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1.
Int J Biol Macromol ; 185: 287-296, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34153359

RESUMO

Cellulose microcrystalline (MCC) was widely used in pharmaceutical and chemical industries because of its low degree of polymerization and large specific surface area. As its modified form, dialdehyde cellulose (DAC) was used for cross-linking and immobilizing Rhizopus lipase together with magnetic nanoparticles (MNPs) due to its active aldehyde groups. In this study, in order to maintain the original enzyme activity as much as possible and improve the stability of lipase, the Rhizopus lipase was successfully immobilized on the magnetic dialdehyde cellulose nanoparticles (MDC). Specifically, the immobilization conditions including dosage of DAC, concentration of enzyme, immobilization time and temperature together with pH value of the reaction medium were optimized. Maximum immobilization yield (60.03 ± 0.49%) and recovery activity (88.88 ± 0.61%) can be obtained under the optimal process conditions. The changes in secondary structures of immobilized enzyme revealed the increment in conformational rigidity, which can be reflected in temperature and pH stability as well as tolerance of organic reagents. Additionally, the recovery activity of immobilized enzyme still reached 50.60 ± 0.59% after 30 d of storage and 52.10 ± 0.57% retained after 6 cycles. These results indicated the ideal application prospect of MDC in immobilized enzymes.


Assuntos
Celulose/análogos & derivados , Lipase/química , Nanopartículas de Magnetita/química , Rhizopus/enzimologia , Celulose/química , Estabilidade Enzimática , Enzimas Imobilizadas/química , Proteínas Fúngicas/química , Concentração de Íons de Hidrogênio , Estrutura Secundária de Proteína , Temperatura , Tempo
2.
J Sep Sci ; 44(4): 922-930, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33284511

RESUMO

Ondansetron, a highly selective 5-hydroxytryptamine 3 receptor antagonist, was successfully enantioseparated by recycling countercurrent chromatography using sulfobutyl ether-ß-cyclodextrin as chiral selector. Important factors for the enantioseparation were optimized, including different organic solvent, type of substituted ß-cyclodextrin, pH of aqueous phase, concentration of chiral selector, and separation temperature. A biphasic solvent system composed of n-hexane: n-butyl acetate: 0.1 mol/L phosphate buffer solution pH 9.2 with 50 mmol/L of sulfobutyl ether-ß-cyclodextrin (2.5:7.5:10, v/v/v) was selected. Under optimized separation conditions, 5 mg of ondansetron was enantioseparated using recycling countercurrent chromatography, yielding 1.2 and 1.5 mg of ondansetron enantiomers with 97.5 and 95.8% purity and the recovery reached 48-60%.

3.
Biotechnol Lett ; 42(11): 2157-2167, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32661656

RESUMO

OBJECTIVE: To evaluate the catalytic esterification performance of proteases in micro-aqueous systems and to study the suitable conditions for maintaining protease activity. RESULTS: It was found that the protease showed better enzyme catalytic activity in the micro-aqueous phase containing 4% boric acid-borax buffer than that of the pure organic phase. The protease activity was easily activated by 0.20 M boric acid-borax buffer, and the enzyme activity was still high for a long time in alkaline environment (pH 8.40-9.60) and under the temperature of 40-55 °C. Experiments using protease and Candida lipase to synthesize sucrose-6-ethyl ester showed that protease had better esterification activity than Candida lipase in the micro-aqueous phase.

4.
Carbohydr Polym ; 241: 116349, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32507176

RESUMO

In order to reveal the relationship between the degree of crosslinking and the properties of chitosan nanoparticles, a potassium polyvinyl sulfate (PVSK) titration method was established for the determination of free amino group in chitosan, which showed that there was a window effect in the crosslinking degree and particle size of three kinds of molecular weight chitosan cross-linked by different content of tripolyphosphate (TPP), and the nanoparticles with moderate crosslinking degree were smaller. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) showed the moderate degree of cross-linking nanoparticles had strong antibacterial properties. IR analysis showed that the interaction between chitosan nanoparticles with different crosslinking degree and TPP were different. X-ray diffraction analysis showed that the cross-linked chitosan nanoparticles were amorphous. Above all, the crosslinking degree of TPP cross-linked chitosan nanoparticles was related to the particle size and antibacterial properties.


