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1.
J Agric Food Chem ; 67(37): 10296-10305, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31464437

RESUMO

Grass pea is an orphan legume that is grown in many places in the world. It is a high-protein, drought-tolerant legume that is capable of surviving extreme environmental challenges and can be a sole food source during famine. However, grass pea produces the neurotoxin ß-N-oxalyl-L-α,ß-diaminopropionic acid (ß-ODAP), which can cause a neurological disease. This crop is promising as a food source for both animals and humans if ß-ODAP levels and other antinutritional factors such as protease inhibitors are lowered or removed. To understand more about these proteins, a proteomic analysis of grass pea was conducted using three different extraction methods to determine which was more efficient at isolating antinutritional factors. Seed proteins extracted with Tris-buffered saline (TBS), 30% ethanol, and 50% isopropanol were identified by mass spectrometry, resulting in the documentation of the most abundant proteins for each extraction method. Mass spectrometry spectral data and BLAST2GO analysis led to the identification of 1376 proteins from all extraction methods. The molecular function of the extracted proteins revealed distinctly different protein functional profiles. The majority of the TBS-extracted proteins were annotated with nutrient reservoir activity, while the isopropanol extraction yielded the highest percentage of endopeptidase proteinase inhibitors. Our results demonstrate that the 50% isopropanol extraction method was the most efficient at isolating antinutritional factors including protease inhibitors.


Assuntos
Fracionamento Químico/métodos , Fabaceae/química , Extratos Vegetais/isolamento & purificação , Inibidores de Proteases/isolamento & purificação , Sementes/química , Endopeptidases/química , Fabaceae/genética , Fabaceae/metabolismo , Espectrometria de Massas , Extratos Vegetais/química , Extratos Vegetais/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Inibidores de Proteases/química , Inibidores de Proteases/metabolismo , Proteômica , Sementes/genética , Sementes/metabolismo
2.
J Agric Food Chem ; 67(35): 9840-9850, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31424924

RESUMO

In the present study, methanolysis of poplar biomass was conducted for the selective transformation of hemicellulose and lignin, which leads to methyl glycosides (mainly C5 glycosides) and lignin fragments in the liquefied products that can be separated according to their difference in hydrophilicity. The distribution of methyl glycosides and delignification was dependent on the presence of acid catalysts and reaction temperatures. The obtained lignin fraction was separated into solid lignin fragments and liquid lignin oil according to their molecular weight distribution. Subsequently, directional conversion of methyl C5 glycosides into methyl levulinate was performed with dimethoxymethane/methanol as the cosolvent. A yield of 12-30% of methyl levulinate yield (based on the methyl glycoside) was achieved under these conditions. The remaining cellulose-rich substrate showed enhanced susceptibility to enzymatic hydrolysis, resulting in a yield of glucose of above 70%. Overall, the described strategy shows practical implications for the effective valorization of biomass.


Assuntos
Fracionamento Químico/métodos , Glucose/isolamento & purificação , Ácidos Levulínicos/isolamento & purificação , Metanol/química , Fenóis/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Populus/química , Madeira/química , Catálise , Celulose/química , Celulose/isolamento & purificação , Glucose/química , Ácidos Levulínicos/química , Lignina/química , Lignina/isolamento & purificação , Fenóis/química , Extratos Vegetais/química
3.
J Sci Food Agric ; 99(14): 6546-6551, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31328269

RESUMO

BACKGROUND: Proteins recovery using hydrochloric acid (HCl) in acid-aided solubilization could cause greater loss in its functionality over alkali-aided solubilization. Moreover, using HCl in edible foods is also a health concern. Replacing HCl with organic acids for acid-aided solubilization could address these problems. The aim was to study the effect of organic acid (glacial acetic acid) as a replacement for HCl during pH shift processing on the characteristics and functionality of rohu (Labeo rohita) protein isolates. Rohu proteins were obtained by solubilizing at pH 3.0 and pH 11.0 using glacial acetic acid and sodium hydroxide (10 mol L-1 ). RESULTS: Results showed that solubilization at pH 11.0 gave higher protein yields (766.8 ± 2.4 g kg-1 ) compared to solubilization at pH 3.0 (735.7 ± 7.1 g kg-1 ) (P < 0.05). Isolates from acid-aided solubilization had higher whiteness and total pigment content over isolates obtained by alkali-aided solubilization. Rohu isolates recovered by alkaline solubilization showed higher water and oil holding capacity, gel strength, folding scores, foaming and emulsion capacity than acid processed isolates (P < 0.05). Solubilization of rohu proteins using glacial acetic acid produced isolates with low breaking force (149.0 g), low storage modulus (G') values and low folding test score (1.0) over the alkaline isolates (P < 0.05). CONCLUSION: Results indicated that, recovering rohu proteins using organic acid (glacial acetic acid) could produce isolates with poor functional properties, while using the organic acid to precipitate the proteins solubilized by alkali-aided processing could produce proteins with better yields and functionality. © 2019 Society of Chemical Industry.


