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1.
Water Sci Technol ; 80(3): 563-574, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31596267

RESUMO

This study was conducted to evaluate the influence of chloride ions (Cl-) on organic contaminants decolorization by the Fe0-activated persulfate process (PS/Fe0), as well as the generation of transformation products. Orange II (OII) was chosen as the target pollution. The results indicated that Cl- influenced the OII decolorization by PS/Fe0 system, resulting in the generation of chlorine-containing by-products. OII containing Cl- solution can be efficiently decolorized by PS/Fe0 process, and the decolorization efficiencies changed depending on Cl- concentration due to the reaction between Cl- and sulfate radicals (SO4-•). The operating cost for 94% color and 64% chemical oxygen demand (COD) removal of the OII dye was estimated at 0.73 USD/m3. The chlorine-containing by-products, such as chlorobenzene, 3,5-dichloro-benzene-1,2-diol, and 2,3-dichloro-2,3-dihydro-1,4-naphthoquinone, were generated during the reaction. The results further indicated that increasing both PS concentration and temperature enhanced OII decolorization and reduced the generation of chlorine-containing intermediates. The addition of ultrasound can further decrease the generation of chlorine-containing intermediates under high-temperature conditions. The proposed pathways of decolorization of OII containing Cl- also indicated that SO4-• dominated the OII degradation, while the presence of Cl- led to the generation of chlorine-containing intermediates.


Assuntos
Cloretos , Modelos Químicos , Sulfatos , Cor , Ferro/química , Oxirredução
2.
Rev Col Bras Cir ; 46(4): e2211, 2019 Sep 09.
Artigo em Português, Inglês | MEDLINE | ID: mdl-31508734

RESUMO

OBJECTIVE: to evaluate the applicability of the "Timing of Acute Care Surgery" (TACS) color classification system in a tertiary public hospital of a developing country. METHODS: we conducted a longitudinal, retrospective study in a single center, from March to August 2016 and the same period in 2017. We opted for the selection of four surgical specialties with high demand for emergencies, previously trained on the TACS system. For comparisons with the previous classifications, we considered emergencies as reds and oranges and urgencies, as yellow, with an ideal time interval for surgery of one hour and six hours, respectively. RESULTS: non-elective procedures accounted for 61% of the total number of surgeries. The red, orange and yellow classifications were predominant. There was a significant improvement in the time before surgery in the yellow color after the TACS system. Day and night periods influenced the results, with better ones during the night. CONCLUSION: this is the first study to use the TACS system in the daily routine of an operating room. The TACS system improved the time of attendance of surgeries classified as yellow.


Assuntos
Tratamento de Emergência/classificação , Triagem/métodos , Brasil , Cor , Emergências , Tratamento de Emergência/estatística & dados numéricos , Humanos , Estudos Longitudinais , Sistemas de Informação em Salas Cirúrgicas , Salas Cirúrgicas , Estudos Retrospectivos , Especialidades Cirúrgicas/classificação , Especialidades Cirúrgicas/estatística & dados numéricos , Procedimentos Cirúrgicos Operatórios/classificação , Procedimentos Cirúrgicos Operatórios/estatística & dados numéricos , Centros de Atenção Terciária , Fatores de Tempo
3.
J Agric Food Chem ; 67(38): 10624-10636, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31483633

RESUMO

The freshness and color quality of postharvest tea leaves can be markedly prolonged and retained by proper preservation measures. Here, we investigated the dynamic changes of chlorophyll and its derivatives in postharvest tea leaves under different low-temperature treatments using natural withering as a control. Chlorophyll decomposition was found closely related with chlorophyllide, pheophorbide, and pheophytin. Low-temperature withering could slow chlorophyll degradation in postharvest tea leaves via significant inhibition on the enzyme activity and gene expression of Mg-dechelatase, chlorophyllase, and pheophorbide a oxygenase. At the initial stage of withering, a significant increase was observed in the chlorophyll content, expression of chlorophyll-synthesis-related enzymes (such as glutamyl-tRNA synthetase, etc.), and chlorophyll synthase activity in newly picked tea leaves. Moreover, an obvious decrease was found in the content of l-glutamate as the foremost precursor substance of chlorophyll synthesis. Hence, our findings revealed that the chlorophyll synthesis reaction was induced by the light-dehydration-stress in the initial withering of tea leaves. This study provides a theoretical basis for exploring preservation technology in actual green tea production.