Assuntos
Antibacterianos , Quitosana/análogos & derivados , Nanopartículas/química , Antibacterianos/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Quitosana/química , Quitosana/farmacologia , Reagentes para Ligações Cruzadas
5.
Int J Biol Macromol ; 160: 429-436, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32464204

RESUMO

In order to develop starch hemostatic materials with excellent hemostatic properties, the preparation of crosslinked porous starch (SPS) with sodium trimetaphosphate (STMP) as cross-linking agent was studied in this paper. When the solid-liquid ratio of porous starch (PS) was 30%, the mass ratio of cross-linking agent to starch was 0.04-1, and the SPS was crosslinked at pH 10.0, 55 °C for 50-60 min, the water absorption ratio and swelling ratio of SPS reach up to 160.5% and 239.1%, respectively. The characterization by infrared spectra, scanning electron microscopy and X-Ray diffraction spectra confirmed that the structure of SPS is similar to that of PS. The degradation experiment in vitro indicated that the degradation effect of PS was better than that of SPS. The whole blood coagulation kinetics experiment showed that SPS could promote the formation of blood clot, and the adsorption experiment of red blood cells in vitro showed that SPS could adsorb red blood cells. The average hemostasis time of SPS in tail amputation 1 cm and liver laceration were 181.03 s and 179.30 s.


Assuntos
Hemostáticos/química , Amido/química , Adsorção , Coagulação Sanguínea/efeitos dos fármacos , Hemostasia/efeitos dos fármacos , Hemostáticos/farmacologia , Cinética , Microscopia Eletrônica de Varredura/métodos , Polifosfatos/química , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Água/química , Difração de Raios X/métodos
6.
J Nanosci Nanotechnol ; 20(10): 6168-6172, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32384967

RESUMO

To explore the hydrolyzed properties of nano-SiO2 immobilized porcine pancreatic lipase, the selective hydrolysis of immobilized lipase for glycidyl butyrate was compared with the free enzyme. The hydrolysis selectivity of the immobilized biocatalyst was evaluated and compared with the free enzyme using the enantiomeric excess (ee) of resolving racemic glycidyl butyrate as the indicator. The enantiomeric excess of the immobilized biocatalyst could be increased by 4.5%-10.0% which compared with the free enzyme under every single technological condition. The ee was improved from 84.7% for free enzyme to 91.6% for the immobilized enzyme with 61.2% conversion. Compared with free enzyme, the conversion rate of the immobilized enzyme was increased slightly, but the % enantiomeric excess of the immobilized enzyme was increased greatly.


Assuntos
Butiratos , Lipase , Animais , Estabilidade Enzimática , Enzimas Imobilizadas/metabolismo , Concentração de Íons de Hidrogênio , Dióxido de Silício , Suínos , Temperatura
7.
Int J Biol Macromol ; 139: 740-751, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31377290

RESUMO

Frontal affinity chromatography (FAC) combined with enzyme has been widely used for drug screening. In this paper, the effect of target enzyme activity on screening of bioactive compounds was studied through applying FAC. Trypsin with different degree of inactivation were prepared as target enzyme by thermal denaturation. Their primary structure was identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and use Fourier transform infrared (FTIR) and ultraviolet-visible (UV-vis) spectroscopy to detect group structure. Ultimately, it was found that the main structure of enzyme with decreased activity remained unchanged. The oxymatrine and matrine which can interact with trypsin were selected to study their binding to trypsin with different activities in FAC. The results showed that oxymatrine and matrine had a significant difference in the breakthrough volume among seven kinds of columns prepared by trypsins with different activities, at the different concentration. It indicated that trypsins with different activities in FAC could combine with oxymatrine and matrine. The binding constant (Kd) variation between oxymatrine, matrine and trypsin with different activities are 5.520 ±â€¯0.038 and 3.577 ±â€¯0.071, within error range, which indicated that the activity of target enzyme with primary unchanged structure has no effect on screening of bioactive components by FAC.


