酸催化水解阿拉伯胶制备L-阿拉伯糖工艺

阿拉伯胶是提取制备L-阿拉伯糖的理想原料,对阿拉伯胶进行酸催化水解可获得含L-阿拉伯糖、D-半乳糖、L-鼠李糖的反应液,优化酸水解条件使水解液中L-阿拉伯糖的含量和收率均达到最佳水平,是保证后续分离纯化工艺稳定性及产品品质的关键。利用单因素实验考察了反应时间、酸浓度、反应温度、固液比等因素对水解工艺的影响,获得了影响酸水解反应的关键因素及适宜的水解条件。结果表明:温度对L-阿拉伯糖的生成速率有明显影响。经优化,当固液比为1:10 (g/ml)、100℃、0.1 mol·L^-1 H₂SO₄水解90 min或90℃、0.1 mol·L^-1 H₂SO₄水解200 min,水解液中L-阿拉伯糖的相对纯度分别达85%和87%,水解收率高达85%。     

从L-阿拉伯胶提取L-阿拉伯糖

阿拉伯胶在硫酸作用下水解得到含L 阿拉伯糖的混合液,经w(C2H5OH)=90%的乙醇萃取,再经工业乙酸沉淀,可得粗L 阿拉伯糖。正交实验确定了酸性水解反应的影响因素和最佳条件为:水解温度90～100℃,w(H2SO4)=1 0%,L 阿拉伯糖的粗收率为85%,质量分数为66 7%。经双柱色谱分离提纯L 阿拉伯糖,所用洗脱剂分别为:V(正丁醇)∶V(乙酸乙酯)∶V(异丙醇)∶V(乙酸)∶V(水)=3 5∶10∶6 5∶3∶3和V(乙酸乙酯)∶V(异丙醇)∶V(水)=5∶2 2∶1 1,得到收率大于50%,质量分数为99%的L 阿拉伯糖。     

L-阿拉伯糖研究进展

综述了L-阿拉伯糖的最新研究进展.内容包括:L-阿拉伯糖的提取及用途、L-阿拉伯糖的传统提取工艺和设备的改进以及L-阿拉伯糖的合成.     

L-阿拉伯糖研究进展

L-阿拉伯糖是一种新兴的低热量功能性糖,在自然界中,广泛存在于玉米皮、甜菜根、阿拉伯胶等中。L-阿拉伯糖在血糖、血脂的调节方面有广阔的前景。本文综述了L-阿拉伯糖的制备方法,并介绍了L-阿拉伯糖的性质,展望了L-阿拉伯糖生产的发展趋势。     

阿拉伯糖催化制取L-核糖的工艺研究

本文对L-阿拉伯糖差相异构反应生成L-核糖进行了实验研究;通过正交试验分析确定了最佳阿拉伯糖转化条件:PH值2.5、反应温度95℃、钼酸铵加入量0.5%、糖液浓度15%,L-阿拉伯糖的转化率达16.9%。     

由骨胶水解液中分离提取L-羟脯氨酸和L-脯氨酸的实验研究

本文报道了由骨胶水解液中分离提取 L -羟脯氨酸和 L-脯氨酸的工艺。产品产率为 L-Hy P5.2 8% ;L-Pro3 .6 %。工业化产品经按日本有关标准检测全部合格。该工艺已通过内蒙古自治区经委的验收     

L-缬氨酸结晶工艺研究进展

简述了L-缬氨酸的发展现状、生产工艺、含量测定方法,分析了工业结晶过程中工艺条件对L-缬氨酸产品质量的影响,展望了国产L-缬氨酸工业提升产品质量的发展方向,指出深入开展L-缬氨酸工业结晶过程研究,开发具有自主知识产权的国产L-缬氨酸新工艺,对于提升国产L-缬氨酸产品质量和增加国内生产企业的国际竞争力具有重要意义。     

阿拉伯糖和其他糖类复聚衍生物发展动向

阿拉伯糖和其他糖类结合的复聚衍生物广泛存在于自然界,且对人体健康有重要的生理功能。但自然界并无游离的阿拉伯糖存在,需由人工从阿拉伯糖的复聚衍生物中提取。国内自2008年卫生部批准L阿拉伯糖单糖为新资源食品以来,对阿拉伯糖的功能有较多的报导,但对于阿拉伯糖和其他糖类复聚衍生物的报导较少。为使读者能更多地了解阿拉伯糖、阿拉伯糖和其他糖类复聚衍生物的发展动向,本文对其进行简要介绍。     

