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1.
ACS Omega ; 8(49): 46804-46815, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-38107938

RESUMO

Here, we explore a catalyst-free single-step growth strategy that results in high-quality self-assembled single-crystal vertical GaN nanowires (NWs) grown on a wide range of common and novel substrates (including GaN, Ga2O3, and monolayer two-dimensional (2D) transition-metal dichalcogenide (TMD)) within the same chamber and thus under identical conditions by pulsed laser deposition. High-resolution transmission electron microscopy and scanning transmission electron microscopy (HR-STEM) and grazing incidence X-ray diffraction measurements confirm the single-crystalline nature of the obtained NWs, whereas advanced optical and cathodoluminescence measurements provide evidence of their high optical quality. Further analyses reveal that the growth is initiated by an in situ polycrystalline layer formed between the NWs and substrates during growth, while as its thickness increases, the growth mode transforms into single-crystalline NW nucleation. HR-STEM and corresponding energy-dispersive X-ray compositional analyses indicate possible growth mechanisms. All samples exhibit strong band edge UV emission (with a negligible defect band) dominated by radiative recombination with a high optical efficiency (∼65%). As all NWs have similar structural and optical qualities irrespective of the substrate used, this strategy will open new horizons for developing III-nitride-based devices.

2.
Foods ; 12(19)2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37835314

RESUMO

Leaf removal is a cultural practice mainly aimed at improving cluster zone microclimates and impacting primary and secondary metabolites, such as volatiles. This research aimed to assess the impact of defoliation on free and glycosylated aromas of a neutral ('Nebbiolo') and a semi-aromatic ('Aleatico') red variety. Defoliation was performed at fruit set (BBCH 71) and, for 'Nebbiolo', also at berries touch (BBCH 81) phenological stages. Skins and pulps were separately analyzed by Solid Phase Extraction-Gas Chromatography/Mass Spectrometry. Results showed that the response to defoliation was variety-dependent. For 'Nebbiolo', especially when performed at the berries' touch stage, defoliation had a significant effect on the accumulation of free volatiles and glycosidic precursors. Differently, free and bound 'Aleatico' volatiles were less impacted by defoliation. Interestingly, in both grapevine varieties, defoliation significantly enhanced the accumulation of aroma precursors in grapes' skins, which is of particular relevance for red wine production and their aging potential. Moreover, results could be helpful for the management of grape quality, as defoliation is currently considered as a strategy to address climate change issues.

3.
Acta Neuropathol ; 145(3): 335-355, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36695896

RESUMO

B cells contribute to the pathogenesis of both cellular- and humoral-mediated central nervous system (CNS) inflammatory diseases through a variety of mechanisms. In such conditions, B cells may enter the CNS parenchyma and contribute to local tissue destruction. It remains unexplored, however, how infection and autoimmunity drive transcriptional phenotypes, repertoire features, and antibody functionality. Here, we profiled B cells from the CNS of murine models of intracranial (i.c.) viral infections and autoimmunity. We identified a population of clonally expanded, antibody-secreting cells (ASCs) that had undergone class-switch recombination and extensive somatic hypermutation following i.c. infection with attenuated lymphocytic choriomeningitis virus (rLCMV). Recombinant expression and characterisation of these antibodies revealed specificity to viral antigens (LCMV glycoprotein GP), correlating with ASC persistence in the brain weeks after resolved infection. Furthermore, these virus-specific ASCs upregulated proliferation and expansion programs in response to the conditional and transient induction of the LCMV GP as a neo-self antigen by astrocytes. This class-switched, clonally expanded, and mutated population persisted and was even more pronounced when peripheral B cells were depleted prior to autoantigen induction in the CNS. In contrast, the most expanded B cell clones in mice with persistent expression of LCMV GP in the CNS did not exhibit neo-self antigen specificity, potentially a consequence of local tolerance induction. Finally, a comparable population of clonally expanded, class-switched, and proliferating ASCs was detected in the cerebrospinal fluid of relapsing multiple sclerosis (RMS) patients. Taken together, our findings support the existence of B cells that populate the CNS and are capable of responding to locally encountered autoantigens.


