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1.
São Paulo; s.n; s.n; 2022. 166 p. tab, graf, ilus.
Tese em Português | LILACS | ID: biblio-1416533

RESUMO

O organogel é formado por uma matriz tridimensional composta de filamentos que se auto-organizam em uma rede entrelaçada e que, por seu tipo de estrutura, pode ser utilizado com o objetivo de atuar como um implante que se forma in situ, sendo capaz de se comportar como uma forma farmacêutica de liberação prolongada. Esse trabalho tem, por tanto, o objetivo desse trabalho foi desenvolver, caracterizar, quantificar e traçar perfis de dissolução para formulações de organogel contendo meloxicam como principio ativo. O material está dividido em quatro capítulos, sendo apresentada inicialmente (I) revisão da literatura a respeito da lecitina de origem vegetal, com suas principais fontes de obtenção, como soja, girassol e colza, e também seu uso farmacêutico na obtenção de formulações como organogéis, microemulsões e lipossomas. Os demais capítulos abordam (II) desenvolvimento e otimização de uma formulação de organogel contendo lecitina de soja e Pluronic® F-127 como formadores da matriz tridimensional e meloxicam como principio ativo. (III) Desenvolvimento e validação de um método de quantificação do teor de meloxicam por cromatografia líquida de alta eficiência (CLAE). (IV) Desenvolvimento de um método de dissolução para formulações de organogel, que fosse capaz de ser utilizado na caracterização do perfil de dissolução de diferentes formulações. Com os resultados obtidos, foi possível desenvolver formulações de organogel contendo lecitina de soja, Pluronic® F-127 e meloxicam, assim como um método analítico validado para as analises de teor. Por fim, foram obtidos também os perfis de dissolução de duas formulações mais promissoras


Organogels are formed by a three-dimensional matrix composed of filaments that selforganize in an interlaced network and that, due to its type of structure, can be used with the objective of acting as an implant that forms in situ, being able to behave as an extendedrelease dosage form. This work has, therefore, the objective of this work was to develop, characterize, quantify and trace dissolution profiles for organogel formulations containing meloxicam as active ingredient. The material is divided into four chapters, initially presented (I) review of the literature on lecithin of plant origin, with its main sources of production, such as soybean, sunflower and rapeseed, and also its pharmaceutical use in obtaining formulations such as organogels , microemulsions and liposomes. The remaining chapters address (II) development and optimization of an organogel formulation containing soy lecithin and Pluronic® F-127 as three-dimensional matrix formers and meloxicam as an active ingredient. (III) Development and validation of a method for quantification of meloxicam content by high performance liquid chromatography (HPLC). (IV) Development of a dissolution method for organogel formulations, capable of being used to characterize the dissolution profile of different formulations. With the results obtained, it was possible to develop organogel formulations containing soy lecithin, Pluronic® F-127 and meloxicam, as well as a validated analytical method for content analysis. Finally, the dissolution profiles of two more promising formulations were also obtained


Assuntos
Preparações Farmacêuticas/análise , Médicos Veterinários , Drogas Veterinárias/análise , Poloxâmero/análise , Dissolução , Lecitinas/análise , Meloxicam/antagonistas & inibidores , Farmacêuticos/classificação , Química Farmacêutica/instrumentação , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida/métodos , Formas de Dosagem , Métodos
2.
J Mass Spectrom ; 56(4): e4629, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32767454

RESUMO

A new atmospheric pressure ionization method, plasmaspray ionization, termed as PSI, was developed to be an alternative ambient ion source for mass spectrometry. It comprises a plasma jet device and a sample spray part. While the nonthermal plasma jet strikes the surface of stainless steel tube out of the spray capillary, the sprayed sample will be ionized with the assistant of auxiliary gas. Although PSI is a little bit more complex than electrospray ionization (ESI) in instrument, it shows both better linearity and higher sensitivity for organic compounds. For protein samples, it presents wider distributions of multiply charged ions and higher mass resolution without sacrificing any sensitivity. For the mechanism of PSI, the charge build-up process on the tip of capillary should play a key role for the ion formation, and the stimulated pulsed voltage on the flow tube will promote the ion aggregation speed until the charge density is high enough. PSI source contains the features of plasma ionization and ESI and can be considered as a novel combo bridging these techniques. These results reflect that this method of PSI can be applied and further developed as a versatile new ion source for a wild range of organic and biological samples.