NaCl盐析法从猪血粉水解液中提取L-亮氨酸

以NaCl为盐析剂从猪血粉水解液中盐析沉淀L-亮氨酸,确定了盐析沉淀所需的时间,考察了温度、pH值、NaCl加入量等因素对L-亮氨酸盐析沉淀率的影响。结果表明:盐析剂NaCl在原料液全溶解后搅拌半小时盐析沉淀率基本上达到最大值;低温对于盐析沉淀是有利的,工业生产中可在室温下或低温下进行;在溶液的pH值约为2时,NaCl存在下L-亮氨酸以二亮氨酸盐酸盐形式析出,沉淀率达到最大;溶液中氯化钠浓度越高盐析沉淀率越高,工业生产上可按0.35g/mL的比例加入NaCl。室温下控制猪血粉水解液的pH值为2,按0.35g/mL原料液的比例加入NaCl盐析出二亮氨酸盐酸盐,经精制得L-亮氨酸产品,产品符合《中华人民共和国药典》(2000年版二部)质量标准,L-亮氨酸的平均提取率为82.36%。     

Complex Coacervation of O-Carboxymethylated Chitosan and Gum Arabic

The effects of O-carboxymethylation modification on the coacervation of chitosan with gum arabic (GA) were investigated. O-carboxymethylated chitosan (O-CMC) carried less net positive charge in acidic solutions and its optimum pH and biopolymer ratio for coacervation with GA were lower than those of native chitosan. O-carboxymethylation modification decreased the optimum coacervation temperature from 45 to 25°C and greatly increased the sensitivity to ionic strength. Meanwhile, insoluble O-CMC–GA coacervates were formed in relative lower critical total biopolymer concentration than chitosan–GA coacervates. It was concluded that the O-carboxymethylation modification markedly influenced the electrostatic interaction of chitosan with GA.     

Broad Spectrum Anti-Bacterial Activity and Non-Selective Toxicity of Gum Arabic Silver Nanoparticles

Silver nanoparticles (AgNPs) are the most commercialized nanomaterials and presumed to be biocompatible based on the biological effects of the bulk material. However, their physico-chemical properties differ significantly to the bulk materials and are associated with unique biological properties. The study investigated the antimicrobial and cytotoxicity effects of AgNPs synthesized using gum arabic (GA), sodium borohydride (NaBH₄), and their combination as reducing agents. The AgNPs were characterized using ultraviolet-visible spectrophotometry (UV-Vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). The anti-bacterial activity was assessed using agar well diffusion and microdilution assays, and the cytotoxicity effects on Caco-2, HT-29 and KMST-6 cells using MTT assay. The GA-synthesized AgNPs (GA-AgNPs) demonstrated higher bactericidal activity against all bacteria, and non-selective cytotoxicity towards normal and cancer cells. AgNPs reduced by NaBH₄ (C-AgNPs) and the combination of GA and NaBH₄ (GAC-AgNPs) had insignificant anti-bacterial activity and cytotoxicity at ≥50 µg/mL. The study showed that despite the notion that AgNPs are safe and biocompatible, their toxicity cannot be overruled and that their toxicity can be channeled by using biocompatible polymers, thereby providing a therapeutic window at concentrations that are least harmful to mammalian cells but toxic to bacteria.     

微波辐射制备阿拉伯胶接枝2-丙烯酰胺基-2-甲基丙磺酸高吸水树脂及溶胀性能

以阿拉伯胶(GA),2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为原料,N,N-亚甲基双丙烯酰胺(NMBA)为交联剂,过硫酸钾(APS）为引发剂,采用微波辐射方法制备了GA-g-PAMPS 高吸水性树脂。探讨了单体配比、交联剂用量、引发剂用量、中和度、微波功率和辐射时间对吸水倍率的影响,研究了树脂的溶胀性能,并用FTIR对吸水性树脂的结构进行了表征。结果表明：最佳合成条件下树脂吸去离子水倍率为683g/g,吸生理盐水倍率为137g/g。树脂的吸水倍率随着无机盐溶液浓度的增加而减小,在不同价态金属离子盐溶液中,树脂的吸水倍率顺序为NaCl>BaCl2> FeCl3,树脂具有较高的吸水速率和较好的重复吸水性能。     