Assuntos
Fracionamento Químico/métodos , Proteínas de Peixes/isolamento & purificação , Manipulação de Alimentos/métodos , Ácido Acético/química , Animais , Cyprinidae , Proteínas de Peixes/química , Concentração de Íons de Hidrogênio , Solubilidade
4.
Food Chem ; 300: 125205, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31330372

RESUMO

For efficient extraction of amplifiable DNA from edible vegetable oils, we developed a novel DNA extraction approach based on the non-silica-based dipolar nanocomposites. The nanoparticle comprises a hydrophilic polymethyl methacrylate core with abundant capillaries, hydrophilic vesicles decorated with molecules having DNA affinity and a coating hydrophobic polystyrene layer. The nanoparticles are soluble in oil, adsorb the DNA from the aqueous phase and gave a high DNA recovery ratio. All DNA extracts from fully refined vegetable oil soybean, peanut, rapeseed, and cottonseed oils, including their blends, were sufficiently pure to be amplified by real-time PCR targeting the chloroplast ribulose-1,5-bisphosphate gene (rbcL), therefore, the species of origin and their ratios in mixed vegetable oils blended from two or three oil-species could be determined. These results indicate that the novel DNA isolation and real-time PCR kit is a simple, sensitive and efficient tool for the species identification and traceability in refined vegetable oils.


Assuntos
DNA de Plantas/isolamento & purificação , Nanopartículas/química , Óleos Vegetais/química , Reação em Cadeia da Polimerase em Tempo Real/métodos , Verduras/genética , Fracionamento Químico/métodos , Cloroplastos/genética , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Polimetil Metacrilato/química , Ribulosefosfatos/genética , Dióxido de Silício
5.
Soft Matter ; 15(30): 6160-6170, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31317157

RESUMO

We investigate by time-resolved synchrotron ultra-small X-ray scattering the dynamics of liquid-liquid phase-separation (LLPS) of gluten protein suspensions following a temperature quench. Samples at a fixed concentration (237 mg ml-1) but with different protein compositions are investigated. In our experimental conditions, we show that fluid viscoelastic samples depleted in polymeric glutenin phase-separate following a spinodal decomposition process. We quantitatively probe the late stage coarsening that results from a competition between thermodynamics that speeds up the coarsening rate as the quench depth increases and transport that slows down the rate. For even deeper quenches, the even higher viscoelasticity of the continuous phase leads to a "quasi" arrested phase separation. Anomalous phase-separation dynamics is by contrast measured for a gel sample rich in glutenin, due to elastic constraints. This work illustrates the role of viscoelasticity in the dynamics of LLPS in protein dispersions.


Assuntos
Fracionamento Químico/métodos , Glutens/isolamento & purificação , Viscosidade , Glutens/química , Espalhamento de Radiação , Síncrotrons , Temperatura Ambiente
6.
Food Chem ; 299: 125144, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31323440

RESUMO

Magnetic nanoparticles were synthesised to extract Sudan dyes from chilli powders. The adsorbents used were magnetic ferroferric oxide nanoparticles coated with polystyrene. The extraction procedures for Sudan dyes comprised liquid-solid extraction and magnetic solid phase extraction. The conditions were optimised to achieve efficient magnetic solid phase extraction, including extraction and desorption time, type and volume of the desorption solvent, and the mass of the adsorbents. Repeatability tests showed satisfactory recovery rates of 80.2-115.8%, with a relative standard deviation <3.8%. The results suggested that the proposed extraction method was effective and efficient to extract Sudan dyes from chilli powders. The extraction process was simpler compared with traditional approaches because the adsorbents can be rapidly removed from the sample matrix using a permanent magnet. The use of recyclable adsorbents decreased the cost greatly. Chilli powder samples collected from local markets in Singapore were tested using the proposed method under optimum conditions.