Assuntos
Camellia sinensis/genética , Camellia sinensis/metabolismo , Clorofila/metabolismo , Manipulação de Alimentos/métodos , Regulação da Expressão Gênica de Plantas , Camellia sinensis/química , Camellia sinensis/crescimento & desenvolvimento , Hidrolases de Éster Carboxílico/genética , Hidrolases de Éster Carboxílico/metabolismo , Clorofila/química , Cor , Enzimas/genética , Enzimas/metabolismo , Oxigenases/genética , Oxigenases/metabolismo , Folhas de Planta/química , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Temperatura Ambiente
4.
Braz Oral Res ; 33: e009, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31508728

RESUMO

This study investigates the color correspondence of resin cements and try-in pastes, and the color stability of bonded lithium disilicate ceramic disks. Resin composite disks were fabricated (n = 36) to serve as the background for lithium disilicate disks prepared in two thicknesses (0.5 and 1.0 mm, n = 18 each). Two brands were used for try-in and cement procedures: Variolink Veneer and AllCem Veneer. For baseline, water was applied between the ceramic disks and their respective backgrounds to achieve the control group. This set was subjected to color measurement using an intraoral measurement device (T0). The try-in was inserted between background and ceramic, and this set was subjected to color measurement (T1). After adhesive procedures, the ceramic disk was placed under cement, and color measurement was performed with uncured cement (T2) and 24 h after light-curing (T3). Each set was immersed in distilled water and thermal-cycled, with color measurement being performed after 10,000 (T4) and 20,000 (T5) cycles. Color differences were calculated by CIELab (rEab) and CIEDE2000 (rE00). Data were analyzed by two-way ANOVA for repeated measurements and Tukey's test (α=5%). There was color correspondence of try-in and resin cement for the Variolink system, regardless of the ceramic thickness (p > 0.05). For the AllCem system, the thickness significantly influenced the color measurement (p < 0.001). The Variolink system also demonstrated color stability after 20,000 thermal cycles with rEab < 3.46 and rE00 < 2.25. It was concluded that the color correspondence between a try-in and its respective cement may vary according to resin cement composition.


Assuntos
Cor , Porcelana Dentária/química , Cimentos de Resina/química , Cerâmica/química , Facetas Dentárias , Técnicas In Vitro , Teste de Materiais , Pomadas/química
5.
J Appl Oral Sci ; 27: e20180453, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31411261

RESUMO

OBJECTIVE: This study was designed for the chemical activation of a 35% hydrogen peroxide (H2O2) bleaching gel to increase its whitening effectiveness and reduce its toxicity. METHODOLOGY: First, the bleaching gel - associated or not with ferrous sulfate (FS), manganese chloride (MC), peroxidase (PR), or catalase (CT) - was applied (3x 15 min) to enamel/dentin discs adapted to artificial pulp chambers. Then, odontoblast-like MDPC-23 cells were exposed for 1 h to the extracts (culture medium + components released from the product), for the assessment of viability (MTT assay) and oxidative stress (H2DCFDA). Residual H2O2 and bleaching effectiveness (DE) were also evaluated. Data were analyzed with one-way ANOVA complemented with Tukey's test (n=8. p<0.05). RESULTS: All chemically activated groups minimized MDPC-23 oxidative stress generation; however, significantly higher cell viability was detected for MC, PR, and CT than for plain 35% H2O2 gel. Nevertheless, FS, MC, PR, and CT reduced the amount of residual H2O2 and increased bleaching effectiveness. CONCLUSION: Chemical activation of 35% H2O2 gel with MC, PR, and CT minimized residual H2O2 and pulp cell toxicity; but PR duplicated the whitening potential of the bleaching gel after a single 45-minute session.


