 354: 129503, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-33743446

RESUMO

As a flavor and quality parameter, furfural has potential undesirable effects. This study aimed to elucidate furfural formation, including generation, pathways, and possible precursors during the production of Zhenjiang aromatic vinegar. A cereal vinegar model, rich in saccharides, amino acids, and organic acids, was used to explore the potential precursors. Furfural and 5-hydroxymethylfurfural (HMF) mainly generated during the decoction process, but the HMF also increased during the aging process. Three pathways were found to coexist for the formation of furfural: (i) the Maillard reaction induced by saccharides and nitrogenous compounds, (ii) the direct cleavage of pentose, and (iii) indirect conversion from pentosan, which only made a minor contribution. Furfural was not formed from HMF or l-ascorbic acid in vinegar. Instead, ribose, xylose, arabinose, galacturonic acid, glucuronic acid, and pentosan were the main precursors. These insights may be useful for the risk/benefit balance and improve the flavor quality and safety.


Assuntos
Ácido Acético/análise , Furaldeído/análise , Aminoácidos/análise , Ácido Ascórbico/análise , Cromatografia Líquida de Alta Pressão/métodos , Furaldeído/análogos & derivados , Furaldeído/química , Espectrofotometria Ultravioleta , Açúcares/análise , Ácidos Urônicos/análise
3.
Food Chem ; 350: 129274, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33610849

RESUMO

A novel functional kombucha using laver was developed by fermentation for 14 d at 25 °C through kombucha consortia of yeast and bacteria. The physicochemical characteristics, antioxidant effects, and nutraceutical properties of laver kombucha from infusion extracts (K-IE) and ultrasound-assisted extracts (K-UAE) were compared with those of black tea (K-BT) and green tea kombucha (K-GT). Tea kombucha showed higher amounts of total phenols and flavonoid content, and ferric reducing antioxidant power (FRAP) while K-UAE exhibited the highest content of organic acid, especially, α- ketoglutaric acid (224.97 mg/100 mL), and acetic acid (564.15 mg/100 mL) with highest titratable acidity, lower pH value and enhanced DPPH scavenging ability. Hence, laver has significant potential to be used as a substrate for developing new fermented beverages through ultrasound-assisted extraction.


Assuntos
Fermentação , Chá de Kombucha/análise , Chá de Kombucha/microbiologia , Porphyra/microbiologia , Ácido Acético/análise , Antioxidantes/análise , Flavonoides/análise , Fenóis/análise
4.
Food Chem ; 346: 128891, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33387833

RESUMO

Free sulfur dioxide and volatile acidity are parameters related to the quality of wines. Traditional methods for their determination are tedious, time consuming and require analysis in decentralized laboratories, therefore corrective actions cannot be applied on time. This may be more complex in aging wine cellars, where hundreds of individual barrels containing almost finished wines should be monitored. To achieve this aim, a portable microanalytical flow system for the simultaneous detection of free SO2 and acetic acid during the ageing of wines is proposed in this work. The miniaturized system is based on the use of a gas-diffusion membrane and a pH-ISFET, and can be easily installed in barrels. The system was optimized in the range of 5-60 mg L-1 and 0.15-1.40 g L-1 for SO2 and acetic acid, respectively. It was validated with different sets of wine samples by comparing the results with standard methods, demonstrating a good agreement between methods.


Assuntos
Ácido Acético/análise , Análise de Alimentos/métodos , Dióxido de Enxofre/análise , Vinho/análise , Difusão , Fatores de Tempo
5.
J Oleo Sci ; 70(1): 31-38, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33431770

RESUMO

The flavor and taste of the foods play an important or even a decisive role in the acceptance and preference of the consumers. It was found that the sesame paste prepared with the germinated sesame seeds was bitter in our previous experiment. In the study, the volatile and non-volatile bitter-taste components of the sesame paste samples were comprehensively analyzed. 2-methylbutanal, hexanal, acetic acid, and butyric acid were the predominant volatile compounds in the soaked and germinated sesame pastes. Oxalate was significantly reduced by the germination (p < 0.05). The contents of sesaminoltriglucoside in sesame pastes ranged from 129.04 to 217.57 µg/g. Both total and individual free amino acid contents increased with the prolongation of the germinating time. The bitter-taste amino acid Arg had the highest score of Taste Activity Value for the bitterest sample made from the seeds germinated for 36 hours. The bitter-tasting Arg was first reported to impart a bitter taste to the germinated sesame paste.