Assuntos
Capsicum/química , Corantes/análise , Contaminação de Alimentos/análise , Nanopartículas de Magnetita/química , Compostos Azo/análise , Fracionamento Químico/métodos , Cromatografia Líquida de Alta Pressão , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Pós/química , Reprodutibilidade dos Testes , Singapura , Extração em Fase Sólida/instrumentação , Extração em Fase Sólida/métodos
7.
Food Chem ; 300: 125185, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31326673

RESUMO

Bioactive compounds should be extracted using alternative solvents and enabling technologies, in accordance with green extraction principles. The aim of this study is to develop an eco-friendly extraction method for grape-pomace anthocyanins on a larger scale. From a preliminary screening of 8 different natural deep eutectic solvents (NADES), a combination of choline chloride:citric acid was selected because of its price, physicochemical properties, and anthocyanin recovery and stability. The effects of multimode-microwave (MW), and low-frequency-ultrasound (US) irradiation (used alone or simultaneously), as well as that of process parameters on extraction efficiency have been investigated in order to maximise anthocyanin extraction yield. The best conditions were found to be: simultaneous ultrasound/microwave-assisted extraction (UMAE) (MW power at 300 W, US power 50 W), for 10 min with 30% (v/v) of water. This gave 1.77 mg gdw-1 of anthocyanins. Anthocyanins were efficiently recovered from NADES, which were recycled. The optimised procedure was scaled up to a half-litre batch.


Assuntos
Antocianinas/isolamento & purificação , Fracionamento Químico/métodos , Solventes/química , Vitis/química , Micro-Ondas , Extratos Vegetais/química , Ultrassom
8.
Food Chem ; 300: 125188, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31336274

RESUMO

An effective, simple and sensitive analytical method has been developed employing liquid chromatography coupled with tandem mass spectrometry and validated for estimation of five organophosphate pesticides at trace levels in six fruits and twelve vegetables. Plackett-Burman design and central composite design was used to screen and optimize the significant factors in modified QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method. The method evaluation was done by matrix-matched calibration with linearity ranging from 5 to 500 µg/L with a correlation coefficient more than 0.990. The detection and quantification limit ranged from 0.1 to 1.0 µg/kg and 0.5 to 5 µg/kg, respectively. The mean recoveries were in the range of 76.89-110.30 % with the relative standard deviation less than 13.26% for all pesticides. Further, the method developed was applied to analyze real samples cultivated in the hill areas of Nilgiris, South India.


Assuntos
Fracionamento Químico/métodos , Contaminação de Alimentos/análise , Organofosfatos/análise , Praguicidas/análise , Calibragem , Cromatografia Líquida/métodos , Análise de Alimentos/métodos , Frutas/química , Índia , Análise Multivariada , Organofosfatos/isolamento & purificação , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/isolamento & purificação , Praguicidas/isolamento & purificação , Sensibilidade e Especificidade , Espectrometria de Massas em Tandem/métodos , Verduras/química
9.
Food Chem ; 300: 125200, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325748

RESUMO

Ethyl carbamate (EC) and N-nitrosoamines (NAs) are toxic contaminants which can be typically formed in fermented alcoholic beverages. In the present work, a novel approach for simultaneous analysis of EC and NAs in beer and yellow rice wine based on ice-bath assisted sodiumhydroxide purification and GC-MS/MS was firstly established. Samples were extracted with acetonitrile-ethyl acetate after addition of internal standards. The extraction solution system was purified by sodiumhydroxide solid under ice-bath. After concentration, target analytes were separated on a HP-INNOWAX quartz capillary column and determined under dynamic multiple reactions monitoring mode of MS/MS. The limits of detection and quantification (LOD and LOQ), matrix effect, recovery and precision of the method were evaluated. Results were linear in the concentration range 2-200 µg/L for all analytes of interest, with regression coefficients higher than 0.999. LODs and LOQs were in the ranges of 0.1-0.5 µg/kg and 0.5-1.5 µg/kg, respectively. The mean recoveries at three spiked levels were between 81.5% and 121.0%. The intra- and inter-day precisions were in the ranges of 2.2-9.4% and 1.6-7.9%, respectively. The validated method was successfully applied to determine thirteen targets in commercial beer and yellow rice wine. EC was detected in all beers and yellow rice wines with the concentrations ranging from 1.18 to 22.90 µg/L. Results indicated wide EC contamination and confirmed its urgency for monitoring EC in fermented alcoholic beverages.