Assuntos
Espectrometria de Massas/instrumentação , Espectrometria de Massas/métodos , Compostos Orgânicos/análise , Proteínas/análise , Ionização do Ar , Pressão Atmosférica , Cafeína/análise , Lecitinas/análise , Polímeros/análise , Propilenoglicóis/análise , Reserpina/análise
3.
Food Chem ; 314: 126173, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31954942

RESUMO

The detection of phospholipids oxidation is important for meat control and disease prevention. In this paper, a photoelectrochemical sensor based on printable mesoscopic chip (PMC) for fast and real-time monitoring phospholipids oxidation was designed and fabricated. TiO2, ZrO2 and carbon films of PMC were screen-printed onto the FTO glass layer by layer. The PMC and the feasibility for determination of phospholipids oxidation were investigated by scanning electron microscope (SEM), UV-vis spectroscopy, cyclic voltammograms (CVs) and electrochemical impedance spectroscopy (EIS), etc. The short circuit current (Jsc) was used as a signal current, which would decrease if phospholipids in PMC were undergoing oxidation for the change of electrical properties. Compared with other methods, phospholipids in PMC did not require pretreatment, and the process was nondestructive and real-time. Meanwhile, this method showed high sensitivity and good selectivity. The fabricating process of PMC is simple, and the costs are low, relatively.


Assuntos
Espectroscopia Dielétrica/instrumentação , Análise de Alimentos/instrumentação , Fosfolipídeos/análise , Carbono/química , Espectroscopia Dielétrica/métodos , Desenho de Equipamento , Análise de Alimentos/métodos , Lecitinas/análise , Lecitinas/química , Microscopia Eletrônica de Varredura , Oxirredução , Fosfolipídeos/química , Sensibilidade e Especificidade , Titânio/química
4.
J Clin Lab Anal ; 34(4): e23109, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31804000

RESUMO

BACKGROUND: The pulmonary surfactant especially lipids in amniotic fluid can reflect the development stage of fetal lung maturity (FLM). However, the conventional lecithin/sphingomyelin (L/S) ratio method by thin layer chromatography (TLC) is insufficient and inconvenient for FLM prediction in clinical practice. METHODS: The amniotic fluid samples were collected from the pregnant women in labor or undergoing amniocentesis and analyzed for its lipid contents with the liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) method and the lamellar body count (LBC) method. To reveal the lipidomic profiling of different FLM stages, three groups of amniotic fluid samples including 8 from premature group (gestational week (GW) < 37), 10 from mature group (GW < 37), and 10 from mature group (GW > 38) were compared with the control group (n = 6) of 18 GWs separately. RESULTS: In the FLM prediction study, the sensitivity of the LC-HRMS method and LBC method was 91% and 73%, respectively; the specificity was 100% and 95%, respectively. The most significant metabolic pathway was linoleic acid metabolism between the premature group and the control group. Both glycerophospholipid metabolism and glycosylphosphatidylinositol-anchor biosynthesis were enriched in the mature groups. In search of potential FLM prediction markers in amniotic fluid, 8 phosphatidylcholines, 1 sphingomyelin, and 1 phosphatidylethanolamine were significantly increased in the mature groups compared with the premature group. CONCLUSION: An efficient LC-HRMS method for L/S ratio in predicting FLM was established. The linoleic acid metabolism may play an important role in the fetal lung development.


Assuntos
Líquido Amniótico/metabolismo , Maturidade dos Órgãos Fetais/fisiologia , Lipidômica/métodos , Pulmão/embriologia , Espectrometria de Massas/métodos , Amniocentese , Biomarcadores/análise , Cromatografia Líquida/métodos , Feminino , Humanos , Lecitinas/análise , Metabolismo dos Lipídeos , Gravidez , Reprodutibilidade dos Testes , Esfingomielinas/análise
5.
Analyst ; 144(16): 4826-4834, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31290490

RESUMO

This study demonstrates a unique strategy for enhancing infrared (IR) spectroscopic discrimination between gall bladder (GB) polyps and cancer. This strategy includes the separation of raw bile juice into three sections of organic, aqueous, and amphiphilic phases and a cooperative combination of all IR spectral features of each separated phase for the discrimination. Raw bile juice is viscous and complex in composition because it contains fatty acids, cholesterol, proteins, phospholipids, bilirubin, and other components; therefore, the acquisition of IR spectra providing more component-discernible information is fundamental for improving discrimination. For this purpose, raw bile juice was separated into an aqueous phase, mostly containing bile salts, an organic phase with isolated lipids, and an amphiphilic phase, mainly containing proteins. The subsequent IR spectra of each separated phase were mutually characteristic and complementary to each other. When all the IR spectral features were combined, the discrimination was improved compared to that using the spectra of raw bile juice with no separation. The cooperative integration of more component-specific spectra obtained from each separated phase enhanced the discrimination. In addition, the IR spectra of the major constituents in bile juice, such as bile acids, conjugated bile salts, lecithin, and cholesterol, were recorded to explain the IR features of each separated phase.


