共查询到20条相似文献，搜索用时 62 毫秒
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为了优选黄芪多糖提取的工艺,分别用水提醇沉法、微波提取法提取黄芪多糖,比较两种工艺提取黄芪多糖的提取率和提取时间,并采用紫外分光光度法测定黄芪多糖含量。结果:水提醇沉法的黄芪多糖提取率4.468%,含量29.40%;微波提取法的黄芪多糖提取率4.502%,含量31.25%。试验结果表明:微波提取法具有省时、高效、节能等优点,在提高黄芪多糖产率和有效缩短提取时间等方面优于传统的水提醇沉法,是获得较高黄芪多糖提取率及含量的方法。 相似文献
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以麦冬总多糖百分含量为指标,采用正交设计对用热水浸提醇沉法提取麦冬多糖的工艺条件进行了优选研究。在提取过程中,根据单因素实验确定了醇沉时乙醇的用量为浓缩液体积的5倍,含量测定时的最佳显色时间为15min;设计L9(33)正交实验,利用苯酚-硫酸法进行含量测定,重点考察加水量、提取温度和提取次数对提取效果的影响。结果显示提取麦冬多糖的优选工艺条件为加12倍量水,70℃水浴,提取3次,总多糖含量为67.83%。 相似文献
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本文以二型鳞毛蕨为原料,用水提醇沉法从二型鳞毛蕨粉中提取粗多糖,并对提取工艺条件的优化进行了初步探索。结果表明,二型鳞毛蕨粉中提取粗多糖的较佳工艺条件是:浸提温度80℃,料液比1∶30(g/ml),浸提时间2.0h,醇沉溶剂用无水乙醇,醇沉时间24h。在此工艺条件下二型鳞毛蕨多糖的提取率为2.51%。采用硫酸-苯酚比色法,以葡萄糖为标准品,测得二型鳞毛蕨中多糖含量为2.64%。 相似文献
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平菇多糖的提取及含量测定 总被引：1，自引：0，他引：1
对平菇多糖的提取工艺进行了研究,比较了温度、料液比、浸提时间、醇沉浓度四因素对多糖的溶出情况。采用四因素四个水平正交设计优化提取条件,蒽酮—硫酸法来测定多糖,并对试验结果进行方差分析和多重比较。结果表明:提取温度、料液比、提取时间和醇析浓度均对平菇多糖的得率有显著性的影响,通过水平之间的比较最终确定了平菇多糖提取的最佳工艺条件为:温度为100℃、料液比为1:30、提取7h、醇沉浓度为90%,该条件下多糖得率为6.48%,换算因子f=2.4917,稳定性实验得相对标准偏差RSD=0.18%。 相似文献
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微波辅助萃取百合多糖的工艺研究 总被引：1，自引：0，他引：1
目的:以龙牙百合中多糖的得率为指标,研究探讨微波辅助萃取技术在百合多糖提取工艺中的应用.以确定最佳提取工艺.方法:水提醇沉法提取百合多糖,Sevag法(用氯仿和正丁醇按5:1的比例进行萃取)除蛋白质,硫酸-苯酚比色法测总糖含量,采用正交实验对微波辅助萃取技术提取工艺进行优选.结论:实验表明,微波辅助萃取百合多糖的优选工艺条件为:干燥百合粉碎过100目筛;提取功率为700W;提取温度75℃:提取时间25min.百合多糖的得率为3.41%. 相似文献
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响应面法优化代代花多糖提取工艺 总被引：1，自引：0，他引：1
《南阳师范学院学报》2018,(1):35-39
为了探究代代花多糖的最佳提取工艺,在提取时间、温度、料液比三个单因素试验的基础上,通过Box-Behnken中心组合试验设计及响应面法分析建立二次回归模型,以代代花多糖提取率为响应值,对料液比、提取时间和温度进行优化组合,再利用水浸醇沉法提取代代花多糖,得出最佳提取工艺条件.结果表明:在提取时间2 h、温度70℃、料液比1∶100(g/m L)时代代花多糖的提取率预测值为8.82%,实测值为8.81%,两者相差极小,说明该工艺条件比较好. 相似文献
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金针菇多糖的提取及清除羟自由基活性研究 总被引：1，自引：0，他引：1
采用水提醇沉法研究金针菇多糖的提取工艺条件,得到金针菇多糖最佳提取条件为:提取温度80℃、料液比为1:30、提取时间3h、提取2次。对金针菇多糖清除羟自由基的能力进行研究,结果表明金针菇多糖在体外有较好的抗氧化活性。 相似文献
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本文研究了黑糯玉米多糖的提取及两种脱蛋白分离工艺的比较.采用热水浸提、醇沉法提取黑糯玉米多糖,用两种改进的方法(氯仿-正丁醇法和三氯乙酸-正丁醇法)脱除蛋白质,以脱蛋白率为指标,通过正交实验L9(34)确定最佳脱蛋白分离工艺后,对比两种方法的最佳组合粗多糖得率及510nm处吸光值的差异.结果表明:三氯乙酸-正丁醇法比氯仿-正丁醇法的脱蛋白效果好,最佳水平脱蛋白率为70.69%,多糖得率仅为67.87%;氯仿-正丁醇法最佳水平脱蛋白率为51.39%,多糖得率为80.31%.本文建立的优化工艺可为黑糯玉米多糖的分离制备提供参考. 相似文献
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黄花菜富含多糖成分,可分别采取水提醇沉法、微波提取法、超声波提取法、微波处理-水提醇沉法和超声波处理-水提醇沉法5种提取方法,并采用苯酚-硫酸法测定多糖含量。结果表明,其中4种提取方法存在显著差异,以微波提取法效果最佳,其后依次为优化后的超声波处理-水提醇沉法、超声波提取法、水提醇沉法。微波提取法是黄花菜多糖提取的理想方法,优化后的超声波处理-水提醇沉法也不失为黄花菜多糖提取的一种良好方法。 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献