Assuntos
Cerveja/análise , Contaminação de Alimentos/análise , Nitrosaminas/análise , Uretana/análise , Vinho/análise , Acetonitrilos/química , Fracionamento Químico/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Gelo , Limite de Detecção , Oryza , Reprodutibilidade dos Testes , Hidróxido de Sódio/química , Espectrometria de Massas em Tandem/métodos
10.
Food Chem ; 298: 124987, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260962

RESUMO

In this study, subcritical water extraction (SWE), SWE in aqueous citric acid (pH 5.0) (SWEC), and ultrasound-assisted SWEC (USWEC) were used to extract soluble dietary fiber (SDF) from wheat bran. Results showed that SWE-based methods significantly influenced the physicochemical, functional, and biological properties of the SDF. The fraction SDF-III attained via USWEC had higher SDF yield (46.30%) and carbohydrate content (82.91%), and lower weight-average molecular weight (65.2 kDa) and particle size (1.17 µm), and looser and more porous surface structure, compared with the SDF-I and SDF-II obtained by SWE and SWEC, respectively. USWEC increased the thermal stability and homogeneity of SDF-III but decreased its apparent viscosity and dynamic viscoelasticity. Moreover, the SDF-III exhibited more significant antioxidant and α-amylase inhibitory activities in vitro than SDF-I and SDF-II. Therefore, the USWEC technique had a greater potential for the highly-efficient production of SDF from wheat bran.


Assuntos
Fracionamento Químico/métodos , Fibras na Dieta , Antioxidantes/química , Antioxidantes/farmacologia , Ácido Cítrico/química , Fibras na Dieta/farmacologia , Difusão Dinâmica da Luz , Inibidores Enzimáticos/farmacologia , Concentração de Íons de Hidrogênio , Peso Molecular , Monossacarídeos/análise , Tamanho da Partícula , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Viscosidade , Água/química , alfa-Amilases/antagonistas & inibidores
11.
Food Chem ; 298: 125009, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260970

RESUMO

The objective of this study was to develop an accurate and fast method to determine malondialdehyde (MDA) levels in raw and processed meat. This method is based on extraction with trichloroacetic acid (TCA), reaction with 2-thiobarbituric acid (TBA) and quantification with ultraperformance liquid chromatography with a fluorescence detector (UPLC-FLD) with ʎexcitation = 530 nm and ʎemission = 550 nm and with a diode array detector (UPLC-DAD) with ʎabsorbance = 532 nm. The method tested was compared with the TBARS spectrophotometric method with ʎabsorbance = 532 nm. The concentration of MDA was similar for most of the matrices in both UPLC methods, except for cooked ham and frankfurter sausage. The TBARS spectrophotometric method overestimated the MDA concentration in all the matrices. Therefore, the use of both chromatographic methods, especially UPLC-FLD, to determine MDA would be more advisable than the classic TBARS method to avoid overestimation in meat and processed meat products.


Assuntos
Cromatografia Líquida/métodos , Análise de Alimentos/métodos , Malondialdeído/análise , Produtos da Carne/análise , Animais , Fracionamento Químico/métodos , Cromatografia Líquida/instrumentação , Culinária , Fluorescência , Malondialdeído/isolamento & purificação , Carne/análise , Espectrofotometria/métodos , Suínos , Tiobarbitúricos/química , Substâncias Reativas com Ácido Tiobarbitúrico/análise , Ácido Tricloroacético/química
12.
Ying Yong Sheng Tai Xue Bao ; 30(6): 1840-1846, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257754

RESUMO

We used two types of soil with different physicochemical properties (loam and sand), oven-dried them, and then added the known isotopic composition mineral water that was reference water to compose the soil-water mixture with different soil water contents (loam: 0.15, 0.20, 0.30 g·g-1; sand: 0.10 g·g-1). After that, we set up different equilibrium time (loam: 3, 6, 12, 24, 48, 72, 96 h; sand: 96 h) to ensure that the dry soil particles were well mixed with the added water. The soil water was extracted by mechanical centrifugation and cryogenic vacuum extraction after equilibrium, and their isotope composition was analyzed. Results showed that the isotopic values of soil water extracted by mechanical centrifugation method had no significant difference in same water content with different equilibration times, but were more enriched compared with the reference water isotopic value. The maximum enrichment for hydrogen and oxygen isotope was 7.38‰ and 1.24‰, respectively. In contrast, cryogenic vacuum extraction method resulted in more depleted soil water isotopes than reference water, with the maximum depletion for hydrogen and oxygen isotope being 6.27‰ and 1.03‰, respectively. Moreover, the degree of depletion increased with the increases of equilibrium time (less than 24 h) at low water content, and became stable after 24 h. With the increases of soil water content, the isotopic composition of the extracted soil water was less affected by the two extraction methods. The water isotope value of loam that had high clay content, was more sensitive to the extraction method than the sandy soil that had low clay content. The difference of isotopic composition caused by extraction methods did not affect the plant water source segmentation.