Assuntos
Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/toxicidade , Clareadores Dentários/química , Clareadores Dentários/toxicidade , Clareamento Dental/métodos , Análise de Variância , Catalase/química , Sobrevivência Celular , Células Cultivadas , Cloretos/química , Cor , Polpa Dentária/química , Polpa Dentária/diagnóstico por imagem , Dentina/química , Dentina/efeitos dos fármacos , Compostos Ferrosos/química , Compostos de Manganês/química , Odontoblastos/efeitos dos fármacos , Peroxidase/química , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Fatores de Tempo
6.
World J Microbiol Biotechnol ; 35(9): 138, 2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31451937

RESUMO

Monascus azaphilone pigments, including red, orange, and yellow, are world-famous food colorants. However, the pigments produced by different Monascus species vary in yields and compositions. The underlying mechanism is unclear. In this study, four wild-type Monascus strains, namely M. anka M7, M. purpureus M9, M. ruber C100, and M. aurantiacus M15, were selected as research objects according to the diversification of their pigments fermented in the same mediums and conditions. Twenty-three 3 kbp segments (300 bp overlap with adjacent segments) of the pigment gene cluster were amplified, sequenced, and assembled into the DNA sequences of the clusters. The DNA sequences of pigment biosynthetic gene clusters of the four strains showed 99.94% similarity according to the results of multiple alignment. The expression levels of 17 pigment biosynthetic genes of four strains were determined by using real-time quantitative PCR. The transcriptional regulation contributed more than the DNA sequence variation in Monascus pigments metabolism. Our result gives insight into the study of Monascus pigment biosynthesis.


Assuntos
Monascus/genética , Monascus/metabolismo , Pigmentos Biológicos/biossíntese , Transcrição Genética , Sequência de Aminoácidos , Sequência de Bases , Cor , DNA Fúngico/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Variação Genética , Monascus/química , Monascus/classificação , Família Multigênica , Filogenia , Pigmentos Biológicos/química
7.
Am J Dent ; 32(4): 159-164, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31436934

RESUMO

PURPOSE: To compare the effect of thermal cycling and erosive challenge on color change, surface roughness, surface loss and biofilm deposition of three resin-based composites. METHODS: Three resin-based composites that reproduce the color of gingival tissues [two nanohybrid composites (A and B) and a giomer (C) ] were tested before and after distinct challenges [ thermal cycling (TC) and erosive challenge (EC) ] in regard to its color stability, surface roughness, surface loss and biofilm deposition. Surface roughness and surface loss specimens (n=10) were measured with an optical profilometer and, color stability (n=10) was measured with a spectrophotometer. Biofilm deposition (n=5) was measured after 3 and 24 hours by safranin staining. RESULTS: Two-way ANOVA test was performed to analyze color change, roughness and surface loss. A significant color change was detected for resin-based composites (P< 0.05) and its interaction with tested challenges (P< 0.05). The highest color variation was observed on the giomer after erosive challenge. Surface loss was not different between tested groups (P= 0.708). The roughness was significantly higher in specimens submitted to thermal cycling (P> 0.05). For biofilm quantification, after 3 and 24 hours, ANOVA (3-way) detected significance for the interaction of challenges and resin-based composites (P< 0.05 and P< 0.05, respectively). All resin-based composites presented color changes after challenges; higher roughness was observed after thermal cycling for all resin-based composites tested, without significant surface loss; and higher biofilm deposition was observed on the giomer samples when submitted to erosive challenge after 3 and 24 hours. CLINICAL SIGNIFICANCE: Pink esthetic is as important as dental esthetics and some restorative materials can mimic gingival tissue. However, the tested giomer must be indicated with caution, since it presented significant changes after thermal and acid challenges.