Assuntos
Células Produtoras de Anticorpos , Autoantígenos , Camundongos , Animais , Linfócitos B , Vírus da Coriomeningite Linfocítica , Encéfalo
4.
Molecules ; 27(22)2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36432200

RESUMO

'Oliva di Gaeta' is almost certainly the most important and well-known PDO denomination for table olives in Italy. Their production is based on a specific two-stage trade preparation called the 'Itrana' method. In this work, we investigated how variations in the duration of the initial water fermentation (i.e., 15 and 30 days) and the salt concentration (i.e., 6% and 8% NaCl) influence the chemical features, microbial dynamics, polyphenols, volatile organic compounds, and sensory features of 'Oliva di Gaeta'. The time of the addition of salt did not affect the final concentration in the brine, but a longer initial water fermentation (before salt addition) led to lower pH values. The bacterial count constantly increased until the salt addition (i.e., either 15 or 30 days), while the yeast population peaked on day 30. Generally, the two different salt concentrations did not affect the count of microorganisms at the end of fermentation, with the only exception being a higher lactic acid bacteria count for the treatment with 6% salt added at 30 days. At commercial maturity, the crucial bitter tastant oleuropein was not completely removed from the drupes, and differences in salt concentration and the length of the first-stage water fermentation did not influence its content at the end of olive curing. Richer volatile profiles of olives were detected with higher-salt treatments, while the combination of low salt and early saline treatment provided a more distinct profile. Longer initial water fermentation caused a small increase in some phenolic compounds (e.g., iso-verbascoside, verbascoside, and hydroxytyrosol-glucoside). A panel test indicated that salt application at 30 days resulted in a more "Sour" and "Bitter" taste, irrespective of the salt concentration. The low salt concentration coupled with the late saline treatment resulted in more "Fruity" notes, probably due to the higher production of esters by lactobacilli. The slightly bitter perception of the olives was consistent with the partial removal of oleuropein. Our work revealed the characteristics of the 'Itrana' method and that the variation in salt concentration and its time of application changes parameters ranging from the microbial dynamics to the sensory profile. Specifically, our data indicate that 6% NaCl coupled with a longer initial water fermentation is the most different condition: it is less effective in blocking microbial growth but, at the same time, is more potent in altering the nutritional (e.g., polyphenols) and sensorial qualities (e.g., bitterness and fruitiness) of 'Oliva di Gaeta'.


Assuntos
Olea , Compostos Orgânicos Voláteis , Olea/química , Fermentação , Cloreto de Sódio , Microbiologia de Alimentos , Cloreto de Sódio na Dieta , Polifenóis , Água
5.
Food Res Int ; 161: 111858, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36192980

RESUMO

The increased interest in foods which improve human health and nutrition has led to the need for academia and food industry to invest in the development of innovative and functional ice cream. Since ice cream is the most popular frozen dairy product, it shows good potential to help people improve their diets by reducing the intake of certain nutrients associated with the increased risk of obesity and other related diseases. Moreover, it supplies beneficial and essential components. However, the reduction or removal of common ice cream ingredients or the addition of uncommon ingredients to the standard formulation must not spoil the sensory characteristics and storage stability of ice cream. Hence, to keep the appeal of ice cream high, the food industry is subjected to constant challenges, since functional ice cream must be tasty as well as beneficial. The review focuses on the healthy aspects and sensory implications of ice cream functionalization. In the first part, different replacing strategies such as the substitution of fat and sugar are discussed. In the second part, ice cream enriched with functional ingredients is debated.