Assuntos
Cromatografia de Afinidade , Tripsina/química , Alcaloides/química , Engenharia Genética , Glicerol/química , Temperatura Alta , Cinética , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Varredura , Peptídeos/química , Quinolizinas/química , Silanos/química , Solventes/química , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier
8.
Carbohydr Polym ; 218: 324-332, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31221337

RESUMO

Dialdehyde starch (DAS) is a kind of modified starch which contains many active aldehyde groups and has good biocompatibility. In this study, magnetic dialdehyde starch nanoparticles were successfully used to immobilize lipase. The lipase was immobilized onto magnetic nanoparticles by using DAS instead of glutaraldehyde as a crosslinker. The parameters like DAS dosage, enzyme concentration and immobilization time were optimized. Enzymatic properties studies exhibited that after DAS cross-linking, the storage stability of the immobilized enzyme reached 82.5%, and the recycling rate reached 53.6%, whereas in case of glutaraldehyde cross linker, it was 79.4% and 46.8%, the former also exhibited better stability and durability. Compared with the free enzyme, the immobilized enzyme indicated higher acid-base tolerance and thermal stability, and had good enzymatic properties. Magnetic dialdehyde starch nanoparticles may have application prospects as an excellent enzyme carrier, which provides a reference for the preparation of other immobilized enzymes with excellent performance.


Assuntos
Hidrolases de Éster Carboxílico/química , Reagentes para Ligações Cruzadas/química , Enzimas Imobilizadas/química , Nanopartículas de Magnetita/química , Amido/análogos & derivados , Ensaios Enzimáticos , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Oxirredução , Ácido Periódico/química , Rhizopus/enzimologia , Amido/química , Temperatura
9.
Eng Life Sci ; 19(1): 66-72, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32624957

RESUMO

This present study aims to establish a relatively cheap and effective method for preparation of ester of flavone isolated from bamboo-leaf extracts. According to this method, the solubility of bamboo leaf extract in a lipid medium could be improved, which would expand the utilization of bamboo leaf extract. Acylation of flavone with oleic acid was efficient in a system containing dried tert-amyl-alcohol and molecular sieves. The bioconversion yield ranged from 24 to 63% in different conditions. the type of fatty acids, the amount of the lipase, water content and temperature of the system were investigated in detail to influence on the performance of the acylation reaction. High purity of ester (>95%) was obtained by a two-step solvent purification procedure and chromatographic separation. Followed by the 1H and 13C nuclear magnetic resonance spectroscopy analysis, single product of 6''-O-oleate isoorientin ester was detected. Introducing an acyl group into isoorientin significantly improved its lipophilicity yet slightly reduced their antioxidant activity, while its antioxidant activity still significantly better than VE.

10.
Carbohydr Polym ; 197: 608-613, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30007653

RESUMO

Nisin is a small cationic peptide composed of 34 amino acid residues, it exhibits a wide spectrum antimicrobial activity against Gram-positive bacteria, but nisin has the disadvantages of poor stability and short duration of antibacterial activity. In order to improve the stability of nisin during food processing and storage period, the gum arabic (GA) is used to get GA-nisin microparticles. The analysis of zeta potential, SEM and FT-IR were used to characterize the combination of GA and nisin, test the antibacterial activity on Staphylococcus aureus and Escherichia coli, the bactericidal effect of GA-nisin microparticles decreased within 24 h compare to free nisin, however, GA-nisin microparticles after 121 °C treatment for 10 min, the activity loss rate is less than free nisin and has better sustained antibacterial effect at 25 °C. The results shown GA-nisin microparticles have better high-temperature stability and sustained bactericidal ability than the free nisin.

11.
J Nanosci Nanotechnol ; 18(8): 5837-5841, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29458650

RESUMO

Nano-SiO2 is an inexpensive material for enzyme immobilization and has been frequently utilized for this purpose. In addition to its low cost, Nano-SiO2 has several advantages when used as a supporting material, including its lack of toxicity and chemical reactivity, allowing easy fixation of enzymes. In this article, Porcine Pancreatic lipase was non-covalently immobilized on Nano-SiO2. The properties of immobilized enzyme were then defined. The optimum pH and temperature for the immobilized PPL for hydrolysis of olive oil were determined as 7.6 and 40-50 °C, respectively. The immobilized enzyme possessed high stability in batch operation; with 73.5% of the initial activity still remaining after 8 times of repeated operation of the immobilized lipase. The immobilized enzyme was more stable than free enzyme and t1/2 was 25 d, while free lipase activity was lost 50% in 2 days. The apparent Km for the immobilized enzyme was significantly smaller than that of the free one.