Assuntos
Resinas Compostas , Materiais Dentários , Cor , Estética Dentária , Teste de Materiais , Propriedades de Superfície
8.
Water Sci Technol ; 80(1): 134-143, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31461430

RESUMO

The aim of this article was to clarify which type of dye chromophores could be decolorized efficiently with the use of laccase enzyme. For this purpose, enzymatic degradation of different type of dye classes (4 reactive, 2 acid and 1 basic dye) having various chromophore groups was investigated by using commercial laccase from Cerrena unicolor. It was observed that the chromophore structure of dye is very important on enzymatic color removal efficiency. According to the experimental results, it was found that color removal efficiencies (20 mg/L initial dye) were 98.7% for RB220 (0.1 g/L enzyme after 6 h), 95.1% for RB19 (0.1 g/L enzyme after 48 h), 90.8% for AR42 (0.1 g/L enzyme after 48 h) while they were 60.9% for AR114 (0.25 g/L enzyme), 58.6% for RB21 (0.5 g/L enzyme), 39.7% for RR239 (0.25 g/L enzyme) even after seven days. As a result, it can be said that the highest decolorization rate was achieved for the reactive dye having formazan copper complex (RB220) chromophore. On the other hand, the enzymatic degradation of basic dye (BB9) was found to be rather difficult compared to the acid and reactive dyes used in this study and the maximum color removal was 42.8% after seven days.


Assuntos
Corantes/análise , Lacase/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Cor , Corantes/química , Cobre , Poluentes Químicos da Água/química
9.
Chem Commun (Camb) ; 55(71): 10571-10574, 2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31417999

RESUMO

A portable dual-mode sensing platform based on a self-standing TiO2 nanotube membrane is developed for simultaneously performing both qualitative analysis by the naked eye and quantitative analysis by ionic current. This dual-mode diagnosis strategy exhibits a high performance in telomerase detection in urine specimens from patients with bladder cancer.


Assuntos
Nanotubos/química , Telomerase/urina , Titânio/química , Neoplasias da Bexiga Urinária/diagnóstico , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Cor , Ouro/química , Humanos , Membranas Artificiais , Nanopartículas Metálicas/química , Prata/química , Neoplasias da Bexiga Urinária/urina
10.
Phys Chem Chem Phys ; 21(35): 18988-18998, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31464320

RESUMO

Computational approaches have to date failed to fully capture the large (about 0.4 eV) excitation energy tuning displayed by the nearly identical anionic chromophore in different green fluorescent protein (GFP) variants. Here, we present a thorough comparative study of a set of proteins in this sub-family, including the most red- (phiYFP) and blue-shifted (mTFP0.7) ones. We employ a classical polarisable embedding through induced dipoles and combine it with time-dependent density functional theory and multireference perturbation theory in order to capture both state-specific induction contributions and the coupling of the polarisation of the protein to the chromophore transition density. The obtained results show that only upon inclusion of both these two effects generated by the mutual polarisation between the chromophore and the protein can the full spectral tuning be replicated. We finally discuss how this mutual polarisation affects the correlation between excitation energies, dipole moment variation, and molecular electrostatic field.


Assuntos
Cor , Polarização de Fluorescência , Proteínas de Fluorescência Verde/química , Eletricidade Estática
12.
J Agric Food Chem ; 67(32): 8938-8949, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31361121

RESUMO

Polymeric pigments formed via ethyl linkages between grape tannins and anthocyanins are important to the development of stable red wine color. To determine the effect of tannin structure on the stability and color properties of ethyl-linked polymeric pigments, tannin fractions with average polymerization between 4 and 43 units were prepared from grape skins and seeds and combined with malvidin-3-glucoside (M3G) in model wine containing acetaldehyde. As tannin molecular mass increased, the reaction rate with M3G increased. Compared with skin tannins of comparable molecular mass, seed tannins reacted more rapidly with M3G but were prone to precipitation. This resulted in a loss of polymeric pigments formed from seed tannins, which was greater as tannin molecular mass increased. Aggregation occurred following the reaction of seed tannin with M3G, concomitant with precipitation. The aggregation-precipitation phenomenon was not observed for skin tannin-derived pigments, indicating a greater stability in solution than those formed from seed tannins.