Assuntos
Aldeídos/análise , Comportamento do Consumidor , Análise de Alimentos , Germinação/fisiologia , Pentanóis/análise , Sementes/química , Sesamum/química , Paladar , Ácido Acético/análise , Arginina/análise , Ácido Butírico/análise , Glucosídeos/análise , Oxalatos/análise , Sementes/fisiologia , Sesamum/metabolismo , Sesamum/fisiologia , Fatores de Tempo , Volatilização
6.
J Dairy Sci ; 104(2): 1696-1713, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33309357

RESUMO

The environment temperature and its effect on the temperature of silage is very important for the fermentation and subsequent quality of a silage. Obligate heterofermentative lactic acid bacteria (LAB) inocula, because of their ability to inhibit yeasts, have been developed to prevent the aerobic deterioration of silages. The temperature during silage conservation may also play an important role in the fermentation profile of silages. This study has evaluated the effect of temperature, during the conservation of whole crop corn silage, untreated or treated with different LAB inocula, on the fermentation profile and on the aerobic stability of the silage. Corn was harvested at 42% dry matter and either not treated (control) or treated with Lactobacillus buchneri NCIMB 40788 (LB) at 300,000 cfu/g fresh matter (FM); Lactobacillus hilgardii CNCM I-4785 at 150,000 cfu/g FM (LH150); L. hilgardii CNCM I-4785 at 300,000 cfu/g FM (LH300); or LB+LH at 150,000 cfu/g FM each. In an attempt to experimentally simulate temperature fluctuations in the mass or at the periphery of a silage bunker, corn was conserved in laboratory silos at a constant temperature (20 ± 1°C; MASS) or at lower and variable outdoor temperatures (PERIPH; ranging from 0.5 to 19°C), and the silos were opened after 15, 30, and 100 d of conservation. Lactic acid, acetic acid, and ethanol contents increased in all the silages over the conservation period. The lactic acid content was higher (+10%) in the silages kept at a constant temperature than those conserved at the lower and variable outdoor temperatures. The acetic acid was higher in the treated silages than in the control ones conserved at a constant temperature for 100 d. Moreover, 1,2-propanediol was only detected in the treated silages after at least 30 d at a constant temperature, whereas only traces were detected in the LB+LH treatment for the other temperature conditions. The yeast count decreased during conservation at a slower rate in PERIPH than in MASS and on average reached 2.96 and 4.71 log cfu/g for MASS and PERIPH, respectively, after 100 d of conservation. The highest aerobic stability values were observed for LH300 (191 h) in the MASS silage after 100 d of conservation, whereas the highest aerobic stability was observed in LB+LH (150 h) in the PERIPH silages. After 7 d of air exposure, a pH higher than 4.5 and a higher yeast than 8.0 log cfu/g were detected in all the silages opened after 15 and 30 d of conservation. A pH value close to that of silo opening was detected in the LB, LH150, and LH300 silages conserved under MASS conditions after 100 d, whereas LB+LH was the most effective under PERIPH conditions. The temperature and its fluctuation during conservation of silage in laboratory silos influenced the fermentation, which in turn had an effect on the quality of silage and on the extent of the effect of LAB inocula.