Assuntos
Bile/química , Neoplasias da Vesícula Biliar/diagnóstico , Pólipos/diagnóstico , Ácidos e Sais Biliares/análise , Colesterol/análise , Diagnóstico Diferencial , Vesícula Biliar , Humanos , Lecitinas/análise , Análise de Componente Principal , Espectrofotometria Infravermelho/métodos
6.
J Sci Food Agric ; 99(12): 5586-5593, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31152446

RESUMO

BACKGROUND: Mono-, di- and oligosaccharides, polyhydric alcohols and lipids are three main types of plasticizers used to process food materials. In the present study, inulin, maltitol and lecithin were selected as representative oligosaccharide, polyhydric alcohol and lipid fat replacers, respectively. Their effects on the physicochemical properties of reduced-fat mozzarella cheese were evaluated. RESULTS: Lecithin reduced the hardness and increased the degree of free oil released. Inulin and lecithin decreased the hydrophobic interaction of reduced-fat cheese. Maltitol improved the elasticity of the reduced-fat cheese and increased the hydrophobic interaction within the casein matrix. Maltitol-added cheese had a lower glass transition temperature (Tg ) than the other cheeses. Maltitol significantly improved the stretchability of the reduced-fat cheese. CONCLUSION: The results obtained in the present study suggest that maltitol is an effective fat replacer in reduced-fat mozzarella cheese and might enhance the cheese's functional properties. The Tg of cheese was related to the water and fat content, fat replacer addition and cross-linking degree of casein. The relationship between Tg and the physicochemical properties of cheese will be studied in further research. © 2019 Society of Chemical Industry.


Assuntos
Queijo/análise , Substitutos da Gordura/análise , Aditivos Alimentares/análise , Inulina/análise , Lecitinas/análise , Maltose/análogos & derivados , Plastificantes/análise , Álcoois Açúcares/análise , Animais , Caseínas/análise , Bovinos , Manipulação de Alimentos , Dureza , Maltose/análise
7.
Food Chem ; 279: 216-222, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30611483

RESUMO

The effects of amphiphilic compounds on the dielectric constant of bulk oils were determined and the utility of the dielectric constant as a reliable parameter for predicting the oxidative stability of edible oils was evaluated. As the content of monoacylglycerols (MAGs), lecithin, and moisture increased, the dielectric constant of modified corn oil increased at different rates, whereas the addition of free fatty acids, including oleic and linoleic acid, decreased the dielectric constant of modified corn oil. Unoxidized fresh bulk oils showed a wide range of dielectric constants, from 8 for canola oils to 33 for flaxseed oils. The dielectric constant showed a strong correlation with the percentage of unsaturated fatty acids in the bulk oils. Oils with low oxidative stability had a high dielectric constant. Overall, the dielectric constant of bulk oils is strongly correlated with the content of amphiphilic compounds, moisture content, and degree of unsaturation of fatty acids.


Assuntos
Ácidos Graxos não Esterificados/análise , Óleos de Plantas/química , Antioxidantes/química , Óleo de Milho/química , Ácidos Graxos não Esterificados/química , Lecitinas/análise , Lecitinas/química , Ácido Linoleico/análise , Ácido Linoleico/química , Óleo de Semente do Linho/química , Monoglicerídeos/análise , Monoglicerídeos/química , Oxirredução
8.
AAPS PharmSciTech ; 20(3): 97, 2019 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-30694405