Assuntos
Acetaldeído/química , Antocianinas/química , Pigmentos Biológicos/química , Extratos Vegetais/química , Sementes/química , Taninos/química , Vitis/química , Precipitação Química , Cor , Frutas/química , Cinética , Peso Molecular , Polimerização , Polímeros/química
13.
Bioresour Technol ; 291: 121801, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31326685

RESUMO

Achieving high biomass productivity is critical for establishing a successful large-scale algal facility. Microalgae cultures in raceway ponds are normally light limited. To achieve high biomass productivity, there is a need to develop a system to deliver light into the depth of microalgal cultures in raceway ponds. We investigated red and blue luminescent solar concentrators (LSCs) in outdoor raceway ponds to downgrade the sunlight, re-emit and, deliver it into the depth of Arthrospira platensis culture operated at 21 cm depth. When red LSCs were used, the biomass productivity (12.2 g m-2 d-1) and phycocyanin productivity (8.5 mg L-1 d-1) of A. platensis increased 26% and 44%, respectively. However, using blue LSCs resulted in no significant increase in A. platensis biomass productivity. Therefore, for generating same phycocyanin productivity using red LSCs, 44% less cultivation area would be required. This can lead to a significant reduction in the cost of phycocyanin production.


Assuntos
Biomassa , Ficocianina/biossíntese , Tanques/microbiologia , Spirulina/metabolismo , Cor , Luminescência , Microalgas/metabolismo , Luz Solar
14.
Bioresour Technol ; 291: 121846, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31362199

RESUMO

The aim of this study was to evaluatethe effects of different colored light emitting diodes (LEDs) on the growth, pigment yield, and photosynthetic performance of Arthrospira maxima, a commercially exploited species of cyanobacteria. The highest growth and chlorophyll a (Chl a) concentration were obtained under red LED and white fluorescent light, while the lowest growth and Chlaconcentration were observed under blue LED. However, blue LED produced the highest levels of phycobiliproteins (3.20 mg·g-1phycocyanin [PC]; 0.19 mg·g-1 allophycocyanin [APC]; 0.97 mg·g-1for phycoerythrin [PE], effective quantum yield (ΦPSII) and maximum relative electron transport rate (rETRmax) inA. maxima. The results of this study suggest that red and blue LEDs increase the biomass yield and pigment content of cyanobacteria, respectively, and the combined use of red and blue light may significantly improve algal biomass and biopigment yield.


Assuntos
Fotossíntese , Spirulina/metabolismo , Biomassa , Clorofila A/metabolismo , Cor , Iluminação/métodos , Pigmentos Biológicos/metabolismo
15.
BMC Plant Biol ; 19(1): 287, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31262258

RESUMO

BACKGROUND: The majority of apricot (Prunus armeniaca L.) cultivars display orange or yellow background skin, whereas some cultivars are particularly preferred by consumers because of their red blushed skin on the background. RESULTS: In this study, two blushed ('Jianali' and 'Hongyu') and two nonblushed ('Baixing' and 'Luntaixiaobaixing') cultivars were used to investigate the formation mechanism of blushed skin in apricots. High-performance liquid chromatography (HPLC) analysis showed that the blushed cultivars accumulated higher cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside and peonidin-3-O-rutinoside levels during fruit ripening than the nonblushed cultivars. Based on coexpression network analysis (WGCNA), a putative anthocyanin-related R2R3-MYB, PaMYB10, and seven structural genes were identified from transcriptome data. The phylogenetic analysis indicated that PaMYB10 clustered in the anthocyanin-related MYB clade. Sequence alignments revealed that PaMYB10 contained a bHLH-interaction motif ([DE]Lx2[RK]x3Lx6Lx3R) and an ANDV motif. Subcellular localization analysis showed that PaMYB10 was a nuclear protein. Real-time qRT-PCR analysis demonstrated that the transcript levels of PaMYB10 and seven genes responsible for anthocyanin synthesis were significantly higher in blushed than in nonblushed apricots, which was consistent with the accumulation of anthocyanin. In addition, bagging significantly inhibited the transcript levels of PaMYB10 and the structural genes in 'Jianali' and blocked the red coloration and anthocyanin accumulation. Transient PaMYB10 overexpression in 'Luntaixiaobaixing' fruits resulted in the red blushed skin at the maturation stage. CONCLUSIONS: Taken together, these data reveal that three anthocyanins are responsible for the blushed skin of apricots, identify PaMYB10 as a positive regulator of anthocyanin biosynthesis in apricots, and demonstrate that blush formation depends on light.