Assuntos
Sorvetes , Laticínios , Manipulação de Alimentos , Humanos , Sorvetes/análise , Açúcares , Paladar
6.
J Am Chem Soc ; 144(29): 13302-13310, 2022 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-35834433

RESUMO

Bright-red light-emitting diodes (LEDs) with a narrow emission line width that emit between 620 and 635 nm are needed to meet the latest industry color standard for wide color gamut displays, Rec. 2020. CsPbI3 perovskite quantum dots (QDs) are one of the few known materials that are ideally suited to meet these criteria. Unfortunately, CsPbI3 perovskite QDs are prone to transform into a non-red-emitting phase and are subject to further degradation mechanisms when their luminescence wavelength is tuned to match that of the Rec. 2020 standard. Here, we show that zwitterionic lecithin ligands can stabilize the perovskite phase of CsPbI3 QDs for long periods in air for at least 6 months compared to a few days for control samples. LEDs fabricated with our ultrastable lecithin-capped CsPbI3 QDs exhibit an external quantum efficiency (EQE) of 7.1% for electroluminescence centered at 634 nm─a record for all-inorganic perovskite nanocrystals in Rec. 2020 red. Our devices achieve a maximum luminance of 1391 cd/m2 at 7.5 V, and their operational half-life is 33 min (T50) at 200 cd/m2─a 10-fold enhancement compared to control samples. Density functional theory results suggest that the surface strain in CsPbI3 QDs capped with the conventional ligands, oleic acid and oleylamine, contributes to the instability of the perovskite structural phase. On the other hand, lecithin binding induces virtually no surface strain and shows a stronger binding tendency for the CsPbI3 surface. Our study highlights the tremendous potential of zwitterionic ligands in stabilizing the perovskite phase and particle size of CsPbI3 QDs for various optoelectronic applications.

7.
Eur J Immunol ; 52(2): 297-311, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34727578

RESUMO

Plasma cells and their secreted antibodies play a central role in the long-term protection against chronic viral infection. However, due to experimental limitations, a comprehensive description of linked genotypic, phenotypic, and antibody repertoire features of plasma cells (gene expression, clonal frequency, virus specificity, and affinity) has been challenging to obtain. To address this, we performed single-cell transcriptome and antibody repertoire sequencing of the murine BM plasma cell population following chronic lymphocytic choriomeningitis virus infection. Our single-cell sequencing approach recovered full-length and paired heavy- and light-chain sequence information for thousands of plasma cells and enabled us to perform recombinant antibody expression and specificity screening. Antibody repertoire analysis revealed that, relative to protein immunization, chronic infection led to increased levels of clonal expansion, class-switching, and somatic variants. Furthermore, antibodies from the highly expanded and class-switched (IgG) plasma cells were found to be specific for multiple viral antigens and a subset of clones exhibited cross-reactivity to nonviral and autoantigens. Integrating single-cell transcriptome data with antibody specificity suggested that plasma cell transcriptional phenotype was correlated to viral antigen specificity. Our findings demonstrate that chronic viral infection can induce and sustain plasma cell clonal expansion, combined with significant somatic hypermutation, and can generate cross-reactive antibodies.


Assuntos
Anticorpos Antivirais , Seleção Clonal Mediada por Antígeno , Cadeias Pesadas de Imunoglobulinas , Cadeias Leves de Imunoglobulina , Coriomeningite Linfocítica , Vírus da Coriomeningite Linfocítica/imunologia , Plasmócitos/imunologia , Análise de Célula Única , Animais , Anticorpos Antivirais/genética , Anticorpos Antivirais/imunologia , Doença Crônica , Feminino , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Pesadas de Imunoglobulinas/imunologia , Cadeias Leves de Imunoglobulina/genética , Cadeias Leves de Imunoglobulina/imunologia , Coriomeningite Linfocítica/genética , Coriomeningite Linfocítica/imunologia , Camundongos
8.
Food Chem ; 361: 130037, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34029909

RESUMO

In this study, the concentration of furan and 2-methylfuran in espresso coffee (EC) obtained from Arabica and Robusta coffee varieties was determined as a function of specific particle size. The particle size and coffee variety significantly influenced the level of furan and 2-methylfuran. In Arabica variety, furan and 2-methylfuran level increased with increasing particle size. Particularly, from C<200µm to C>425µm fractions, furan increased from 68.27 to 91.48 ng mL-1 while 2-methylfuran from 404.31 to 634.64 ng mL-1. In Robusta variety, the highest concentration of furan and 2-methylfuran occurred in ECs prepared using C300-425µm fraction showing values of 116.39 ng mL-1 and 845.14 ng mL-1, respectively, for furan and 2-methylfuran. On the basis of this experiment, it is possible to establish a mitigation strategy by manipulating the particle size and coffee variety in order to reduce the level of furan and 2-methylfuran in EC up to 11.4% and 18.8%, respectively.


