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Liu J.-F.,Tianjin University of Commerce | Liu J.-F.,Tianjin Key Laboratory of Food Biotechnology | Liu H.,Chinese Academy of Agricultural Sciences | Tan B.,Academy of State Administration of Grain | And 2 more authors.
Journal of Molecular Catalysis B: Enzymatic | Year: 2012

A nanosized support for reversible immobilization of enzymes, magnetic poly(glycidyl methacrylate-ethylene glycol dimethacrylate-hydroxyethyl methacrylate) nanospheres grafted with polyethyleneimine, was prepared and characterized by scanning electron microscopy and vibrating sample magnetometry. The novel support displayed 3.2-fold higher adsorption capacity for Kluyveromyces fragilis β-galactosidase than commercial ion exchange resin DEAE-Sepharose, the maximum amount of the enzyme adsorbed on the support reached 86.7 mg/g with enzyme activity recovery of 92.5%. The adsorbed K. fragilis β-galactosidase showed high catalytic activity and operational stability for synthesis of galacto-oligosaccharide (GOS), 4.5 kg of GOS were produced per gram of adsorbed enzyme from lactose during 15 consecutive batch reactions by reuse of the same biocatalyst, and the immobilized biocatalyst retained about 84.6% of its initial activity after 15 cycles of batch operation. The support could be regenerated and reused, remaining 93.0% of its original adsorption capacity at the end of the twentieth adsorption-desorption cycle. © 2012 Elsevier B.V. Source


Zhang Y.,Tianjin University of Commerce | Zhang Y.,Tianjin Key Laboratory of Food Biotechnology | Ma G.,Tianjin University of Commerce | Xie J.,Tianjin University of Commerce | Xie J.,Tianjin Key Laboratory of Food Biotechnology
Journal of Liquid Chromatography and Related Technologies | Year: 2015

Jujuboside A (JuA), a dammarane-type triterpene glycoside, is a main bioactive saponin in Zizyphi Spinosi Semen (a traditional Chinese herbal food). In this research, the distribution of JuA in Sprague-Dawley rats was investigated with a new and efficient HPLC-ESI-MS/MS method. The results showed that JuA distributed rapidly and widely in various rat tissues (including heart, liver, spleen, kidney, and lung) after intravenous administration. In addition, it was initially found that JuA could pass through the blood-brain barrier and reach various areas of the brain quickly. At 0.25 hr, the concentration of JuA in the hippocampus (204.10 ng·g-1) was significantly higher than in the cerebrum (144.27 ng·g-1), olfactory bulb (98.42 ng·g-1), and corpus striatum (76.04 ng·g-1) (p < 0.05), indicating that the hippocampus was the main accumulation area of JuA in the brain. © 2015 Taylor & Francis Group, LLC. Source


Li Y.,Tianjin University of Commerce | Zhang Y.,Tianjin University of Commerce | Zhang Y.,Tianjin Key Laboratory of Food Biotechnology | Yang T.,Hebei University of Technology | And 5 more authors.
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2015

A sensitive and credible high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established and validated for the determination of isovitexin in rat plasma and various tissues (including heart, liver, lung, kidney, stomach, intestine, muscle, brain and cerebellum). The samples were prepared with methanol by liquid-liquid extraction, and puerarin was used as the internal standard. The chromatographic separation was carried out on an Agilent Poroshell 120 EC-C18 column (4.6mm×50mm, 2.7μm) with a mobile phase consisting of acetonitrile and 0.1% formic acid (21:79, v/v). The MS analysis was performed by multiple reaction monitoring (MRM) with electronic spray ionization source (ESI-) for quantitative response of isovitexin (431.0→311.0) and puerarin (415.1→295.0). The linearity of isovitexin in all the biosamples was good, with correlation coefficients greater than 0.9912 within the corresponding concentration range. The intra- and inter-day precisions in plasma and various tissues were less than 11.80%, and the accuracy (RE %) ranged from -4.89% to 4.78%. The extraction recoveries were in the range of 72.70%-90.81%. The present method was successfully applied to pharmacokinetics and tissue distribution of isovitexin in rats after tail vein injection with 2.0mg/kg of the compound. The pharmacokinetic parameters were demonstrated as followed: the half-life (t1/2) was 1.05±0.325h, the apparent volume of mean residual time (MRT) was 1.229±0.429h, and the area under the curve (AUC) was 11.39±5.05μg/mL/h. The results of tissue distribution showed that the main tissue depots for isovitexin in rats were kidney, intestine and liver. The results provided a meaningful insight for the further pharmacological investigation of isovitexin. © 2015 Elsevier B.V. Source