微波辐射制备阿拉伯胶接枝2-丙烯酰胺基-2-甲基丙磺酸高吸水树脂及溶胀性能

以阿拉伯胶(GA),2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为原料,N,N-亚甲基双丙烯酰胺(NMBA)为交联剂,过硫酸钾(APS）为引发剂,采用微波辐射方法制备了GA-g-PAMPS 高吸水性树脂。探讨了单体配比、交联剂用量、引发剂用量、中和度、微波功率和辐射时间对吸水倍率的影响,研究了树脂的溶胀性能,并用FTIR对吸水性树脂的结构进行了表征。结果表明：最佳合成条件下树脂吸去离子水倍率为683g/g,吸生理盐水倍率为137g/g。树脂的吸水倍率随着无机盐溶液浓度的增加而减小,在不同价态金属离子盐溶液中,树脂的吸水倍率顺序为NaCl>BaCl2> FeCl3,树脂具有较高的吸水速率和较好的重复吸水性能。     

微波辐射阿拉伯胶接枝2-丙烯酰胺基-2-甲基丙磺酸制备高吸水树脂及溶胀性能

以阿拉伯胶(GA)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为原料,N,N-亚甲基双丙烯酰胺(NMBA)为交联剂,过硫酸钾(APS)为引发剂,采用微波辐射方法制备了GA-g-PAMPS高吸水性树脂。探讨了单体配比、交联剂用量、引发剂用量、中和度、微波功率和辐射时间对吸水倍率的影响,研究了树脂的溶胀性能,并用FTIR对吸水性树脂的结构进行了表征。结果表明:最佳合成条件下得到的树脂吸去离子水倍率为683 g/g,吸生理盐水倍率为137 g/g。树脂的吸水倍率随着无机盐溶液浓度的增加而减小,在不同价态金属离子盐溶液中,树脂的吸水倍率从大到小的顺序为Na ClBa Cl2Fe Cl3,树脂具有较高的吸水速率和较好的重复吸水性能。     

阿拉伯树胶增敏-新试剂对碘偶氮氯膦与铋离子显色反应的研究与应用

在pH =2 0的HCl-HAc介质中 ,对碘偶氮氯膦与Bi3 + 生成蓝紫色的配合物 ,其最大吸收波长的位置在 6 84nm ,摩尔吸光系数为 1 15× 10 4,Bi3 + 浓度在 0～ 5mg/L范围内符合比尔定律。表面活性剂具有增敏作用 ,在测定条件下 ,加入 0 5 %的阿拉伯树胶 2mL ,其线形回归方程为c =- 1 0 74 +3 5 5 7A(mg/L)。     

Thermodynamic and Quality Properties of Lemon Juice Powder as Affected by Maltodextrin and Arabic Gum

Sorption isotherms of lemon juice (LE) powders with and without additives—18% maltodextrin (MA) or 18% gum Arabic (GA)—were determined at 20-50°C. Addition of additives was shown to affect the isotherms in such a way that, at the same water activity, samples LE + GA and LE + MA presented lower equilibrium moisture content and were not so affected by varying temperature. The net isosteric heats of sorption of juice powders with additives were higher (less negative) than those of lemon juice powders, suggesting that there are more active polar sites in the product without addition of GA or MA. In general, the quality properties decreased with the addition of maltodextrin and gum arabic and it was obtained similar values for LE + GA and LE + MA.     

Thermodynamic and Quality Properties of Lemon Juice Powder as Affected by Maltodextrin and Arabic Gum

Sorption isotherms of lemon juice (LE) powders with and without additives—18% maltodextrin (MA) or 18% gum Arabic (GA)—were determined at 20–50°C. Addition of additives was shown to affect the isotherms in such a way that, at the same water activity, samples LE + GA and LE + MA presented lower equilibrium moisture content and were not so affected by varying temperature. The net isosteric heats of sorption of juice powders with additives were higher (less negative) than those of lemon juice powders, suggesting that there are more active polar sites in the product without addition of GA or MA. In general, the quality properties decreased with the addition of maltodextrin and gum arabic and it was obtained similar values for LE + GA and LE + MA.     

L-谷氨酰胺的制备及分离方法研究

L-谷氨酰胺被认为是目前所知道的最重要的氨基酸之一,是一种极有前途的新药、保健品。介绍了L-谷氨酰胺的制备方法以及分离提取方法的研究进展。