Assuntos
Café/química , Furanos/análise , Inocuidade dos Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Tamanho da Partícula
9.
NPJ Sci Food ; 4(1): 19, 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-33298959

RESUMO

Using a range of chromatographic, spectroscopic, and mass spectrometric analytical techniques, we characterized one of the "edible items" found at the Vesuvius archeological sites and guarded at the National Archaeological Museum of Naples (MANN) in Naples, Italy. We authenticated the specimen contained in a glass bottle (Mann-S1 sample) as originally olive oil and mapped the deep evolution throughout its 2000 years of storage. Triacylglycerols were completely hydrolyzed, while the resulting (hydroxy) fatty acids had partly condensed into rarely found estolides. A complex pattern of volatile compounds arose mainly from breakdown of oleic acid. With excellent approximation, radiocarbon dating placed the find at the time of the Plinian Mount Vesuvius eruption in 79 A.D., indicating that Mann-S1 is probably the oldest residue of olive oil in the world found in bulk amount (nearly 0.7 L).

10.
Sci Rep ; 10(1): 18931, 2020 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-33116274

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

11.
Sci Rep ; 10(1): 14703, 2020 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-32895394

RESUMO

Nanorange thickness graphite films (NGFs) are robust nanomaterials that can be produced via catalytic chemical vapour deposition but questions remain regarding their facile transfer and how surface topography may affect their application in next-generation devices. Here, we report the growth of NGFs (with an area of 55 cm2 and thickness of ~ 100 nm) on both sides of a polycrystalline Ni foil and their polymer-free transfer (front- and back-side, in areas up to 6 cm2). Due to the catalyst foil topography, the two carbon films differed in physical properties and other characteristics such as surface roughness. We demonstrate that the coarser back-side NGF is well-suited for NO2 sensing, whereas the smoother and more electrically conductive front-side NGF (2000 S/cm, sheet resistance - 50 Ω/sq) could be a viable conducting channel or counter electrode in solar cells (as it transmits 62% of visible light). Overall, the growth and transfer processes described could help realizing NGFs as an alternative carbon material for those technological applications where graphene and micrometer-thick graphite films are not an option.

12.
Nanotechnology ; 31(48): 485605, 2020 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-32679579

RESUMO

The growth of graphite on polycrystalline Ni by chemical vapor deposition (CVD) and the microstructural relation of the graphitic films and the metallic substrate continues to puzzle the scientific community. Here, we report the wafer-scale growth of a nanometer-thick graphite film (∼100 nm, NGF) on Ni foil via a fast-thermal CVD approach (5 min growth). Moreover, we shed light on how localized thickness variations of the NGF relate to the Ni surface topography and grain characteristics. While on a macro-scale (mm2), the NGF film looks uniform-with a few hundred highly ordered graphene layers (d0002 = 0.335 nm), when studied at the micro- and nano-scales, few-layer graphene sections can be identified. These are present at a density of 0.1%-3% areas in 100 µ m2, can be as thin as two layers, and follow an epitaxial relation with the {111} fcc-Ni planes. Throughout the 50 cm2 NGF, the sharp graphite/substrate interfaces are either composed of a couple of NiCx layers or a graphene layer. Moreover, the NGF was successfully transferred on SiO2/Si substrate by a wet chemical etching method. The as-produced NGFs could complement or offer an alternative to the mm-thick films produced from natural graphite flakes or polymer sheets.