RESUMO

This work is devoted to design a novel nanostructured hybrid vesicle (NHV) made of lecithin and an acrylate/C10-C30 alkyl acrylate for the nasal delivery of a model active indomethacin (IND), and further to probe its microstructure, intermolecular interactions, drug release behavior, ex vivo permeation, and stability. NHVs were prepared by cavitation technology employing RSM-based central composite design (CCD). Amount of lecithin (X1), power of ultrasound (X2), and sonication time (X3) were selected as three independent variables while the studied response included Z-Avg (nm), polydispersity index (PDI), and zeta potential (mV). The designed system (NHV) was investigated through dynamic (DLS) and electrophoretic light scattering (ELS), attenuated total reflectance (ATR-FTIR), oscillatory measurement (stress and frequency sweep), and transmission electron microscopy (TEM). CCD was found useful in optimizing NHV. An optimized formulation (S6) had Z-Avg 80 nm, PDI 0.2, and zeta potential of - 43.26 mV. Morphology investigation revealed spherical vesicles with smaller TEM diameters (the largest particle being 52.26 nm). ATR analysis demonstrated significant intermolecular interactions among the drug (IND) and the components of vesicles. The designed vesicles had an elastic predominance and displayed supercase II (n > 1) type of drug release. Besides, the vesicles possessed potential to transport IND across the nasal mucosa with the steady-state flux (µg/cm2/h) and permeability coefficient (cm/h) of 26.61 and 13.30 × 10-3, respectively. NHV exhibited an exceptional stability involving a combination of electrostatic and steric interactions while the histopathology investigation confirmed their safety for nasal administration.


Assuntos
Anti-Inflamatórios não Esteroides/administração & dosagem , Indometacina/administração & dosagem , Administração Intranasal , Animais , Anti-Inflamatórios não Esteroides/química , Indometacina/química , Lecitinas/análise , Microscopia Eletrônica de Transmissão , Mucosa Nasal/metabolismo , Tamanho da Partícula , Permeabilidade , Ovinos , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
9.
Biosensors (Basel) ; 8(3)2018 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-30087280

RESUMO

A theoretical analysis and computational study of biomaterial sample detection with surface plasmon resonance (SPR) phenomenon spectroscopy are presented in this work with the objective of achieving more sensitive detection. In this paper, a Fe3O4@Au core-shell, a nanocomposite spherical nanoparticle consisting of a spherical Fe3O4 core covered by an Au shell, was used as an active material for biomaterial sample detection, such as for blood plasma, haemoglobin (Hb) cytoplasm and lecithin, with a wavelength of 632.8 nm. We present the detection amplification technique through an attenuated total reflection (ATR) spectrum in the Kretschmann configuration. The system consists of a four-layer material, i.e., prism/Ag/Fe3O4@Au + biomaterial sample/air. The effective permittivity determination of the core-shell nanoparticle (Fe3O4@Au) and the composite (Fe3O4@Au + biomaterial sample) was done by applying the effective medium theory approximation, and the calculation of the reflectivity was carried out by varying the size of the core-shell, volume fraction and biomaterial sample. In this model, the refractive index (RI) of the BK7 prism is 1.51; the RI of the Ag thin film is 0.13455 + 3.98651i with a thickness of 40 nm; and the RI of the composite is varied depending on the size of the nanoparticle core-shell and the RI of the biomaterial samples. Our results show that by varying the sizes of the core-shell, volume fraction and the RIs of the biomaterial samples, the dip in the reflectivity (ATR) spectrum is shifted to the larger angle of incident light, and the addition of a core-shell in the conventional SPR-based biosensor leads to the enhancement of the SPR biosensor sensitivity. For a core-shell with a radius a = 2.5 nm, the sensitivity increased by 10% for blood plasma detection, 47.72% for Hb cytoplasm detection and by 22.08% for lecithin detection compared to the sensitivity of the conventional SPR-based biosensor without core-shell addition.


Assuntos
Técnicas Biossensoriais/métodos , Hemoglobinas/análise , Lecitinas/análise , Ressonância de Plasmônio de Superfície/métodos , Simulação por Computador , Ouro/química , Ferro/química , Nanopartículas Metálicas/química
10.
Food Res Int ; 111: 168-177, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30007673