Assuntos
Fracionamento Químico/métodos , Plantas/química , Solo/química , Água , Deutério , Isótopos de Oxigênio/análise
13.
Food Chem ; 297: 124970, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253303

RESUMO

Choline chloride-based deep eutectic solvents (DESs) were used as green alternatives to conventional organic solvents for extracting valuable flavonoids from citrus peel waste. The effects of viscosity, pH, and polarity of DESs on the extraction efficiency were investigated. Results revealed linear dependence of extraction yield of citrus flavonoids on the polarity of the hydrogen bond donor (HBD). To simultaneously and effectively extract polymethoxylated flavonoids (PMFs) and glycosides of flavonoids (GoFs) with different polarities, five ternary DESs were designed and prepared by combining the effective HBD components. Among the tailor-made DESs studied, choline chloride-levulinic acid-N-methyl urea showed the highest extraction yield of total flavonoids. Under optimized extraction conditions, 18.75 mg/g PMFs and 47.07 mg/g GoFs were extracted from citrus peel with recoveries of 95.87% and 86.32%, respectively. This study presents a useful strategy based on tailor-made DESs to selectively extracted value-added flavonoids from waste peels in the citrus-processing industry.


Assuntos
Fracionamento Químico/métodos , Citrus/química , Flavonoides/isolamento & purificação , Solventes/química , Colina/química , Flavonoides/química , Glicosídeos/química , Glicosídeos/isolamento & purificação , Ligações de Hidrogênio , Concentração de Íons de Hidrogênio , Temperatura Ambiente , Viscosidade , Resíduos
14.
Food Chem ; 297: 124961, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253315

RESUMO

In this work, three versions of the QuEChERS method (original, AOAC 2007.01 and CEN 15662) were evaluated for the extraction of 38 multiclass pesticides from a mixture of five dried fruits: (strawberry, blackberry, passion fruit, pineapple and grapes) prior to their gas chromatography tandem mass spectrometry analysis. Among them, the AOAC 2007.01 method provided the best results in terms of lower amount of matrix co-extractives, matrix effect, extraction efficiency and precision. Its application to the analysis of the same pesticides in the individual dried fruits provided good recovery (between 70 and 120%) and relative standard deviation values (<20%) for most pesticides at three spiked levels. Matrix effect assessment revealed the necessity of taking into account such effect. Matrix-matched calibration data were also satisfactory for all analytes and matrices being the R2 ≥ 0.9900 and the lowest calibration level 5 µg/kg, which is lower than the agreed limit set at 10 µg/kg for monitoring purposes in food applications. Three samples of each type were also analysed, finding residues of metalaxyl, chlorpyrifos and iprodione in some of them.


Assuntos
Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Praguicidas/análise , Calibragem , Fracionamento Químico/métodos , Praguicidas/isolamento & purificação , Espectrometria de Massas em Tandem/métodos
15.
J Chromatogr A ; 1603: 278-287, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31208793