13.
Molecules ; 25(8)2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32340214

RESUMO

In this study, the influence of phenolic compounds on the sensory scores attributed to extra virgin olive oil (EVOO) by panel test was investigated. Two model olive oils (MOOs) with identical concentrations of volatile compounds, differing only in the amount of biophenols (297 vs. 511 mg kg-1), were analysed by two official panels and by SPME-GC/MS. Six other MOOs set up by the two previous models were also tested and analysed. They were formulated separately with the addition of three off-flavours ('rancid', 'winey-vinegary' and 'fusty-muddy'). While high levels of EVOO phenolic compounds did not produce any effect on the headspace concentration of volatile compounds, they did affect the scores of both positive and negative sensory attributes of EVOO, due to the well-known in-mouth interactions between EVOO phenols, saliva and volatile compounds. In particular, a decrease of about 39% in the positive fruity score was found in the presence of a higher concentration of phenols. Regarding EVOO off-flavours, the higher level of phenolic compounds decreased by about 23% the score of 'fusty-muddy' defect and increased the score of 'winey-vinegary' defect about 733%. No important effect of EVOO phenolics on the perceived intensity of the 'rancid' defect was found. These findings could be helpful in explaining some discrepancies of panel test responses observed during extra virgin olive oil shelf life.


Assuntos
Aromatizantes/análise , Azeite de Oliva/análise , Fenóis/análise , Paladar , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Percepção Gustatória , Compostos Orgânicos Voláteis
14.
J Sci Food Agric ; 100(9): 3755-3764, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32253752

RESUMO

BACKGROUND: The present study reports for the first time the physical, chemical and sensory characterization of a traditional fish sauce from Italy, called 'Colatura di Alici', which is considered to be the direct descendant of the ancient roman sauce 'Garum'. RESULTS: Among the volatile compounds, carboxylic acids, aldehydes, sulphuric compounds and pyrazines were identified. The most abundant compounds identified were 3-methyl-butanoic acid, nonanal and 3-methyl-butanal. The sample A had the highest amount of volatile fatty acids (>250 µg kg-1 ) and sample B had the highest concentration of aldehydes (>80 µg kg-1 ). These volatile compounds arise from the long fermentation activity and oxidation of fatty acids of the fish flesh and are responsible for the strong cheesy and fishy aroma. The protein content ranged from 90 to 130 g kg-1 , and the soluble solids ranged from 30 to 38 °Brix, as a result of the high amount of NaCl used during processing. The sensory analysis showed a great intensity for the cheesy, fishy and umami attributes, and a medium intensity for the roasted and meaty attributes. CONCLUSION: For the first time, the volatile compounds and sensory characteristics of this traditional fish sauce are reported. The samples differ in terms of sensory and aromatic profiles. These differences are probably linked to the poorly standardized methods used in the production process. Overall, the results of the present study could be used by local fish sauce producers to monitor the quality of the product and to improve the production process. © 2020 Society of Chemical Industry.


Assuntos
Produtos Pesqueiros/análise , Paladar , Compostos Orgânicos Voláteis/química , Animais , Ácidos Graxos Voláteis/química , Peixes , Aromatizantes/química , Humanos , Itália , Odorantes/análise
15.
Molecules ; 25(6)2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32183410

RESUMO

This paper aimed to assess the effects of feeding fresh forage on volatile organic compounds (VOCs) of buffalo milk and mozzarella cheese. Sixteen lactating buffaloes were equally allotted into two groups fed diets containing (experimental (Exp) group) or not (control (Ctl) group) 20 kg/d of fresh sorghum. Milk from the groups was separately collected and transformed in the traditional 'Mozzarella di Bufala Campana' Protected Denomination of Origin (PDO). Three batches of mozzarella were produced for each diet and they were analyzed, along with the two bulks of milk, for VOC composition, by using solid phase micro-extraction (SPME) coupled with gas-chromatography/mass spectrometry (GC/MS). The use of fresh forage increased the levels of long chain fatty acids along with the contents of aldehydes, and this could be responsible for an increase in green notes of milk. The use of the Ctl diet, containing a higher proportion of silage, increased the ketones, acids, and esters, which are compounds that could raise the cheese and fruity notes of milk. The mozzarella was less affected by the dietary treatment than milk. The use of fresh forage (sorghum) enhanced the green notes of milk and induced a few changes in the VOC profile of the typical PDO Mozzarella di Bufala Campana cheese, that were nonetheless detectable by sensory analysis. The low level found for butanoic acid, 2,3-pentanedione, and propyl acetate in mozzarella cheese obtained with fresh forage diet can lead to perceive less the olfactory notes of cheese, cream, and fruit.


