环糊精包合物在食品工业中的应用

介绍了各种环糊精的理化性质及其包合物的制备方法,并且对环糊精在防止食品成分由于光、热和氧气引起的变性,消除食品中苦味和不愉快的气味,螯合食品中的胆固醇和对食品进行保藏作用等方面的应用进行了阐述,表明环糊精在食品工业上具有广阔的发展前景。     

Synthesis and Characterization of Nano‐Encapsulated Black Pepper Oleoresin using Hydroxypropyl Beta‐Cyclodextrin for Antioxidant and Antimicrobial Applications

Previous studies have reported antimicrobial and antioxidant activity of black pepper oleoresin which is associated to its phenolic compounds and piperine. The ability of cyclodextrins to form an inclusion complex with a guest molecule could improve black pepper oleoresin application, bioavailability, and stability in foods. Hydroxypropyl beta‐cyclodextrin (HPBCD) inclusion complex with black pepper olereosin were synthesized using the kneading method and characterized for its physico‐chemical properties and its antioxidant and antimicrobial activities. Inclusion complex size was 103.9 ± 7.6 nm and indicated to be a polydisperse system. The entrapment efficiency was 78.3 ± 3.6%, which suggests that other constituents in black pepper oleoresin have higher affinities for HPBCD than piperine (major compound in black pepper oleoresin). Thermograms showed the disappearance of oxidation peaks of black pepper oleoresin, proving complex formation with HPBCD. Phase solubility results indicated 1:1 stoichiometric inclusion complex formation and an increase of black pepper oleoresin aqueous solubility with HPBCD concentration. Nano‐encapsulation with HPBCD did not affect (P > 0.05) total phenolic content; however, it enhanced (P < 0.05) black pepper oleoresin antioxidant activity. Black pepper oleoresin and its inclusion complex were analyzed for their antimicrobial activity against Escherichia coli K12 and Salmonella enterica serovar Typhimurium LT2. Both free and encapsulated black pepper oleoresin effectively inhibited bacterial growth within the concentration range tested. Black pepper oleoresin encapsulated in HPBCD was able to inhibit Salmonella at lower (P < 0.05) concentrations than its corresponding free extract. Therefore, black pepper oleoresin‐HPBCD nanocapsules could have important applications in the food industry as antimicrobial and antioxidant system.     

分子包埋法制备姜油树脂微胶囊的研究

以姜为原料，经乙醇直接浸泡和索氏提取法获得的姜油树脂为心材，以β-环糊精和阿拉伯胶为壁材，经乳化、均质、喷雾干燥，制取姜油树脂微胶囊，并对其主要技术参数进行了测定。通过正交试验分析，以姜油树脂的包埋率为指标，确定了心壁材比、包接温度、搅拌时间、阿拉伯胶和β-环糊精比四个因素的最佳值，得出了姜油树脂微胶囊化的最佳工艺条件。     

可吸收苯纺织品的制备

采用溶胶-凝胶法将羟丙基β-环糊精整理到涤纶织物上,制备了可吸收空气中苯的功能纺织品。该整理后,织物纤维表面和部分相邻纤维间覆盖了一层薄膜。用气相色谱仪测定一段时间内织物中的苯含量,发现整理织物比原织物多吸收55.5%的苯,且480 h(20 d)后,织物内仍残留一定量的苯。     

Strategic Engineering of Sub-5 nm Dyes@CDs Nanoassemblies Platform for Super Resolution Imaging

The design and construction of fluorescence probes with small size, high quantum yield, photostability, and solubility in an aqueous solution to achieve biomarker have become a focus of interest in super-resolution bioimaging application. Herein, four kinds of GFP-like supramolecular nanoassemblies (SNAs) are constructed in a very facile manner by the host–guest interaction between isopercolic acid derivatives (IADs) and cyclodextrin (CD). ¹H NMR, Fourier transform infrared spectroscopy (FT-IR) and single crystal structure well prove the formation of SNAs. Moreover, compared to the initial state, the fluorescence quantum yield of the SNAs is dramatically improved through suppressing nonradiative relaxation pathways and shielding quenchers. The bimolecular exciton–exciton annihilation (bmEA) process under the high pumping fluence has been suppressed effectively. Both the improved gain and the reduced loss facilitate the buildup of stimulated emission and enable the high stimulated emission efficiency of these SNAs. Sub-5 nm IADs@β-CDs-mediated STED imaging exhibits excellent stimulated emission depletion (STED) performance: high photostability, low saturation intensity ( ≈ 0.50 MW cm⁻²), and high resolution (30 nm) under P_STED-775 nm of 109 MW cm⁻². This supramolecular strategy avoids the tedious molecular synthesis process and paves a new pathway for insights into building up novel high-performance STED probes.     

Preparation and Characterization of Zwitterionic Poly(β‐cyclodextrin‐co‐guanidinocitrate) Hydrogels for Ciprofloxacin Controlled Release

A facile, safe, and environmentally friendly approach to the preparation of poly(β‐cyclodextrin‐co‐guanidinocitrate) (ZWβCDP) via polymerization of β‐cyclodextrin (β‐CD) in the presence of guanidinocitrate as a novel cross‐linker is reported. Novel zwitterionic guanidinocitrate cross‐linker is synthesized by in situ reaction of melted guanidine and citric acid during polymerization. The structure of achieved hydrogels is characterized by attenuated total reflection‐Fourier‐transform infrared (ATR‐FTIR), X‐ray photoelectron spectroscopy, thermogravimetric analysis, differential thermogravimetric, differential scanning calorimetry (DSC), differential of DSC, and X‐ray diffraction analyses and also by Kjeldahl and colorimetric methods for elemental analyses. The swelling ratio of the anionic β‐CD polymer (ANβCDP) and ZWβCDPs is determined in water and simulated physiological media. Subsequently, the hydrogels/ciprofloxacin (CFX, as a model antibiotic drug) complexes are prepared to improve the thermal stability of CFX and define potential pharmaceutical applications of hydrogels. Solid‐state characterization of hydrogels/CFX complexes is investigated by ATR‐FTIR and DSC. The in vitro release behavior of CFX from hydrogels is investigated at simulated physiological media, which exhibit initial burst and then slow drug release. The CFX release from ZWβCDP is slower than ANβCDP.