RESUMO

In this study the effect of lecithin (L) addition and solvent quality in a well-established oleogel system formed by ß-sitosterol and γ-oryzanol (BG) was investigated. Medium chain triglycerides (MCT) and sunflower oil (SFO) were used as triglycerides and hexadecane (HEX) as a model of linear hydrocarbon. Lecithin was proposed due to its natural and versatile properties, showing different functionalities such as emulsifier and co-oleogelator. A study based on hierarchical organization of structured oil was performed applying techniques for bulk, meso and nanoscale. Self-sustained structures could no longer be observed after 40 wt% of BG replacement by lecithin. Small-angle X-ray scattering showed that the formed nanostructures (building blocks) were dependent on type of solvent and BG:L ratio in the mixture of oleogelators. Differential scanning calorimetry showed that stability against temperature was improved decreasing the polarity of the oil, and a time-dependent self-assembly of hybrid systems was observed from thermal and rheological measurements. Microscopy images exhibited changes on typical fibril aggregation of BG as lecithin was added, which promoted to a certain extent the suppression of ribbons. Oscillatory shear and uniaxial compression measurements were influenced by BG:L ratio and solvent mainly at higher lecithin amount. The combination of BG and MCT appeared to be the most affected by lecithin incorporation whereas SFO rendered harder oleogels. These results could contribute to understand the role of both lecithin and solvent type influencing the host oleogelator structure. It was hypothesized that intermolecular BG complex formation is hindered by lecithin, besides this phospholipid also might coexist as a different phase, causing structural changes in the gel network. Addressing the role of co-oleogelator it can provide the opportunity to tune soft materials with adjusted properties.


Assuntos
Lecitinas/análise , Lecitinas/química , Fitosteróis/análise , Fitosteróis/química , Varredura Diferencial de Calorimetria , Cristalização , Compostos Orgânicos/análise , Compostos Orgânicos/química , Fenilpropionatos/química , Sitosteroides/química , Óleo de Girassol/síntese química , Triglicerídeos/química
11.
Food Chem ; 261: 194-200, 2018 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-29739582

RESUMO

Effects of different moisture contents and oxidised compounds on the critical micelle concentration (CMC) of lecithin were determined in bulk oils and in medium-chain triacylglycerols (MCT). CMC of lecithin in MCT was significantly higher than that in other vegetable oils including olive, soybean, corn, and rapeseed oils (p < 0.05). Presence of moisture significantly affected the CMC of lecithin in MCT (p < 0.05). CMC of lecithin was high when the moisture content was below 900 ppm, whereas at a moisture content of 1000 ppm, CMC of lecithin decreased significantly (p < 0.05), and then started to increase. Addition of total polar materials (TPM), which are oxidation products, at 3 and 5% concentrations, decreased CMC of lecithin significantly (p < 0.05) in MCT, compared to when 0, 1, and 1.5% of TPM was added to MCT. As the degree of oxidation increased in corn oil, CMC of lecithin gradually decreased. Additionally, under different moisture contents, corn oils showed a similar pattern of CMC of lecithin in MCT, whereas oxidised corn oil had a little lower CMC of lecithin than unoxidised corn oil. The results clearly showed that the concentration of lecithin for the formation of micelles is greatly influenced by the presence of oxidation products and the moisture content in bulk oils.


Assuntos
Lecitinas/análise , Óleos de Plantas/química , Triglicerídeos/química , Óleo de Milho/química , Micelas , Oxirredução , Óleo de Brassica napus/química
12.
Food Res Int ; 100(Pt 1): 541-550, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28873719

RESUMO

The effect of two-step and five-step acetone washing of soybean lecithin (SL) on compositional properties of partially purified phosphatidylcholines (PW2 and PW5) was studied. Trace amounts of protein were detected in SL, PW2 and PW5, with a predominance of glutamic acid and aspartic acid. Increasing the number of acetone washing steps significantly reduced the total content of γ-, δ- and α-tocopherol. Similar reductions (≈90%) of neutral lipids were found in both PW2 and PW5, but the removal of free fatty acids was higher in PW5 than in PW2 (78% vs. 71%). Linoleic acid was the main constituent in both the neutral lipids and the phospholipid fractions of SL, PW2 and PW5, accounting for around 53-59% of total fatty acids; however, a considerable amount of it was removed by increasing the number of washing steps. All phospholipid classes were mostly concentrated in the first two-step washing of lecithin. Further washing increased the concentration of phosphatidylcholine (PC) in PW5, as compared to PW2. Glycerol-containing liposomes from PW2 and PW5 were produced using two different-intensity sonication procedures (method A: 120W, 5min; method B: 30W, 2min) using a probe-type sonicator (100mL volume suspension). Liposomes of soy lecithin and liposomes of PW5 without glycerol were also obtained by using strong sonication (method A). The liposomal dispersion with the highest purification and the stronger sonication was clearly distinguished from the others, both in particle size and in zeta potential. DSC results showed noticeable interference of glycerol in the membrane structure, but minimal changes in particle size and surface charge.