Xie J.,Tianjin University of Commerce | Xie J.,Tianjin Key Laboratory of Food Biotechnology | Zhang Y.,Tianjin University of Commerce | Zhang Y.,Tianjin Key Laboratory of Food Biotechnology | And 2 more authors.
Journal of Food Composition and Analysis | Year: 2011

A new and rapid method was developed for simultaneous identification and determination of 11 polyphenols in Herba lycopi, i.e. rosmarinic acid, protocatechuic aldehyde, protocatechuic acid, caffeic acid, ferulic acid, apigenin, luteolin, quercetin, isorhamnetin, chlorogenic acid and rutin, using high performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry (MS/MS). Quantitation was based on multiple reactions monitoring (MRM) using the precursor→production combination for the determination of 11 analytes. The analysis was performed on an Eclipse Plus C18 column (I.D. 4.6mm×100mm, 3.5μm particle size). An electrospray ionization (ESI)-tandem interface in the negative mode was employed prior to mass spectrometric detection. With the optimized conditions, the 11 biomarkers were detected properly within 3min. Limits of detection (LOD) ranged from 0.6 to 2.6ng/ml. The average recoveries ranged from 95.42 to 101.11% with RSDs≤2.23%. The applicability of this analytical approach was confirmed by the successful analysis of 3 samples. The established method was validated and found to be sensitive and reliable for the determination of 11 analytes in Herba lycopi. © 2011 Elsevier Inc. Source


Qiao L.,Tianjin University of Commerce | Jiao L.,Tianjin University of Commerce | Pang G.,Tianjin University of Commerce | Pang G.,Tianjin Key Laboratory of Food Biotechnology | And 2 more authors.
Biosensors and Bioelectronics | Year: 2015

A novel taste biosensor based on ligand-receptor interaction was developed through fixing taste-bud tissues of SD rats to a glassy carbon electrode. Using the sodium alginate-starch gel as a fixing agent, taste-bud tissues of SD rats were fixed between two nuclear microporous membranes to make a sandwich-type sensing membrane. With the taste biosensor, the response current induced by capsaicin and gingerol stimulating the corresponding receptors was measured. The results showed that the lowest limit of detection of this biosensor to capsaicin was 1×10-13mol/L and the change rate of response current was the highest at the concentration of 9×10-13mol/L, indicating that the capsaicin receptor was saturated at this point. The lowest limit of detection of this biosensor to gingerol was 1×10-12mol/L, and the gingerol receptor was saturated when the concentration of gingerol was 3×10-11mol/L. It was demonstrated that the interaction curves of capsaicin and gingerol with their respective receptors exhibited high correlation (R2: 0.9841 and 0.9904). The binding constant and dissociation constant of gingerol with its receptor were 1.564×10-11 and 1.815×10-11 respectively, which were all higher than those of capsaicin with its receptor (1.249×10-12 and 2.078×10-12). This study, for the first time, made it possible to quantitatively determine the interaction of the taste receptor and pungent substances with a new biosensor, thus providing a simple approach for monitoring pungent substances and investigating the mechanism of ligand-receptor interaction. © 2015 Elsevier B.V.. Source

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