Assuntos
Antocianinas/biossíntese , Regulação da Expressão Gênica de Plantas , Pigmentos Biológicos/biossíntese , Proteínas de Plantas/genética , Prunus armeniaca/fisiologia , Fatores de Transcrição/genética , Sequência de Aminoácidos , Antocianinas/genética , Cromatografia Líquida de Alta Pressão , Cor , Frutas/genética , Frutas/fisiologia , Glucosídeos/biossíntese , Glucosídeos/genética , Filogenia , Pigmentos Biológicos/genética , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Prunus armeniaca/genética , Alinhamento de Sequência , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo
16.
Ying Yong Sheng Tai Xue Bao ; 30(6): 2109-2115, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257786

RESUMO

Light trap is commonly used in protecting Anguilla marmorata resource and improving the attraction of eel passage entrance. In this study, a self-made multifunctional round pool was used to explore the phototaxis of elvers (A. marmorata) under three conditions. 3 W underwater landscape lamp was used as the light source. The results showed that the percentages of juvenile A. marmorata occurrence in light zone and dark zone were (8.7±0.3)% and (3.6±1.7)%, (8.4±0.2)% and (5.0±1.4)%, (9.0±0.2)% and (1.9±1.3)% respectively under three conditions. Moreover, most glass eel distributed in the light zone, while elver (or elver develop) distributed in the dark zone. The primary regions of fish occurrence and its percentages were yellow zone [(29.4±4.9)%], red zone [(24.1±3.9)%)] and purple zone [(17.2±4.0)%] for condition one, yellow zone [(29.4±3.3)%], purple zone [(25.2±3.7)%] and red zone [(18.2±2.9)%] for condition two, and red zone [(33.3±2.3)%], purple zone [(25.6±3.8)%] and yellow zone [(20.7±5.7)%] for condition three. Correspondingly, the top three regions of fish first entering were red, yellow and purple, red, purple and yellow, and red, purple and yellow, respectively. The number of entering and exiting for fish in those three color zones was between blue-green zone and colorful zone. Visual fatigue would occur for elvers with continuous exposure to red light or yellow light. Our results suggested that the phototaxis of elvers is dependent on their developmental stages. Glass eels have phototaxis and seem to be more interesting in red, yellow, and purple light. Light guidance fish is available in the entrance of eel passage, which can help glass eels find the migration channels.


Assuntos
Anguilla , Fototaxia , Animais , Cor , Luz
17.
J Agric Food Chem ; 67(33): 9344-9353, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31361957

RESUMO

Anthocyanins determine the color and potential health-promoting properties of red fruit juices, but the juices contain remarkably less anthocyanins than the fruits, which is partly caused by the interactions of anthocyanins with the residues of cell wall polysaccharides like pectin. In this study, pectin was modified by ultrasound and enzyme treatments to residues of polysaccharides and oligosaccharides widely differing in their molecular weight. Modifications decreased viscosity and degrees of acetylation and methylation and released smooth and hairy region fragments. Native and modified pectin induced different effects on the concentrations of individual anthocyanins after short-term and long-term incubation caused by both hydrophobic and hydrophilic interactions. Results indicate that both pectin and anthocyanin structure influence these interactions. Linear polymers generated by ultrasound formed insoluble anthocyanin complexes, whereas oligosaccharides produced by enzymes formed soluble complexes with protective properties. The structure of the anthocyanin aglycone apparently influenced interactions more than the sugar moiety.


Assuntos
Antocianinas/química , Beta vulgaris/química , Pectinas/química , Acetilação , Cor , Frutas/química , Sucos de Frutas e Vegetais/análise , Interações Hidrofóbicas e Hidrofílicas , Metilação , Peso Molecular , Ultrassom , Viscosidade
18.
Phys Chem Chem Phys ; 21(30): 16848-16858, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31322152