RESUMO

Revealing fractionations of chlorine and bromine isotope in electron ionization mass spectrometry (EI-MS) is crucial for accurate compound-specific isotope analysis of chlorine/bromine (CSIA-Cl/Br) for halogenated organic compounds (HOCs) using gas chromatography EI-MS (GC-EI-MS). This study investigated chlorine/bromine isotope fractionation of 12 organochlorines and 5 organobromines in EI-MS using gas chromatography-high resolution mass spectrometry. The observed isotope fractionations were evaluated with relative variation of chlorine/bromine isotope ratios (Δ37Cl or Δ81Br) between precursor ions and their product ions. All the 17 HOCs exhibited significant isotope fractionations with varied modes and magnitudes depending on compound and EI energy. The magnitudes of the observed isotope fractionations were extremely large in contrast to those in in-solution dehalogenation reactions, showing the Δ37Cl and Δ81Br values within the ranges of -149.2 to 292.0‰ and -362.2 to 546.2‰, respectively. Inter-ion and intra-ion isotope fractionations counteractively influenced the measured chlorine/bromine isotope ratios of individual dehalogenation product ions, whereas only the former could affect (enhance) the measured isotope ratios of molecular ions. The magnitudes of inter-ion isotope fractionation were generally lower than those of intra-ion isotope fractionation for most HOCs (11/17). Stable EI energy and isotope-ratio calculation using complete chlorine/bromine isotopologues of individual molecular ions help to obtain CSIA-Cl/Br data with high precision and accuracy. The results of this study could facilitate exploration of chlorine and bromine isotope fractionations of HOCs during dehalogenation in such conditions as photoinduced dehalogenation, and further elucidate relevant dehalogenation pathways in light of reaction mechanisms revealed by CSIA data.


Assuntos
Bromo/química , Fracionamento Químico/métodos , Cloro/química , Elétrons , Cromatografia Gasosa-Espectrometria de Massas/métodos , Hidrocarbonetos Halogenados/química , Íons , Isótopos/análise
16.
Carbohydr Polym ; 219: 29-38, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31151527

RESUMO

Multi-objective sequential fractionation of mango (Mangifera indica L.) peels for pectin and anthocyanins in a biorefinery, was investigated with the aims of enhancing pectin purity, bioactivity and increasing recovered products. Anthocyanins were extracted from mango peels based on a Box-Behnken experimental design (ethanol concentration (50-80%), acetic acid concentration (0.1-2%), time (60-150 min) and temperature (25 °C)). The remaining residue was subsequently fractionated to recover pectin. The optimum anthocyanin conditions (67.45% ethanol, 0.24% acetic acid and 60 min) resulted in pectin with a 5.5% higher antioxidant activity, it was 23% richer in polygalacturonic acid (PGA) and had a yield of 31% w/w higher than conventionally extracted pectin. An anthocyanin extract with anthocyanin contents, polyphenol contents, and antioxidant activity of 22.33 mg/100 g, 132.62 mg/g, and 1.36 µg gallic acid equivalent, respectively, was obtained. Therefore, the sequential extraction of anthocyanins and pectin improves pectin functional properties and increases the mango peel value potential.


Assuntos
Antocianinas , Fracionamento Químico/métodos , Frutas/química , Mangifera/química , Pectinas , Antocianinas/química , Antocianinas/isolamento & purificação , Pectinas/química , Pectinas/isolamento & purificação , Projetos de Pesquisa
17.
Food Chem ; 295: 441-448, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174780

RESUMO

Aerial surfaces of plants are covered by a waxy cuticle protecting plants from excessive water loss and UV light. In the present study, composition and morphology of cuticular waxes of northern wild berry species bilberry (Vaccinium myrtillus L.), lingonberry (V. vitis-idaea L.), bog bilberry (V. uliginosum L.) and crowberry (Empetrum nigrum L.) were investigated. Scanning electron microscopy (SEM) revealed differences in epicuticular wax morphology, and gas chromatography-mass spectrometry (GC-MS) analysis confirmed variation in chemical composition of cuticular waxes between the berry species. The dominant compounds in bilberry and lingonberry cuticular waxes were triterpenoids, while fatty acids and alkanes were the dominant ones in bog bilberry and crowberry, respectively. Wax extracted by supercritical fluid extraction (SFE) from industrial press cakes of bilberry and lingonberry contained linoleic acid and γ-linolenic acid as the dominant compounds. Furthermore, in vitro sun protection factor (SPF) of berry waxes depicted good UV-B absorbing capacities.


Assuntos
Mirtilos Azuis (Planta)/química , Vaccinium myrtillus/química , Vaccinium vitis-Idaea/química , Ceras/análise , Antocianinas , Fracionamento Químico/métodos , Ácidos Graxos/análise , Finlândia , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas , Fator de Proteção Solar , Raios Ultravioleta , Ceras/química , Ceras/isolamento & purificação
18.
Food Chem ; 297: 124924, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253284

RESUMO

Yeast nitrogen metabolism produces metabolites, whose origin in wines has scarcely been studied, with an important biological and organoleptic role. The present work focuses on comparing three intracellular extraction methods in order to elucidate efficiency of extraction while measuring the effect of temperature upon the integrity of the compounds related to the metabolism of tryptophan and tyrosine by yeast. Two UHPLC/HRMS methods to measure 16 metabolites were developed and validated. The validation provided optimum values of LOD (7.4·10-6 to 0.1 µg L-1), of LOQ (2·10-5 to 0.02 µg L-1) of precision (11-0.5% RSD) and repeatability (12-0.5% RSD). The removal of interfering molecules enabled matrix effects to be kept at low levels. The results pointed out that the low-temperature methods were more effective, providing better precision for 16 metabolites. The high-temperature extraction method may yield false enhanced compounds concentrations since they originate in cell wall macromolecules degradation.