Assuntos
Enzimas Imobilizadas , Lipase/química , Nanocompostos , Dióxido de Silício , Animais , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Hidrólise , Suínos , Temperatura
12.
Nat Prod Res ; 32(15): 1817-1823, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29171302

RESUMO

One novel and eight known oxidatively rearranged cycloartane triterpenoids were isolated from the seeds of Pseudolarix amabilis. The structure of the new isolate was elucidated on extensive spectroscopic analyses. Results indicated that pseudolarolide Q (4) exhibited strong antimicrobial activity against Gram-positive Staphylococcus aureus and Candida albicans at the MICs of 6.08 and 24.32 µM, respectively. Pseudolarolide I (2) showed the 11ß-HSD1 inhibitory property at the IC50 value of 34.5 nM.


Assuntos
Pinaceae/química , Triterpenos/química , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/antagonistas & inibidores , Animais , Anti-Infecciosos/química , Candida albicans/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Camundongos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Sementes/química , Staphylococcus aureus/efeitos dos fármacos , Triterpenos/isolamento & purificação , Triterpenos/farmacologia
13.
World J Microbiol Biotechnol ; 33(6): 116, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28488199

RESUMO

Optimization of compatible solutes (ectoine) extraction and purification from Halomonas elongata cell fermentation had been investigated in the laboratory tests of a large scale commercial production project. After culturing H. elongata cells in developed medium at 28 °C for 23-30 h, we obtained an average yield and biomass of ectoine for 15.9 g/L and 92.9 (OD600), respectively. Cell lysis was performed with acid treatment at moderate high temperature (60-70 °C). The downstream processing operations were designed to be as follows: filtration, desalination, cation exchange, extraction of crude product and three times of refining. Among which the cation exchange and extraction of crude product acquired a high average recovery rate of 95 and 96%; whereas a great loss rate of 19 and 15% was observed during the filtration and desalination, respectively. Combined with the recovering of ectoine from the mother liquor of the three times refining, the average of overall yield (referring to the amount of ectoine synthesized in cells) and purity of final product obtained were 43% and over 98%, respectively. However, key factors that affected the production efficiency were not yields but the time used in the extraction of crude product, involving the crystallization step from water, which spended 24-72 h according to the production scale. Although regarding to the productivity and simplicity on laboratory scale, the method described here can not compete with other investigations, in this study we acquired higher purity of ectoine and provided downstream processes that are capable of operating on industrial scale.


Assuntos
Diamino Aminoácidos/química , Diamino Aminoácidos/isolamento & purificação , Halomonas/química , Halomonas/metabolismo , Microbiologia Industrial/métodos , Técnicas de Cultura Celular por Lotes , Biomassa , Reatores Biológicos/microbiologia , Técnicas de Química Analítica/métodos , Meios de Cultura , Fermentação , Halomonas/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Temperatura
14.
Carbohydr Polym ; 165: 96-102, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28363580

RESUMO

A new solid-phase extraction mode was developed for separation some flavones from the complex interference system. In the experiment, rhein anchored on magnetic chitosan microparticles, prepared facilely without removal of the template molecule, was used as sorbents for the extraction of target analytes; after completion of the extraction process, Fe3O4 particles acted as carrier to retrieve rhein functionalized magnetic chitosan microparticles (RMCMPs) from the sample solution. RMCMPs showed excellent selective adsorption capacity of isoflavones. The result suggested that the method was useful for fast determination and quantification of isoflavones in soymilk. The RMCMPs were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transforms infrared spectrometer (FTIR).