     

Grafting of cyclodextrins onto polypropylene nonwoven fabrics for the manufacture of reactive filters. II. Characterization

A novel method for the preparation of immobilized α, β, or γ‐cyclodextrins on polypropylene nonwoven supports has been previously presented. The obtained new materials were prepared by graft‐polymerization of glycidyl methacrylate onto polypropylene after activation of the support by the electron beam technique, followed by the coupling of cyclodextrins with the epoxide groups. The structure of the resulting materials is characterized in detail using Fourier transform infrared spectroscopy, solid state nuclear magnetic resonance analysis, differential scanning calorimetry, thermogravimetric analysis, and optical microscopy. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2166–2173, 2000     

The Effect of Oxidative Stress and Memantine-Incorporated Reactive Oxygen Species-Sensitive Nanoparticles on the Expression of N-Methyl-d-aspartate Receptor Subunit 1 in Brain Cancer Cells for Alzheimer’s Disease Application

The aim of this study is to fabricate reactive oxygen species (ROS)-sensitive nanoparticles composed of succinyl β-cyclodextrin (bCDsu), memantine and thioketal linkages for application in Alzheimer’s disease, and to investigate the suppression of N-methyl-d-aspartate (NMDA) receptor 1 (NMDAR1) in cells. Thioketal diamine was attached to the carboxyl group of bCDsu to produce thioketal-decorated bCDsu conjugates (bCDsu-thioketal conjugates) and memantine was conjugated with thioketal dicarboxylic acid (memantine-thioketal carboxylic acid conjugates). Memantine-thioketal carboxylic acid conjugates were attached to bCDsu-thioketal conjugates to produce bCDsu-thioketal-memantine (bCDsuMema) conjugates. SH-SY5Y neuroblastoma cells and U87MG cells were used for NMDAR1 protein expression and cellular oxidative stress. Nanoparticles of bCDsuMema conjugates were prepared by means of a dialysis procedure. Nanoparticles of bCDsuMema conjugates had small particle sizes less than 100 nm and their morphology was found to be spherical in transmission electron microscopy observations (TEM). Nanoparticles of bCDsuMema conjugates responded to H₂O₂ and disintegrated or swelled in aqueous solution. Then, the nanoparticles rapidly released memantine according to the concentration of H₂O₂. In an in vivo animal imaging study, thioketal-decorated nanoparticles labelled with fluorescent dye such as chlorin e6 (Ce6) showed that the fluorescence intensity was stronger in the brain than in other organs, indicating that bCDsuMema nanoparticles can efficiently target the brain. When cells were exposed to H₂O₂, the viability of cells was time-dependently decreased. Memantine or bCDsuMema nanoparticles did not practically affect the viability of the cells. Furthermore, a western blot assay showed that the oxidative stress produced in cells using H₂O₂ increased the expression of NMDAR1 protein in both SH-SY5Y and U87MG cells. Memantine or bCDsuMema nanoparticles efficiently suppressed the NMDAR1 protein, which is deeply associated with Alzheimer’s disease. Fluorescence microscopy also showed that H₂O₂ treatment induced green fluorescence intensity, which represents intracellular ROS levels. Furthermore, H₂O₂ treatment increased the red fluorescence intensity, which represents the NMDAR1 protein, i.e., oxidative stress increases the expression of NMDAR1 protein level in both SH-SY5Y and U87MG cells. When memantine or bCDsuMema nanoparticles were treated in cells, the oxidative stress-mediated expression of NMDAR1 protein in cells was significantly decreased, indicating that bCDsuMema nanoparticles have the capacity to suppress NMDAR1 expression in brain cells, which has relevance in terms of applications in Alzheimer’s disease.     

Platinum-group metal cyclodextrin complexes and their use as command-cure catalysts in silicones

The Command-Cure concept is defined for a curable formulation as one with long work-like at ambient temperature and rapid cure time at elevated temperature. This concept is explored for a curable silicone system, cured via hydrosilylation. CODMCl₂ complexes (COD=1.5-cyclo-octadiene:M=Pt. Pd) are reacted with beta-cyclodextrin (-CD) to make 11 inclusion compounds,M=Pd.2;M=Pt.4. Compounds2 and4 were analyzed by¹H NMR and X-ray powder diffraction. Their catalytic ability was evaluated in a model system as well as a polymeric system that gels upon cure. Surprisingly, the Pd analog2 was a good command-cure catalyst whereas the guest compound CODPdCl₂,1, was not active in the hydrosilylation reaction. The Pt analog,4, was an effective command-cure catalyst while the corresponding guest. CODPtCl₂,3, was too active at low temperature in the hydrosilylation reaction. Additional Pt compounds and one Rh inclusion compound were evaluated as command cure catalysts. These inclusion compounds were: 11 -CD:[CODRhCl]₂,5: 11 -CD:CpPtMe₃,6 (Cp=cyclopentadienyl): 12 -CD:MeCpPtMe₃,7; 12 -CO:CODPtMe₂,8. The effectiveness of4 8 was evaluated in a number of silicone systems.