Assuntos
Búfalos/metabolismo , Lactação/efeitos dos fármacos , Leite/efeitos dos fármacos , Compostos Orgânicos Voláteis/farmacologia , Animais , Queijo , Dieta/métodos , Ésteres/metabolismo , Ácidos Graxos/metabolismo , Feminino , Leite/metabolismo , Silagem
16.
Food Res Int ; 126: 108686, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31732045

RESUMO

The effect of the presence of virgin olive oil (VOO) phenolic compounds was studied during the in-vivo consumption of an olive oil-in-water (O/W) food emulsion, assessed by APCI-MS. VOO phenolic compounds were present at 593 mg kg-1. Four volatile compounds, i.e. ethyl acetate, hexanal, hexanol and linalool, were monitored based on their physicochemical characteristics and their aroma impact. Olive O/W emulsions were stabilized by whey protein isolate (WPI) and xanthan gum. Our results suggested that ethyl acetate and hexanal have a "salting out" effect in the presence of VOO phenolics at swallowing of emulsion. Among the volatiles investigated, hexanal showed the highest release. The persistence in the breath was higher for linalool only, potentially due to its higher hydrophobicity. This study could be beneficial in the formulation of new functional foods to enhance aroma release and persistence in the presence of natural phenolic compounds.


Assuntos
Espectrometria de Massas/métodos , Odorantes/análise , Azeite de Oliva/química , Fenóis/análise , Compostos Orgânicos Voláteis/análise , Emulsões/química
17.
Sci Rep ; 9(1): 13987, 2019 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-31562349

RESUMO

Highly porous particles with internal triply periodic minimal surfaces were investigated for sorption of proteins. The visualization of the complex ordered morphology requires complementary advanced methods of electron microscopy for 3D imaging, instead of a simple 2D projection: transmission electron microscopy (TEM) tomography, slice-and-view focused ion beam (FIB) and serial block face (SBF) scanning electron microscopy (SEM). The capability of each method of 3D image reconstruction was demonstrated and their potential of application to other synthetic polymeric systems was discussed. TEM has high resolution for details even smaller than 1 nm, but the imaged volume is relatively restricted (2.5 µm)3. The samples are pre-sliced in an ultramicrotome. FIB and SBF are coupled to a SEM. The sample sectioning is done in situ, respectively by an ion beam or an ultramicrotome, SBF, a method so far mostly applied only to biological systems, was particularly highly informative to reproduce the ordered morphology of block copolymer particles with 32-54 nm nanopores and sampling volume (20 µm)3.

18.
Molecules ; 24(8)2019 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-31022876

RESUMO

Seed inoculation of forage crops by arbuscular mycorrhizal fungi (AMF) generally results in higher profitability, but also modifies the chemical composition of silage in terms of increased biomass, protein, and dry matter. Raw milk aroma is affected by the type of feed. This work investigated the influence of ensiled forage obtained by seed inoculation with AMF on the volatile fractions and fatty acid composition of milk. Two experiments were carried out: in the first, buffaloes were fed maize silage, and in the second, cows were fed sorghum silage. The volatile fractions of milk were quantified by headspace solid-phase micro-extraction (HS-SPME), combined with gas chromatography-mass spectrometry (GC-MS), and fatty acids by gas chromatography (GC). The ensiled forage obtained with AMF increased saturated fatty acids (SFAs), and decreased monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) in both experiments. The volatile fraction in milk samples obtained from bovines fed mycorrhizal ensiled forage showed an increase of free fatty acids and ketones, responsible for cheesy and fruity odors. Aldehydes, responsible for green and grassy notes, increased only in the milk from buffaloes fed ensiled maize. Our results suggest that inoculation of maize and sorghum seed with AMF, combined with a low rate of fertilizers, leads to ensiled forage that could slightly affect the FA profile and odor quality of milk.