Assuntos
Antraquinonas/química , Quitosana/química , Isoflavonas/análise , Magnetismo , Extração em Fase Sólida , Leite de Soja/química , Adsorção , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
15.
Biotechnol Appl Biochem ; 64(2): 251-258, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26854002

RESUMO

A mycelium-bound lipase from Aspergillus oryzae (AOL) exhibited excellent enantioselectivity for kinetic resolution of (RS)-1-phenylethanol ((RS)-1-PE) in organic solvent. The various reaction parameters affecting the conversion and enantioselectivity were studied, including type of acyl donor, solvent, molar ratio, temperature, enzyme amount, and substrate concentration. The optimum reaction conditions were found to be transesterification with vinyl acetate at 30 °C in methyl tert-butyl ether with a vinyl acetate: (RS)-1-PE molar ratio of 1:1 and an enzyme concentration of 60 g/L. At the optimum reaction conditions, the conversion could reach above 46% with >99% enantiomeric excess of the product, (R)-1-phenylethyl acetate, when the substrate concentration was below 1.4 M. The enzyme displayed an excellent enantioselectivity with an E-value of >200 and a strong tolerance for high substrate concentration of up to 1.8 M. Those results indicated that AOL was a promising biocatalyst in the kinetic resolution of (RS)-1-PE.


Assuntos
Aspergillus oryzae/enzimologia , Álcoois Benzílicos/metabolismo , Lipase/química , Álcoois Benzílicos/química , Esterificação , Cinética , Lipase/genética , Micélio/enzimologia , Solventes/química , Estereoisomerismo
16.
Eng Life Sci ; 17(6): 629-634, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32624808

RESUMO

To increase the antimicrobial activities of chitosan, chitosan nanoparticles loaded with Fe2+ or Fe3+ were prepared by surfactant-assisted chitosan chelating Fe2+, Fe3+ and ionic gelation chitosan. Their chelating rates were determined by spectrophotometry. The particle sizes and zeta potentials of chitosan nanoparticles loaded with Fe2+ or Fe3+ were measured by size and zeta potential analysis. The nanoparticles antimicrobial activities were evaluated by different concentration against Escherichia coli, Staphylococcus aureus, Candida albicans in vitro. Results showed that the mean diameter of chitosan nanoparticles loaded with Fe2+ or Fe3+ were 206.4 and 195.2 nm, respectively. Their zeta potentials were +28.82 and +28.26 mV, respectively. The chelating rate of chitosan nanoparticles loaded with Fe2+ was greatly higher than with Fe3+. Their antimicrobial activity was showed greatly higher at lower concentrations compared to chitosan, and the antibacterial effect of chitosan nanoparticles loaded with Fe2+ or Fe3+ was preliminary observed.

17.
Zhongguo Zhong Yao Za Zhi ; 42(24): 4819-4826, 2017 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-29493153

RESUMO

In order to study the potential application value of lavender volatile oil (LVO), the chemical composition of the volatile oil of lavender was analyzed by GC-MS, and the mouse model of Alzheimer's disease (AD) was established. Additionally, the antioxidant enzymes activity of T-SOD, GSH-PX, CAT and MDA content were studied. Experimental results showed that 55 kinds of chemical constituents including terpene, terpene alcohol and ester compounds from LVO were identified, and the content of linalool and linalyl acetate was the highest, accounting for 49.71% of the total volatile oil. The ability of mouse platform memory was improved significantly. The levels of GSH-PX, CAT and T-SOD of mouse brain tissue in the treatment group were significantly higher than those in the model group (P<0.05). The level of MDA reached the maximum value in the model group, while there was no notable difference between the levels of MDA in the drug group and the normal group. The result indicated the significant oxidative activity of LVO, the possibility of induced oxidative stress reduction in neurons, and the reversal effect of memory acquired disorder.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Lavandula/química , Transtornos da Memória/tratamento farmacológico , Óleos Voláteis/farmacologia , Óleos Vegetais/farmacologia , Animais , Modelos Animais de Doenças , Camundongos , Estresse Oxidativo
18.
Int J Biol Macromol ; 87: 537-44, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26959172