Assuntos
Fermentação/fisiologia , Lactobacillus/metabolismo , Silagem/microbiologia , Temperatura , Zea mays/microbiologia , Ácido Acético/análise , Aerobiose , Animais , Etanol/análise , Laboratórios , Ácido Láctico/análise , Silagem/análise , Leveduras/isolamento & purificação , Zea mays/química , Zea mays/metabolismo
7.
Food Chem ; 340: 127922, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32889211

RESUMO

This study aimed to evaluate the fermentation performance of a mixture of Lactobacillus spp. in cloudy apple juices from nine cultivars. The results showed that cultivar influenced most the properties of the fermented cloudy apple juice. The fermented cloudy apple juices made from Changfu had the highest viable bacterial count and acetic acid contents (6.37 × 108 CFU/mL and 2.67 mg/mL, respectively). It also had higher sensory score, second only to Huaniu. The highest total sugar consumption, utilising fructose, glucose, and sucrose (33.07 mg/mL), was seen with Golden Delicious. Qinguan fermented cloudy apple juice had the highest contents of lactic acid (6.74 mg/mL) and total esters (921.36 µg/L); d-limonene also detected in this fermented cloudy apple juice. Of the nine cultivars examined in this study, Changfu, Qinguan, and Golden Delicious were the most suitable for producing fermented cloudy apple juice with better taste, higher viable count and more intense aroma.


Assuntos
Alimentos e Bebidas Fermentados/microbiologia , Sucos de Frutas e Vegetais/análise , Sucos de Frutas e Vegetais/microbiologia , Malus , Ácido Acético/análise , Carga Bacteriana , Feminino , Fermentação , Alimentos e Bebidas Fermentados/análise , Humanos , Lactobacillus acidophilus , Lactobacillus fermentum , Lactobacillus plantarum , Masculino , Odorantes/análise , Açúcares/análise , Paladar , Compostos Orgânicos Voláteis/análise
8.
J Oleo Sci ; 69(7): 767-770, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32522942

RESUMO

The volatile components produced by Leptolejeunea elliptica (Lejeuneaceae), which is a liverwort grown on the leaves of tea (Camellia sinensis), were collected and analyzed using headspace solid-phase microextraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS). 1-Ethyl-4-methoxybenzene (1), 1-ethyl-4-hydroxybenzene (2), and 1-acetoxy-4-ethylbenzene (3) were identified as the major components together with several other phenolic compounds, including 1,2-dimethoxy-4-ethylbenzene, and 4-ethylguaiacol in addition to sesquiterpene hydrocarbons, such as α-selinene, ß-selinene, ß-elemene, and ß-caryophyllene. GC/Olfactometry showed the presence of linalool, acetic acid, isovaleric acid, trans-methyl cinnamate, and trans-4,5-epoxy-(2E)-decenal, as the volatile components produced by L. elliptica.


Assuntos
Hepatófitas/metabolismo , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/isolamento & purificação , Ácido Acético/análise , Ácido Acético/isolamento & purificação , Anisóis/análise , Anisóis/isolamento & purificação , Derivados de Benzeno/análise , Derivados de Benzeno/isolamento & purificação , Camellia sinensis , Cromatografia Gasosa-Espectrometria de Massas/métodos , Japão , Olfatometria , Fenol/análise , Fenol/isolamento & purificação , Fenóis/análise , Fenóis/isolamento & purificação , Sesquiterpenos Policíclicos/análise , Sesquiterpenos Policíclicos/isolamento & purificação , Sesquiterpenos/análise , Sesquiterpenos/isolamento & purificação , Microextração em Fase Sólida/métodos
9.
Int J Food Microbiol ; 324: 108615, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32371236

RESUMO

In recent years, CRISPR/Cas9-based genetic editing has become a mainstay in many laboratories including manipulations done with yeast. We utilized this technique to generate a self-cloned wine yeast strain that overexpresses two genes of oenological relevance i.e. the glycerol-3-phosphate dehydrogenase 1 (GPD1) and the alcohol acetyltransferase 1 (ATF1) directly implicated in glycerol and acetate ester production respectively. Riesling wine made from the resulting strain showed increased glycerol and acetate ester levels compared to the parental strain. In addition, significantly less acetic acid levels were measured in wine made with yeast containing both genetic alterations compared to wine made with the strain that only overexpresses GPD1. Thus, this strain provides an alternative strategy for alleviating the accumulation of acetic acid once glycerol production is favoured during alcoholic fermentation with the addition of dramatically increasing acetate esters production.