Assuntos
Glicerol/química , Lecitinas , Lipossomos , Sonicação/métodos , Manipulação de Alimentos/métodos , Lecitinas/análise , Lecitinas/química , Lipossomos/análise , Lipossomos/química , Espectroscopia de Infravermelho com Transformada de Fourier
13.
Food Chem ; 230: 241-249, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28407907

RESUMO

To enhance storage life and post-storage quality of fresh goji berries, three treatments with lecithin (1, 5, 10g·L-1) and two storage times (8, 16days) were evaluated. The significant effects on the physiological and biochemical parameters were varied. 1g·L-1 lecithin showed its main effects after 8days of storage by reduction in total weight loss and decay, SSC/TA ratio (also at 16days), and chlorophyll content and with highest scores of sensory attributes (also at 16days). 5g·L-1 lecithin showed its main effects after 16days of storage: highest SSC, highest TA (also at 8days), highest TPC, only significant reduction in DPPH antioxidant activity, and highest total flavonoid content. 10g·L-1 lecithin showed its main effects after 8days of storage with highest SSC, chlorophyll content, total flavonoid, DPPH, and ABTS antioxidant activity (also at 16days), but with least scores of sensory attributes.


Assuntos
Antioxidantes/química , Frutas/química , Lecitinas/química , Lycium/química , Antioxidantes/análise , Armazenamento de Alimentos , Lecitinas/análise , Oxirredução
14.
Appl Environ Microbiol ; 83(8)2017 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-28213539

RESUMO

Lecithin is a natural emulsifier used in a wide range of food and nonfood applications to improve physical stability, with no known bioactive effects. In this study, the effect of lecithin on the antimicrobial performance of a constant eugenol concentration was tested against three Escherichia coli strains (C600, 0.1229, and O157:H7 strain ATCC 700728). This is the first study, to our knowledge, focusing on lecithin at concentrations below those commonly used in foods to improve the stability of oil in water emulsions (≤10 mg/100 ml). For all three cultures, significant synergistic antimicrobial effects were observed when E. coli cultures were exposed to a constant eugenol concentration (ranging from 0.043 to 0.050% [wt/wt]) together with critical lecithin concentrations ranging from 0.5 to 1 mg/100 ml. Increasing the concentration of lecithin above 1 mg/100 ml (up to 10 mg/100 ml lecithin) diminished the antibacterial effect to values similar to those with eugenol-only treatments. The formation of aggregates (<100 nm) at the critical lecithin concentration was observed using cryo-transmission electron microscopy (cryo-TEM), together with a reduction in light absorbance at 284 nm. At critically low concentrations of lecithin, the formation of nanoscale aggregates is responsible for improving eugenol antimicrobial effects.IMPORTANCE Essential oils (EOs) are effective natural antimicrobials. However, their hydrophobicity and strong aromatic character limit the use of essential oils in food systems. Emulsifiers (e.g., lecithin) increase the stability of EOs in water-based systems but fail to consistently improve antimicrobial effects. We demonstrate that lecithin, within a narrow critical concentration window, can enhance the antimicrobial properties of eugenol. This study highlights the potential bioactivity of lecithin when utilized to effectively control foodborne pathogens.


Assuntos
Anti-Infecciosos/farmacologia , Escherichia coli O157/efeitos dos fármacos , Eugenol/farmacologia , Microbiologia de Alimentos , Lecitinas/análise , Contagem de Colônia Microbiana , Emulsões , Testes de Sensibilidade Microbiana , Óleos Voláteis/farmacologia
15.
Food Chem ; 225: 162-166, 2017 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-28193410

RESUMO

This paper presents a method for determining phospholipids in soybean lecithin samples by phosphorus determination using high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) via molecular absorption of phosphorus monoxide. Samples were diluted in methyl isobutyl ketone. The best conditions were found to be 213.561nm with a pyrolysis temperature of 1300°C, a volatilization temperature of 2300°C and Mg as a chemical modifier. To increase the analytical sensitivity, measurement of the absorbance signal was obtained by summing molecular transition lines for PO surrounding 213nm: 213.561, 213.526, 213.617 and 213.637nm. The limit of detection was 2.35mgg-1 and the precision, evaluated as relative standard deviation (RSD), was 2.47% (n=10) for a sample containing 2.2% (w/v) phosphorus. The developed method was applied for the analysis of commercial samples of soybean lecithin. The determined concentrations of phospholipids in the samples varied between 38.1 and 45% (w/v).