RESUMO

A key utility of fluorophores lies in sensing applications: the detection of changes to emission caused by differences in their microenvironment. The rational design of fluorescent sensors remains a significant challenge because of the complexity of factors which control molecular deactivation pathways. Here, in an effort to define the structural criteria underlying the fluorescence turn-on response of Hoechst 33258 (H33258) upon binding to the DNA minor groove, we examine this sensor's intrinsic properties in minimalist microenvironments. We first characterised the intrinsic photophysics of gaseous mono- and di-protonated H33258 ions, then introduced intermolecular interactions by complexation with double-stranded (ds) DNA. Selected-ion laser-induced fluorescence (SILIF) and photodissociation of the gaseous monoprotomers indicate the presence of multiple populations with distinct fluorescence and dissociation properties. We assign one of these to a kinetically-trapped form which is protonated at the site favored in solution. The other form exhibits a more intense emission band which is shifted by more than 6000 cm-1 to the red of the first form. Quantum chemical calculations reveal that this second population is likely a newly-identified protomer, which is considerably more stable in the gas phase than conformations with the solution protonation site. Two routes that increase the fluorescence of H33258 in solution - formation of the diprotomer and complexation with dsDNA - do not produce an increase in fluorescence in the gas phase. However, two other outcomes parallel behaviour. First, the similarity of action spectra of the gaseous dsDNA-H33258 complex and the unbound diprotomer suggest that the dye may be diprotomeric when in complex with gaseous dsDNA. Second, the photodissociation power dependence measurements indicate the presence of at least two distinct populations of both H33258 in complex with dsDNA and in its unbound diprotomeric form. Overall, the results reported here reveal unexplored aspects of the potential energy landscape of H33258, including a new, stable, highly-fluorescent form that may be useful to consider in sensing applications. Moreover, the results reinforce how structure, deactivation pathways and other photophysical properties are intertwined for this DNA-binding dye, which may offer strategies for improved control of DNA-targeting drugs and sensors.


Assuntos
Bisbenzimidazol/química , DNA/química , Cor , Fluorescência
19.
Food Chem ; 299: 125043, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31299516

RESUMO

Jaggery is a non-centrifugal sweetener produced by thermo-chemical treatments of sugarcane juice. The traditional practices involved in making jaggery are usually tailored using chemicals to meet consumer requirements. Sodium hydrosulphite (hydros) is a commonly employed chemical in the jaggery industry to improve its colour. This article presents a comparative study of jaggery made with and without hydros treatments. The differences in properties, such as sorption behaviour, colour, polyphenols, flavonoids, minerals, and sulphur dioxide content, were measured. Hydros-treated jaggery was found to be brighter in colour with a lower browning index by 5-10. SO2 content of hydros-treated jaggery was >70 ppm, while minerals, polyphenols, and flavonoids were less abundant compared to control jaggery, thereby compromising overall quality. Based on the experiments carried out, the optimum treatment of hydros can be employed to satisfy consumer demand while producing an acceptable quality of jaggery that conforms to norms.


Assuntos
Ditionita/química , Qualidade dos Alimentos , Extratos Vegetais/química , Edulcorantes/química , Cor , Temperatura Ambiente
20.
Food Chem ; 299: 125112, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31299521

RESUMO

The objective of this work was to assess the impact of high-pressure processing (HPP) on the carotenoid profile, colour as well as the microbial and enzymatic stability of cloudy carrot juice. The predominant carotenoids in the fresh juices were by far the provitamin A carotenoids ß-carotene and α-carotene. Others were ζ-carotene, phytofluene, phytoene and lutein. HPP at 300 MPa in three cycles caused the highest carotenoids degradation (41%) whereas the lowest degradation (26%) was achieved at 600 MPa. The highest inactivation of POD (31%) and PPO (57%) was achieved with 600 MPa and 300 MPa applied in three cycles, respectively what indicates that POD is more responsible for carotenoids degradation. The colour differences (ΔE*ab) between fresh juice and HPP-treated juices ranged from 3.02 to 4.15 CIELAB units. As far as the impact on microorganism was concerned, there was a clear trend between the applied pressure and the microbial reduction achieved.


Assuntos
Carotenoides/química , Daucus carota/química , Indústria de Processamento de Alimentos/métodos , Sucos de Frutas e Vegetais , Carotenoides/análise , Catecol Oxidase/química , Cor , Estabilidade Enzimática , Armazenamento de Alimentos , Sucos de Frutas e Vegetais/microbiologia , Pressão
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