Assuntos
Sistemas CRISPR-Cas , Saccharomyces cerevisiae/genética , Vinho/microbiologia , Ácido Acético/análise , Ácido Acético/metabolismo , Fermentação , Edição de Genes , Glicerol/análise , Glicerol/metabolismo , Glicerol-3-Fosfato Desidrogenase (NAD+)/genética , Glicerol-3-Fosfato Desidrogenase (NAD+)/metabolismo , Fenótipo , Proteínas/genética , Proteínas/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Vinho/análise
10.
J Strength Cond Res ; 34(6): 1539-1546, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32459412

RESUMO

Marosek, SEH, Antharam, V, and Dowlatshahi, K. Quantitative analysis of the acetic acid content in substances used by athletes for the possible prevention and alleviation of exercise-associated muscle cramps. J Strength Cond Res 34(6): 1539-1546, 2020-Athletes regularly consume commercially available food and sports shot products, carbohydrate beverages, and water to improve their physical exertion and to possibly prevent or relieve exercise-associated muscle cramps (EAMCs)-often experienced during practice, training, or competition. Acetic acid, a component of interest within these products, has been recognized for its potential role in cramp reduction. Acetic acid is postulated to mitigate cramping by decreasing alpha motor neuron activity through oropharyngeal stimulation and inhibitory neurotransmitter production, while aiding in the role acetylcholine plays in muscle contraction and relaxation. The purpose of this research is to analytically assess the most viable sources of acetic acid from substances that athletes ingest before or when experiencing these cramps. The range of samples investigated were based on their widespread use in the athletic world: dill and sweet pickle juices, yellow mustard, sweet relish, apple cider vinegar, Hot Shot, PJ Shot, PJ Sport, E-Lyte Sport, Powerade, Gatorade, Smartwater, and Propel (with electrolytes). As hypothesized, pH and enzymatic assay or spectroscopic analyses revealed that yellow mustard, sweet relish, all pickle juices, and the pickle juice products were composed of moderate amounts of acetic acid. Based on established studies resulting in EAMC relief, acetic acid consumption, and the appropriate serving size, the yellow mustard, PJ Shot, and all pickle juices would be the most practical and palatable sources of acetic acid for strength and conditioning professionals to recommend that athletes consume for the possible prevention or alleviation of muscle cramps.


Assuntos
Ácido Acético/análise , Bebidas , Condimentos , Soluções Isotônicas , Cãibra Muscular/prevenção & controle , Exercício Físico , Humanos , Cãibra Muscular/etiologia
11.
Anim Sci J ; 91(1): e13364, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32219952

RESUMO

To effectively use local available grass resources to cover the winter feed shortage on the Qinghai-Tibetan Plateau, direct-cut and wilted reed canary grass (RCG) silages were prepared by using a rolled-bale system, and their ensiling characteristics and in vitro digestibility were studied. Silages were treated without (control) or with inoculants including LP (Lactobacillus plantarum), LPLB (L. plantarum, L. buchneri), and LPLBc (L. plantarum, L. buchneri, and cellulase), and were stored at ambient temperature (5.7-14.6°C) for 90 days. Compared with control, the inoculated silages increased (p < .05) lactic acid and acetic acid contents, and reduced (p < .05) final pH value and ammonia-N ratio of total N. The highest WSC content (41.2 g/kg DM) occurred for LPLB-inoculated silage, whereas LPLBc-treated silage displayed the lowest contents of NDF (522.9 g/kg DM) and ADF (275.5 g/kg DM). In addition, LPLBc-inoculated silage had the highest in vitro gas production (51.0 ml/g DM), in vitro DM digestibility (619.3 g/kg DM), and metabolic energy (9.6 kJ/kg DM). These results confirmed that treatments with inoculants at ensiling could improve silage fermentation and in vitro digestibility of RCG, and this could be a potential winter feed for animals on the Qinghai-Tibetan Plateau.