Assuntos
/química , Lecitinas/análise , Fosfolipídeos/análise , Fósforo/análise , Espectrofotometria Atômica/métodos , Grafite , Temperatura
16.
Food Chem ; 220: 115-122, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-27855878

RESUMO

In present study, nanoliposomes were prepared by thin hydration method with different concentrations of phenolic compounds (500, 750 and 1000ppm) of pure extract and lecithin (1, 2 and 3%w/w) and characterized by considering the particle size, polydispersity index (PDI), zeta potential, encapsulation efficiency (EE) and morphology. The results showed that nanoliposome (90.39-103.78nm) had negative surface charge varied from -51.5±0.9 to -40.2±0.2mV with a narrow size distribution (PDI≈0.069-0.123). Nanoliposomes composed of 1% lecithin with 1000ppm of phenolic compounds had the highest EE (52.93%). The FTIR analysis indicated the formation of hydrogen bonds between the polar zone of phospholipid and the OH groups of phenolic compounds. Phenolic compounds also increased phase transition temperature (Tc) of nanoliposomes (2.01-7.24°C). Moreover, nanoliposomes had considerable stability during storage. Consequently, liposome is an efficient carrier for protection and improving PGHE biofunctional actives in foodstuffs.


Assuntos
Lipossomos/química , Nozes/química , Fenóis/análise , Pistacia/química , Extratos Vegetais/análise , Antocianinas/análise , Varredura Diferencial de Calorimetria , Flavonoides/análise , Lecitinas/análise , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Oxirredução , Tamanho da Partícula , Transição de Fase , Extração em Fase Sólida , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
17.
Indian J Gastroenterol ; 35(5): 347-353, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27633032

RESUMO

BACKGROUND: Gallstones (GS) in south India (SI) are predominantly pure pigment or mixed, while in North India (NI), these are either pure cholesterol or mixed. While cholesterol rich gallbladder (GB) bile predicts cholesterol GS, constituent of bile in primary pigment GS is not known. We compared the composition of GB bile from healthy liver donors and patients with GS from north and south India. METHODS: Gallbladder bile from healthy liver donors from north (10) and south India (8) served as controls. Cases were patients from north (21) and south India (17) who underwent cholecystectomy for GS disease. Gallbladder bile from both cases and controls was analyzed for cholesterol, lecithin (phospholipid), and bile salts. Gallstones were classified as cholesterol, mixed, and pigment based on morphology and biochemical analysis. RESULTS: The median cholesterol concentration in control bile from north was significantly high compared to south (p<0.001) with no difference in lecithin and bile salts (p NS). Except for one sample each from north and south, the cholesterol solubility of controls was within the critical micellar zone. Mixed GS were most frequent in north India (61.9 %) while pigment GS dominated in south (61.9 %). The median cholesterol concentration in bile samples of cholecystectomy patients from north India was significantly high GS (p < 0.00001) with significant lowering of bile salts and lecithin (p < 0.00001). In south India, patients with mixed GS had high cholesterol content in bile compared to controls and patients with pigment GS; bile in latter had significantly higher concentration of bile salt compared to controls and mixed GS. The ternary plot confirmed the composition of GB bile from north and south India. CONCLUSIONS: Gallbladder bile in controls and patients with GS from north India had significantly high cholesterol concentration. In south India, patients with mixed GS had cholesterol rich bile while pigment GS had higher concentrations of bile salts.


Assuntos
Ácidos e Sais Biliares/análise , Bile/química , Bile/metabolismo , Colesterol/análise , Vesícula Biliar/metabolismo , Cálculos Biliares/química , Cálculos Biliares/metabolismo , Lecitinas/análise , Cálculos Biliares/classificação , Humanos , Índia
18.
J Dairy Sci ; 99(9): 6948-6960, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27344387

RESUMO

Whey protein phospholipid concentrate (WPPC) and delactosed permeate (DLP) are 2 coproducts of cheese whey processing that are currently underutilized. Past research has shown that WPPC and DLP can be used together as a functional dairy ingredient in foods such as ice cream, soup, and caramel. However, the scope of the research has been limited to a single WPPC supplier. The variability of the composition and functionality of WPPC was previously studied. The objective of this research was to expand on the previous study and examine the potential applications of WPPC and DLP blends in foods. In ice cream, WPPC was added as a natural emulsifier to replace synthetic emulsifiers. The WPPC decreased the amount of partially coalesced fat and increased the drip-through rate. In caramel, DLP and WPPC replaced sweetened condensed skim milk and lecithin. Cold flow increased significantly, and hardness and stickiness decreased. In cake, DLP and WPPC were added as a total replacement of eggs, with no change in yield, color, or texture. Overall, WPPC and DLP can be utilized as functional dairy ingredients at a lower cost in ice cream and cake but not in chewy caramel.