Assuntos
Ração Animal , Ácidos Graxos/química , Leite/química , Compostos Orgânicos Voláteis/química , Animais , Búfalos , Bovinos , Ácidos Graxos/isolamento & purificação , Feminino , Lactação , Micorrizas/metabolismo , Silagem/microbiologia , Compostos Orgânicos Voláteis/isolamento & purificação , Zea mays/metabolismo , Zea mays/microbiologia
19.
Food Res Int ; 116: 548-558, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30716979

RESUMO

In this study a Retronasal Aroma Simulator was employed to compare the release of volatiles from two different white wine matrices (TW: table, SW: sweet) with and without the addition of human or artificial saliva to simulate retronasal and orthonasal conditions, respectively. The headspace volatiles were isolated by Solid Phase Microextraction under dynamic conditions and identified and quantified by Gas-Chromatographic analyses. Compared to the orthonasal, the retronasal conditions modified the release of odorants from both wines and the observed trends cannot be ascribed only to dilution consequent to saliva addition. The relative amounts of volatiles belonging to different chemical classes were modified in the presence of saliva with possible sensory implications concerning some fruity (esters), oxidative (furans) and varietal (linalool, vitispirane) odorants. Regression analyses show that the impact of saliva depends on the volatile (concentration and hydrophobicity) and the non-volatile (residual sugars) composition of the wine. The highly significant linear models (TW: R2 = 0.988; SW: R2 = 0.993) indicate that the release of volatiles is logP octanol/water dependent in both the wines but the slopes change with matrix composition. This suggest that in the presence of human saliva the release of odorants with similar hydrophobicity vary as a linear function of their initial headspace concentration above the wine and is modulated by the composition of the wine matrix. Differences between artificial and human saliva confirmed that the retronasal release of wine odorants is affected by the whole salivary composition and suggest that salivary components different from mucin and α-amylase are involved in the retention of the most hydrophobic volatiles as well as in the metabolization of some aromas.


Assuntos
Odorantes/análise , Saliva/química , Olfato , Compostos Orgânicos Voláteis/análise , Vinho/análise , Adulto , Feminino , Ionização de Chama , Microbiologia de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Interações Hidrofóbicas e Hidrofílicas , Masculino , Microextração em Fase Sólida , Vinho/microbiologia , Adulto Jovem
20.
J Sci Food Agric ; 99(3): 1215-1224, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30066487

RESUMO

BACKGROUND: Extra virgin olive oil (EVOO) volatile composition is mainly used as a means of characterisation and authentication, especially for protected denomination of origin (PDO) products. This work investigated the volatile compounds from 25 EVOOs from four Spanish (Cornicabra, Manzanilla Castellana, Picual and Manzanilla Cacereña) and four Italian (Ortice, Ravece, Nocellara del Belice and Itrana) cultivars in terms of odour activity value (OAV). Forty-seven volatile compounds were analysed by solid phase microextraction gas chromatography/mass spectrometry (SPME-GC/MS). OAVs of volatile compounds with similar descriptors were grouped in order to establish eight odorant series: fruity, grass, apple, tomato, floral, woody-spicy, fatty and mushroom. RESULTS: No differences in sensory descriptors were observed among the EVOOs analysed by official VOO sensory analysis. The method of odorant series applied herein was demonstrated to successfully characterise EVOO odour as expected from a sensory panel but using only instrumental analysis of volatile compounds, and giving additional reliable quantitative information. The results can be presented as a 'barcode', providing a visual and effective graphical representation allowing an easy and rapid description of EVOO sensory attributes using instrumental data. CONCLUSION: The odorant series have the potential to better differentiate the aroma of food products, opening new possibilities allowing a schematic and effective visual representation to be used for EVOO quality control and consumer information, especially in new olive oil consuming countries. © 2018 Society of Chemical Industry.


Assuntos
Aromatizantes/química , Olea/química , Azeite de Oliva/química , Compostos Orgânicos Voláteis/química , Aromatizantes/isolamento & purificação , Frutas , Cromatografia Gasosa-Espectrometria de Massas , Itália , Odorantes/análise , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/isolamento & purificação
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