Assuntos
Celulase , Digestão , Fermentação , Armazenamento de Alimentos/métodos , Lactobacillus plantarum , Lactobacillus , Phalaris , Silagem , Ácido Acético/análise , Amônia/análise , Metabolismo Energético , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Ácido Láctico/análise , Nitrogênio/análise , Silagem/análise , Temperatura , Tibet , Fatores de Tempo
12.
J Food Sci ; 85(4): 910-917, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32198767

RESUMO

The pH of most acid food products depends on undefined and complex buffering of ingredients but is critically important for regulatory purposes and food safety. Our objective was to define the buffer capacity (BC) of ingredients in salad dressing products. Ingredients of salad dressings were titrated individually and in combination using concentrations typical of dressing products. Titration curves from pH 2 to 12 were generated with sodium hydroxide and hydrochloric acid, which were then used to generate BC curves. A matrix of concentration and pK values for a series of monoprotic buffers approximated the pH of each ingredient. Some buffer series required anion or cation corrections for accurate pH prediction, possibly due to the presence of salts of acid or bases. Most buffers had BC values less than 10-fold the BC of acetic acid (0.25 ß) typically in dressing formulations and had little influence on the final product pH of the dressings tested. Unexpectedly, we found that sugars in dressing formulations, including sucrose or corn syrup, exhibited buffering at pH values greater than 11 (0.035 ß and 0.059 ß, respectively), which was likely due to weakly acidic hydroxyl groups on the sugar molecules. However, the concentration and pK for buffers above pH 11 or below pH 2 were difficult to quantify due to the BC of water. The BC data may help to quantify the effects of salad dressing ingredients on the final product pH and benefit regulatory agencies and manufacturers in assessing product pH and safety. PRACTICAL APPLICATION: Buffer capacity data for salad dressing ingredients may help determine the influence ingredient addition will have on the final pH of a salad dressing product. The addition of low acid ingredients with little or no buffering may not significantly alter pH. The modeling method may be useful for regulatory purposes to estimate the effects of low acid ingredients on pH changes for food safety and may also be useful for product development of acid and acidified foods.


Assuntos
Condimentos/análise , Ingredientes de Alimentos/análise , Ácido Acético/análise , Tampões (Química) , Concentração de Íons de Hidrogênio , Sais/análise
13.
Int J Food Microbiol ; 321: 108551, 2020 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-32078867

RESUMO

Sourdough is a very interesting natural preservation system to prolong mould free shelf-life of bread. Numerous studies have reported that the antifungal activity of sourdough is mainly correlated with the presence of lactic (LA) and acetic acid (AA), but very few information is available on the effect of undissociated acid concentrations in the aqueous phase of bread (CHA; mmole/L). This study was conducted to provide additional information about the mode of action of the acids in sourdough bread, enabling a better shelf-life prediction. This study was divided into two parts. In part 1, three industrial biological sourdoughs were characterized (dough yield, pH, aw, fermentation quotient, microbiota). During 7 weeks, a shelf-life test with natural flora was conducted with daily checks of visible mould growth (21 °C). In part 2, the effect of the acids present in the antifungal active sourdough breads was validated in chemically acidified wheat breads. Complete growth inhibition was observed in full-baked sourdough bread (30 g/100 g dough) containing Lactobacillus sanfranciscensis and Saccharomyces cerevisiae as dominant sourdough micro-organisms, whereas in control bread the shelf-life was limited to 4.4-9.2 days. These full-baked sourdough breads contained 36 mmole undissociated LA/L and 220 mmole undissociated AA/L. The data were used to make General Linear Regression models for shelf-life prediction and resulted in a fit of R2 = 0.79 when expressing the shelf-life in function of CHA,LA and CHA,AA. In acidified breads, the role of lactic acid was not significant and only impacted shelf-life indirectly through acidification. No difference between antifungal activity of sourdough breads and chemically acidified bread with comparable CHA,AA concentrations was observed. Shelf-life increased when 150-200 mmole undissociated AA/L aqueous phase in bread was present. To conclude, this study showed the importance of the undissociated acid fraction of acetic acid in relation to bread shelf-life, together with bread pH and moisture content.


