纳米糊精微球对头孢曲松钠的吸附及其释药性能

以糊精为原料,三偏磷酸钠为交联剂,利用反相微乳液法制备糊精纳米微球,并对头孢曲松钠的吸附载药和释药性能进行了研究。为模拟人体血液环境,选取了pH 7.4的磷酸二氢钠-磷酸氢二钠缓冲液为介质考查了糊精微球的吸附载药及降解性能。实验表明,纳米糊精微球对头孢曲松钠的载药率为9.44%,载药能力随着投药量的增加而增加,温度对载药能力的影响不显著,在α-淀粉酶存在的条件下,降解6 h后有23.94%的纳米糊精微球被降解。     

Investigation into the flotation response of refractory molybdenum ore to depressant mixtures:A case study

In this paper, bulk flotation followed by separation was investigated to concentrate purified molybdenite product from Jinduicheng molybdenum ores(Shanxi province, China). The bench scale tests mainly focussed on separation of molybdenite from other sulfide minerals using the new type of depressants.The effect of each single depressant, including organic depressant-modified dextrin(MD), P-Nokes reagent(PN) and sodium trithiocarbonate(ST), and their mixtures on galena, chalcopyrite and other sulfide ores, was examined in turn by changing the concentrations used in cleaner flotation tests. Closed circuit experiments were carried out under the optimal condition and satisfying recovery and grade of molybdenite concentrate could be achieved(86.294% and 53.157%, respectively). A potential reagent regime was developed, with more environmental friendly and more economical advantages due to the introduction of modified dextrin.     

GENE TECHNOLOGY FOR INDUSTRIAL YEASTS

Yeast genetics is now available as a practical tool for the development of brewing industry practices. The contribution of Brewing Research Foundation work (1978–84) to recent advances is illustrated by the construction of brewing strains with superattenuating (amylolytic) or anti-contaminant properties. Approaches based on hybridisation (by rare mating) or recombinant DNA technology have been evaluated. Techniques developed for (i) gene transfer to brewing strains, (ii) ensuring stable inheritance of novel characteristics and (iii) exploiting the secretory ability of yeast strains, can be widely applied not only with brewing, distilling, baking or wine yeasts, but also in the use of yeasts to produce novel biotechnical products. ‘Spin-off’ from these studies includes valuable methods for differentiating or enumerating wild yeasts in brewery quality control.     

Enzymatic production of linear long-chain dextrin from sago (Metroxylon sagu) starch

Pullulanase (EC.3.2.1.41) was used to generate more linear-chain dextrin from sago starch (24.9% amylose) such that the resulting product could act as a high amylose starch. A starch suspension of 5.0% (w/v) sago starch was heated at 100 °C for 45 min and, after cooling, the gelatinized sago starch was hydrolyzed with 2.0% (v/dry weight starch) pullulanase (Promozyme 400L, Novozymes A/S, Denmark) for 24 h. The linear long-chain dextrin (LLD) content of the hydrolysate after drying, was then compared with the initial LLD content. The surface morphology of the starch granules was observed with a scanning electron microscope (SEM). The effects of gelatinization, time of reaction, pretreatment with different strengths of hydrochloric acid prior to enzyme hydrolysis, and starch and enzyme concentrations were studied. Raw sago starch was resistant to the action of pullulanase, but caused an increase in the LLD of that sago starch from an initial concentration of 24.9–33.2% following gelatinization. The best conditions to maximize the amount of LLD were 5.0% (w/v) sago starch, 2.0% (v/w) enzyme and 12 h reaction time. Acid pretreatment of the sago starch did not cause greater improvement in the accessibility and susceptibility of pullulanase as the LLD content, following pullulanase action did not change significantly. Shrinkage on the surface of the starch granules was observed with the SEM.     