Assuntos
Laticínios/análise , Manipulação de Alimentos , Sorvetes/análise , Fosfolipídeos/análise , Proteínas do Soro do Leite/química , Animais , Queijo/análise , Colorimetria , Análise de Alimentos , Lecitinas/análise , Leite/química , Viscosidade
19.
J Agric Food Chem ; 64(28): 5686-91, 2016 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-27329567

RESUMO

Sterol bioaccessibility (BA) of three plant sterol (PS)-enriched milk-based fruit beverages (MFb) with different fat contents (1.1-2.4%), lipid sources (animal or vegetable), and without or with emulsifiers (whey proteins enriched with milk fat globule membrane (MFGM) or soy lecithin) was evaluated after simulated gastrointestinal digestion. The BA of total PS followed the order 31.4% (MFbM containing milk fat and whey proteins enriched with MFGM) = 28.2% (MFbO containing extra virgin olive oil and soy lecithin) > 8.7% (MFb without fat addition). Total and individual PS content in the bioaccessible fractions followed the order MFbM > MFbO > MFb. Consequently, formulation with MFGM is proposed in beverages of this kind to ensure optimum bioavailability of PS. Our results suggest that the BA of PS is influenced by the type and quantity of fat and the emulsifier type involved.


Assuntos
Bebidas/análise , Lipídeos/química , Leite/química , Fitosteróis/química , Animais , Bovinos , Digestão , Emulsificantes/análise , Emulsificantes/metabolismo , Frutas/química , Trato Gastrointestinal/metabolismo , Glicolipídeos/análise , Glicolipídeos/metabolismo , Glicoproteínas/análise , Glicoproteínas/metabolismo , Lecitinas/análise , Lecitinas/metabolismo , Gotículas Lipídicas , Fitosteróis/metabolismo
20.
Artigo em Inglês | MEDLINE | ID: mdl-26305412

RESUMO

OBJECTIVE: To compare the influence of the obstetrical condition on neonatal respiratory performance, to estimate surfactant synthesis through lecithin and sphingomyelin ratio (L/S) in amniotic fluid of pregnant bitches and correlate the L/S with the respiratory condition during the first hour of life. DESIGN: Prospective randomized study. SETTING: University veterinary teaching hospital and private referral centers. ANIMALS: In accordance to the condition at birth, puppies from 25 healthy bitches aged 2-6 years were allocated into: Eutocia Group--EUT (n = 19 neonates and 14 bitches); Dystocia Group--DYS (n = 8 neonates and 5 bitches) and Elective Cesarean Section Group--CS (n = 12 neonates and 11 bitches). INTERVENTIONS: Amniotic fluid was drawn from amniotic sac and lecithin (L) and sphingomyelin (S) were measured by high performance liquid chromatography to obtain the L/S ratio. Neonatal physical examination was performed at 1, 5, and 60 minutes after delivery, and included the assessment of respiratory rate (RR) and respiration effort (RE). MEASUREMENTS AND MAIN RESULTS: CS group had significantly lower amniotic L/S ratio when compared to EUT and DYS. There were no significant differences between vaginal groups (EUT versus DYS) in respect to L/S ratios. RE of eutocic neonates improved promptly, while RE of DYS and CS groups improved only 1 hour following birth. Moreover, amniotic L/S ratio positively correlated with RR after 60 minutes. CONCLUSIONS: We identified a possible influence of the delivery method on the final surfactant maturation process. Thus, neonates born by elective CS prior to the onset of expulsive uterine contractions should have their respiratory parameters carefully monitored. Additionally, we propose that assessment of respiratory parameters 1 hour following birth can serve as a practical means to indirectly estimate pulmonary maturation (ie, surfactant synthesis) in puppies.


Assuntos
Líquido Amniótico/química , Animais Recém-Nascidos/fisiologia , Cães/fisiologia , Lecitinas/análise , Respiração , Esfingomielinas/análise , Animais , Cesárea/veterinária , Distocia/veterinária , Feminino , Pulmão/fisiologia , Gravidez , Estudos Prospectivos
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