Assuntos
Ácido Acético/farmacologia , Antifúngicos/farmacologia , Pão/análise , Conservação de Alimentos/métodos , Ácido Láctico/farmacologia , Ácido Acético/análise , Antifúngicos/análise , Pão/microbiologia , Fermentação , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Ácido Láctico/análise , Lactobacillus/efeitos dos fármacos , Lactobacillus/crescimento & desenvolvimento , Triticum/microbiologia , Água/análise
14.
Food Chem ; 317: 126424, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32088405

RESUMO

In this study, a simple, efficient, and green effervescence tablet-assisted microextraction method based on the solidification of deep eutectic solvent (ETA-ME-SDES) was developed to determine picoxystrobin, pyraclostrobin, and trifloxystrobin in water, juice, wine, and vinegar samples by HPLC. An eco-friendly, hydrophobic, deep eutectic solvent (DES, acting as the extraction solvent) was synthesized by thymol and octanoic acid in the molar ratio of 1:5. The extraction solvent dispersed in sample solutions with the assistance of pH adjustment and effervescence reaction, and was collected after solidification in an ice bath. Several essential conditions, including the type and the volume of DESs, the amount of ammonia hydroxide, and the components of effervescence tablets were optimized. The limits of detection ranged from 0.15 to 0.38 µg L-1. Extraction recovery ranged from 77.4 to 106.9%. The proposed method was successful in determining the amount of strobilurin fungicides in water, juice, wine, and vinegar samples.


Assuntos
Ácido Acético/análise , Cromatografia Líquida de Alta Pressão , Sucos de Frutas e Vegetais/análise , Fungicidas Industriais/análise , Estrobilurinas/análise , Poluentes Químicos da Água/análise , Vinho/análise , Acetatos/análise , Fungicidas Industriais/química , Concentração de Íons de Hidrogênio , Iminas/análise , Limite de Detecção , Microextração em Fase Líquida/métodos , Sais/química , Estrobilurinas/química , Poluentes Químicos da Água/química
15.
Sci Rep ; 10(1): 697, 2020 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-31959821

RESUMO

Pellicle is the initial proteinaceous layer that is formed almost instantaneously on all solid surfaces in the oral cavity. It is of essential relevance for any interactions and metabolism on the tooth surface. Up to now, there is no information on the metabolome of this structure. Accordingly, the present study aims to characterise the metabolomic profile of in-situ pellicle in children with different caries activity for the first time in comparison to saliva. Small molecules such as carbohydrates, amino acids, organic acids, and fatty acids, putatively involved in the formation of caries were quantified using mass spectrometry (MS)-based techniques, such as (stable isotope dilution analysis)-ultra-performance liquid chromatography-tandem MS and gas chromatography/electron ionisation-MS. Pellicle and corresponding saliva samples were collected from caries-active, caries-free and caries-rehabilitated 4- to 6-year-old children. The most abundant analytes in pellicle were acetic acid (1.2-10.5 nmol/cm2), propionic acid (0.1-8.5 nmol/cm2), glycine (0.7-3.5 nmol/cm2), serine (0.08-2.3 nmol/cm2), galactose (galactose + mannose; 0.035-0.078 nmol/cm2), lactose (0.002-0.086 nmol/cm2), glucose (0.018-0.953 nmol/cm2), palmitic acid (0.26-2.03 nmol/cm2), and stearic acid (0.34-1.81 nmol/cm2). Significant differences depending on caries activity were detected neither in saliva nor in the corresponding pellicle samples.