RESUMO

Enzyme immobilized on magnetic particles can be used as efficient recoverable biocatalysts under strong magnetic response. To enable re-use of enzyme, modified Fe3O4 particles were used as carrier to immobilize α-amylase in this paper. Firstly, the surface of Fe3O4 particles were coated with amino groups by direct using TEOS (tetraethoxysilane) followed by treatment with APTES (3-aminopropyltriethoxysilane) and then carboxylated by reacting it with succinic anhydride. In addition, the effect of the immobilization condition on enzyme activity recovery and immobilization efficiency were investigated. The results showed that the optimal immobilization occurred under following conditions: pH 5.5, 40°C, enzyme concentration of 20mgmL(-1), reaction time for 36h. Using immobilized α-amylase as biocatalyst, the optimum pH and temperature for hydrolysis were observed to be 6.5 and 60°C. The kinetics of hydrolysis reaction were studied using Michaelis-Menten equation. The affinity constant (Km) and maximum reaction rate (vmax) of magnetic particles immobilization α-amylase (MPIA) was 0.543mgmL(-1) and 1.321mgmin(-1) compared to those of 0.377mgmL(-1) and 6.859mgmin(-1) of free enzyme. After immobilization, enzymatic activity, storage stability, thermo-stability, and reusability of MPIA were found superior to those of the free one. MPIA maintained 86% enzyme activity after 30 days and maintained 78% enzyme activity after recycling six times.


Assuntos
Amilose/química , Biocatálise , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Nanopartículas de Magnetita/química , alfa-Amilases/química , alfa-Amilases/metabolismo , Animais , Bovinos , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Hidrólise , Solventes/química , Temperatura
19.
J Chromatogr Sci ; 53(6): 898-902, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25362198

RESUMO

Trypsin is a serine protease that has been proposed as a potential therapeutic target for metabolic disorders and malignancy diseases, thus the identification of biomolecular interactions of compounds to trypsin could be of great therapeutic importance. In this study, trypsin was immobilized on a monolithic silica capillary column via sol-gel. The binding properties of four small molecules (daidzin, genistin, matrine and oxymatrine) to trypsin were examined using the trypsin affinity columns by frontal analysis. The results indicate that the matrine (dissociation constant, Kd = 7.904 µM) has stronger interaction with trypsin than the oxymatrine (Kd = 8.204 µM), whereas daidzin and genistin were nearly have no affinity with trypsin. The results demonstrated that the frontal affinity chromatography can be used for the direct determination of protein-protease inhibitor binding interactions and have several significant advantages, including easy fabricating, reproducible, minimal technological requirements and potential to become a reliable alternative for quantitative studies of biomolecular interactions.


Assuntos
Cromatografia de Afinidade/métodos , Enzimas Imobilizadas/metabolismo , Inibidores da Tripsina/análise , Inibidores da Tripsina/metabolismo , Tripsina/metabolismo , Alcaloides , Enzimas Imobilizadas/química , Isoflavonas , Cinética , Modelos Químicos , Quinolizinas , Dióxido de Silício , Tripsina/química , Inibidores da Tripsina/química
20.
J Food Sci Technol ; 51(7): 1318-25, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24966425

RESUMO

Lycopene belongs to the carotenoid family with high degree of unsaturation and all-trans form. Lycopene is easy to isomerize and auto oxide by heat, light, oxygen and different food matrices. With an increasing understanding of the health benefit of lycopene, to enhance stability and bioavailability of lycopene, ultrasonic emulsification was used to prepare lycopene microcapsules in this article. The results optimized by response surface methodology (RSM) for microcapsules consisted of four major steps: (1) 0.54 g glycerin monostearate was fully dissolved in 5 mL ethyl acetate and then added 0.02 g lycopene to form an organic phase, 100.7 mL distilled water which dissolved 0.61 g synperonic pe(R)/F68 as the aqueous phase; (2) the organic phase was pulled into the aqueous phase under stirring at 60 °C water bath for 5 min; (3) the mixture was then ultrasonic homogenized at 380 W for 20 min to form a homogenous emulsion; (4) the resulting emulsion was rotary evaporated at 50 °C water bath for 10 min under a pressure of 20 MPa. Encapsulation efficiency (EE) of lycopene microcapsules under the optimized conditions approached to 64.4%.

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