黄酒中非糖固形物的研究

非糖固形物是黄酒国家标准中的控制指标,也是黄酒生产企业普遍关注的一个问题。文中通过对不同生产工艺酒样糖类物质指标的理化测定及HPLC糖谱分析得到,糊精是非糖固形物中的一个重要组成部分。采用不同工艺生产的黄酒,其中糊精的含量不同,这就影响到黄酒中非糖固形物含量具有明显差异。     

淀粉类多糖在方解石和萤石表面吸附特性及作用机理

通过吸附试验，Ｘ－射线光电子能谱（ＸＰＳ）和俄歇电子能谱（ＡＥＳ）、浮选试验、系统地研究了糊精在萤石和方解石表面作用行为，结果发现，方解石经糊精作用前后ＣａＬＭＭ俄歇参数变化值为０．８０ｅＶ，变化显著，这说明糊精与方解石表面作用为化学键合；而萤石经糊精处理前后ＣａＬＭＭ俄歇参数变化值为－０．２０ｅＶ，变化不明显，说明糊精与萤石表面化学作用很弱，更接近物理作用－氢键作用；浮选试验结果证实了测试结果可     

醇酸降解淀粉制备糊精的研究

采用醇酸水解大米淀粉、高直链玉米淀粉和木薯淀粉,发现：在相同条件下,正丁醇-盐酸水解的木薯淀粉溶解性最大,且在水解3 d后无显著增加。因此,从颗粒结构、晶体结构和分子结构等方面系统地研究醇酸降解木薯淀粉制备糊精过程。经正丁醇-盐酸水解后,木薯淀粉颗粒破坏程度严重,且随水解时间的增加,大部分木薯淀粉颗粒均失去了原有的颗粒形状;经正丁醇-盐酸水解7 d后,木薯淀粉的粒径下降了42.0%。X-射线衍射结果表明正丁醇-盐酸水解木薯淀粉在2θ为20°处出现了衍射峰,证明淀粉在正丁醇-盐酸水解过程中形成了直链淀粉-正丁醇络合物。高效分子排阻色谱和淀粉-碘全波长扫描分析表明：木薯淀粉经过正丁醇-盐酸水解后分子量在4 h内急剧下降,水解4 h后下降趋势减缓,水解3 d后分子量无显著变化并趋于稳定。上述结果表明,采用正丁醇-盐酸水解木薯淀粉3 d为制备糊精的最佳条件。     

免疫磁性糊精微球的制备及快速分离检测单增李斯特菌

研究免疫磁性糊精微球的制备及在快速分离检测单增李斯特菌中的应用。将磁性糊精微球由环氧氯丙烷活化后,与抗体交联制得免疫磁性糊精微球,通过单因素和正交试验对合成条件进行优化。再利用合成好的免疫磁性糊精微球捕获单増李斯特菌,在外加磁场的作用下,富集免疫磁性糊精微球,提取细菌DNA,经过PCR扩增后,进行琼脂糖凝胶电泳。结果表明:活化反应的最佳条件,环氧氯丙烷用量0.4 mL/g,NaOH浓度2.0 mol/L,最佳反应时间5 h;制备免疫磁性糊精微球的最优合成条件:抗体质量浓度1.0 mg/mL,反应温度28℃,反应时间2.5 h;捕获单增李斯特菌时,免疫磁性糊精微球的最佳用量100μL、最佳捕获时间1 h。通过研究得出免疫磁性糊精微球可以快速捕获单增李斯特菌,并能扩增出特异性产物,检出限达到每mL菌液中10个单增李斯特菌。     

包装用木薯黄糊精粘合剂的研制

以木薯淀粉为原料,不同的酸为催化剂,采用焙烘工艺制备木薯淀粉黄糊精,研究了不同种类的酸及酸的添加量、反应温度、反应时间对黄糊精粘度及溶解度的影响,确定了黄糊精工业生产的最佳工艺,并以木薯淀粉黄糊精为主原料,高岭土为填料,成功研制了高强快干环保包装粘合剂。     

微波法制备抗性麦芽糊精的研究

研究了微波制备抗性麦芽糊精的方法,主要以抗性麦芽糊精的含量和白度作为参考指标,在单因素的基础上,选取微波功率、微波时间、加酸量三个因素进行Box-Benhnken中心组合设计,再通过响应面分析法对实验条件进行优化,结果显示:微波功率630W,微波处理时间10.12min,加酸量是6.43%.得到的抗性麦芽糊精的含量43.30%,白度是76.9%.