Assuntos
Cárie Dentária/metabolismo , Película Dentária/química , Metabolômica/métodos , Saliva/química , Ácido Acético/análise , Estudos de Casos e Controles , Criança , Pré-Escolar , Cromatografia Líquida , Glicina/análise , Humanos , Masculino , Propionatos/análise , Espectrometria de Massas em Tandem
16.
J Sci Food Agric ; 100(5): 2198-2207, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31901138

RESUMO

BACKGROUND: Honey has a very important commercial value for producers as a natural product. Honey aroma is formed from the contributions of several volatile compounds, which are influenced by nectar composition, botanical origins, and location. Selected-ion flow-tube mass spectrometry (SIFT-MS) is a technique that quantifies volatile organic compounds simply and rapidly, even in low concentrations. In this study, the headspace concentration of eight monofloral (chestnut, rhododendron, lavender, sage, carob, heather, citrus, and pine) and three multiflower Turkish honeys were analyzed using SIFT-MS. Soft independent modeling of class analogy (SIMCA) was used to differentiate honey samples based on their volatiles. RESULTS: This study focused on 78 volatile compounds, which were selected from previous studies of selected honeys. Very clear distinctions were observed between all honeys. Interclass distances greater than 8 indicate that honeys were significantly different. Methanol and ethanol were abundant in the honeys. Chestnut honey collected from the Yalova region had the highest total concentration of volatiles followed by heather honey and chestnut honey collected from the Düzce region. CONCLUSION: Honeys with different botanical and geographical origins showed differences in their volatile profile based on chemometric analysis. Of the honey samples, methanol, ethanol, acetoin, ethyl acetate, and isobutanoic acid had the highest discriminating power. Methanol and ethanol, and then acetic acid, were the volatiles with the highest concentrations in most honeys. © 2020 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Geografia , Mel/análise , Compostos Orgânicos Voláteis/análise , Acetatos/análise , Ácido Acético/análise , Etanol/análise , Flores/química , Cromatografia Gasosa-Espectrometria de Massas , Espectrometria de Massas , Metanol/análise , Análise Multivariada , Odorantes/análise , Turquia
17.
Int J Food Microbiol ; 318: 108465, 2020 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-31838279

RESUMO

Cupuassu (Theobroma grandiflorum Schum) is a fruit belonging to the same genus as cocoa and, through seed fermentation, a chocolate-like product called "the cupulate" is obtained. The pulp is removed from the seeds before fermentation because its abundance hinders the process. Unlike cocoa, little is known about the microbial diversity involved in cupuassu fermentation. The goal of this study was to explore the use of next-generation sequencing to identify the yeasts and bacteria communities involved in cupuassu seed fermentation on three different pulp concentrations (0, 7.5, and 15%) as well as two turning schemes on the microbial growth. In order to do that, a massive sequencing of the 16S and ITS4 rRNA region (S) using the Illumina MiSeq Platform identified some genera of bacteria and yeasts, respectively, in the fermentation environment. Taxonomic analyses of both communities, especially at the genus level, revealed a predominance of yeasts such as Pichia and Hanseniaspora, and bacteria such as Acetobacter and Lactobacillus. A predominance of bacteria over yeasts diversity was observed in the experiments with higher pulp concentrations (15%). The physicochemical analysis showed that fermentation of samples with 15% pulp exhibited longer fermentation times, the highest temperatures, and elevated production of organic acids such as acetic acid, a precursor of flavor. In addition, the turning applied every 24 h to the mass slightly favored the formation of flavor precursors. It seems that the abundance and composition of cupuassu pulp, rich in organic compounds, can influence the diversity of some populations of yeasts. Some of those compounds identified in previous studies are terpenes with antimicrobial activity. More studies will be necessary to confirm if the presence of terpenes compounds in the cupuassu pulp exert some inhibitory action on microorganism diversity.


Assuntos
Cacau/microbiologia , Alimentos e Bebidas Fermentados/microbiologia , Microbiota , Ácido Acético/análise , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Fermentação , Frutas/microbiologia , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Fungos/metabolismo , Microbiota/genética , Sementes/microbiologia , Paladar
18.
Braz J Microbiol ; 51(1): 323-334, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31788756