Assuntos
Fracionamento Químico/métodos , Saccharomyces cerevisiae/metabolismo , Triptofano/análise , Tirosina/análise , Cromatografia Líquida de Alta Pressão , Temperatura Baixa , Congelamento , Glicerol/química , Espectrometria de Massas , Nitrogênio/metabolismo , Triptofano/metabolismo , Tirosina/metabolismo , Vinho/análise
19.
Vet Parasitol ; 270: 13-19, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31213236

RESUMO

Small ruminants browsing in tropical forests readily consume the foliage of Senegalia gaumeri. A S. gaumeri methanol:water extract was recently shown to have ovicidal activity against Haemonchus contortus eggs in vitro. In the present study, the fraction of a S. gaumeri methanol:water extract with ovicidal activity against H. contortus eggs and the metabolites potentially involved in this activity were identified. Bio-guided fractionation of the S. gaumeri methanol:water extract identified high ovicidal activity (80.29%, EC50 = 58.9 µg/mL) in the non-polar sub-fraction P1. Gas chromatography-mass spectrometry (GC-MS) identified several fatty acids: pentacosane (18.05%), heneicosane (18.05%), triacontane (30.94%), octacosane (18.05%), and hexanedioic acid bis-(2-ethylhexyl) ester (32.72%). Purification of the polar components of sub-fraction P1 led to the identification of p-coumaric acid as a major constituent. In egg hatch tests, 400 µg/mL p-coumaric acid resulted in an ovicidal effect of 8.7%, a larvae failing eclosion effect of 2.9%, and of the emerged larvae (88.4%), many were damaged. In conclusion, the low AH activity of p-coumaric acid against H. contortus eggs indicates that it is not solely responsible for the ovicidal activity of sub-fraction P1 but might act in synergy with other compounds in this fraction. However, p-coumaric acid showed potential anthelmintic effects against the larval stage of H. contortus.


Assuntos
Anti-Helmínticos/isolamento & purificação , Anti-Helmínticos/farmacologia , Fracionamento Químico/métodos , Fabaceae/química , Haemonchus/efeitos dos fármacos , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Animais , Larva/efeitos dos fármacos , Óvulo/efeitos dos fármacos , Folhas de Planta/química
20.
Environ Monit Assess ; 191(7): 414, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31168663

RESUMO

We investigated the distribution of different fractions of eight heavy metals (Zn, Cr, Cu, Pb, Cd, Ni, Fe, and Mn) in the bed sediment of the Ganga River. The study was conducted during summer low flow (March to June 2017) considering a 285-km middle stretch of the Ganga River between the Allahabad upstream and the Varanasi downstream. To assess the metal levels from a toxicological perspective, we tested the relationships between metals and sediment microbial/extracellular enzyme activities. Most of the metals showed a large fraction in residual form. However, Zn, Pb, and Cd showed about 20-30% share in the exchangeable form. The total metal concentration poorly reflected the toxicity but the exchangeable fractions did show strong negative correlations (r = - 0.83 to - 0.63; p < 0.01) with microbial/enzyme activities. Also, the nutrients and organic carbon showed strong positive correlations (r = 0.62 to 0.89; p < 0.001) with microbial/enzyme activity. The phosphate showed a strong negative correlation (r = -0.82; p < 0.001) with alkaline phosphatase. The principal component analysis (PCA) and the indices such as contamination factor (CF), enrichment factor (EF), pollution load index (PLI), geoaccumulation index (Igeo), and risk assessment code (RAC) revealed moderate to severe contamination with strong anthropogenic influence. As per the United States Environmental Protection Agency, the metal concentrations at many locations were in the highly toxic range. The study has relevance from a toxicological perspective and for the management of the Ganga River.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Poluição Química da Água/análise , Fracionamento Químico/métodos , Índia , Medição de Risco , Rios/química , Estações do Ano
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