RESUMO

The use of appropriate yeast strains allows to better control the fermentation during beverage production. Bee products, especially of stingless bees, are poorly explored as sources of fermenting microorganisms. In this work, yeasts were isolated from honey and pollen from Tetragonisca angustula (Jataí), Nannotrigona testaceicornis (Iraí), Frieseomelitta varia (Marmelada), and honey of Apis mellifera bees and screened according to morphology, growth, and alcohol production. Bee products showed to be potential sources of fermenting microorganisms. From 55 isolates, one was identified as Papiliotrema flavescens, two Rhodotorula mucilaginosa, five Saccharomyces cerevisiae, and nine Starmerella meliponinorum. The S. cerevisiae strains were able to produce ethanol and glycerol at pH 4.0-8.0 and temperature of 10-30 °C, with low or none production of undesirable compounds, such as acetic acid and methanol. These strains are suitable for the production of bioethanol and alcoholic beverages due to their high ethanol production, similar or superior to the commercial strain, and in a broad range of conditions like as 50% (m/v) glucose, 10% (v/v) ethanol, or 500 mg L-1 of sodium metabisulfite.


Assuntos
Bebidas Alcoólicas/microbiologia , Mel/microbiologia , Pólen/microbiologia , Leveduras/isolamento & purificação , Ácido Acético/análise , Ácido Acético/metabolismo , Animais , Abelhas , DNA Espaçador Ribossômico , Etanol/análise , Etanol/metabolismo , Fermentação , Genes Fúngicos , Glicerol/análise , Glicerol/metabolismo , Rhodotorula/genética , Rhodotorula/isolamento & purificação , Rhodotorula/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/isolamento & purificação , Saccharomyces cerevisiae/metabolismo , Leveduras/genética , Leveduras/metabolismo
19.
Food Chem ; 311: 126012, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31855771

RESUMO

The aroma profiles of Spanish wine vinegars with Protected Designation of Origin (PDO) were described and compared for the first time by gas chromatography-mass spectrometry-olfactometry (GC-MS-O), odor-active values (OAVs) and quantitative descriptive analysis (QDA). Vinagre de Jerez Reserva (JRE) showed higher percentage of 'grassy-vegetal' impact odorants, while 'spicy' compounds highlighted the Pedro Ximénez category (JPX). Vinagre de Montilla-Moriles Reserva (MRE) had 'buttery-lactic' impact odorants, while 'empyreumatic' and 'sweet' aromas stood out for Pedro Ximénez category (MPX). Vinagre de Condado de Huelva Reserva (CRE) showed a stronger percentage of 'chemical' impact odorants. The key odorants were ethyl propionate, ethyl octanoate, propanoic acid and 4-ethylphenol for JRE, diacetyl and methional/furfural for JPX, acetoin for MRE, ethyl phenylacetate and vanillin for MPX and acetaldehyde diethyl acetal, isobutyl acetate, ethyl isovalerate and guaiacol for CRE. A good relation among the impact odorants and the sensory descriptors was observed.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Odorantes/análise , Compostos Orgânicos Voláteis/análise , Vinho/análise , Ácido Acético/análise , Feminino , Humanos , Masculino , Olfatometria , Análise de Componente Principal , Paladar
20.
J Dairy Sci ; 103(1): 215-219, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31733842

RESUMO

Kefir is an artisanal product that is gaining scientific attention due to its increase in consumption attributed to its potential health benefits. The effect on the quality attributes of kefir grains of different origin (household and commercial) and preserved with different methods (drying and freezing) was evaluated to standardize a domestic and semi-industrial process. Chemical (protein, lactose. lactic acid, ethanol, and acetic acid) as well as microbial properties (total plate count and total yeast count) were monitored during the experiment. Results show a statistical difference between the kefir grains in terms of acetic acid and ethanol percentages, which leads to the conclusion that there is a difference in the microbial populations that produce these products. Lactic acid, protein, and lactose parameters are statistically the same as well as the growth in biomass and the total population of yeast. Our results suggest that both types of kefir grains maintain a similar performance and that their metabolic capabilities are stable throughout time (taking into account that the household grains have been productive for years), meaning that domestic or semi-industrial processes could be easily standardized.


Assuntos
Ácido Acético/análise , Etanol/análise , Kefir/análise , Animais , Costa Rica , Fermentação
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