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从箬竹叶中提取茶多酚的研究 总被引:17,自引:0,他引:17
研究了从箬竹叶中提取茶多酚的工艺;探讨了茶多酚的提取方法及相应的提取条件;利用UV-9200型分光光度计对提取产物茶多酚含量进行测定。通过对溶剂选择及用量、提取时间、提取温度等影响因素的研究,确定了茶多酚提取的最适宜的工艺条件:乙醇浓度65%,溶剂用量与箬竹叶用量之比为6—7倍(mL/g),提取温度55℃,萃取次数3—4次,提取时间4—5h,在此条件下茶多酚得率为0.68%。 相似文献
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摘要:以绿茶为原料,水为浸提溶剂,采用离子沉淀法对茶叶中茶多酚的提取进行了研究。探讨了沉淀剂种类、沉淀剂用量、溶剂用量、浸提温度、浸提时间5个因素对茶叶中茶多酚提取的影响,优化了茶多酚提取的最佳工艺条件。结果表明,当以AlCl3为沉淀剂且m沉淀剂:m茶叶=1:5、溶剂用量m茶叶:m水=1:20、浸提温度为水浴75℃、浸提时间45min时,茶多酚的提取率最高,为14.12%。 相似文献
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贯叶连翘提取物及其制剂是北美和欧洲最畅销的抗抑郁植物药,大量临床研究证实其对中,轻度抑郁症有效,且副作用较传统的化学抗抑郁药轻微。新的研究表明,其有效成分具有抗病毒,抗癌抗肿瘤以及治疗肝炎,白血病等多种药理作用。文章综合运用超声波提取法,通过单因素实验,分别考察了提取溶剂的用量,提取溶剂的浓度,提取温度,提取时间对提取效率的影响。再以提取溶剂的用量,提取溶剂的浓度,提取温度,提取时间四因素为指标,设计正交实验。研究结果表明影响贯叶连翘中黄酮提取的主次因素为提取溶剂的浓度〉提取温度〉提取时间〉提取溶剂的用量,其最佳提取工艺条件为用10倍用量的50%乙醇,在50℃温度下提取40 min,在该条件下提取贯叶连翘所得黄酮含量为15.8%。优选出的最佳提取工艺条件,为开发贯叶连翘中抗抑郁有效成分提供了一个科学、合理的理论依据。 相似文献
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超声波协助提取茶多酚的工艺研究 总被引:5,自引:0,他引:5
研究了在超声波协助下采用正交设计法优选茶多酚的提取工艺。结果表明,影响茶多酚提取率的最佳工艺条件为:浸提温度70℃;时间1.5 h;料液比20∶1;乙醇浓度70%。影响茶多酚含量的最佳工艺条件为:浸提温度80℃;时间1.5 h;料液比15∶1;乙醇浓度70%。这些结果为改善茶多酚的提取条件提供了实验基础。 相似文献
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香椿叶中总黄酮的提取工艺研究 总被引:2,自引:0,他引:2
研究了溶剂法提取香椿叶总黄酮的工艺条件。在单因素试验的基础上,用正交实验法对香椿叶总黄酮的提取工艺进行优选,考察乙醇体积分数、固液比、提取时间、浸提温度对香椿叶总黄酮提取率的影响。结果表明,在浸提3次条件下,得到叶片总黄酮最佳工艺条件为:乙醇浓度80%、固液比为1∶10(g/mL)、提取温度80℃、提取时间2 h,在此条件下香椿叶片总黄酮提取率为61.13%;叶轴总黄酮最佳提取条件为:乙醇浓度70%、固液比为1∶10(g/mL)、提取温度80℃、提取时间1 h,在此条件下香椿叶轴总黄酮提取率为71.71%。 相似文献
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茶多酚、茶多糖和茶氨酸的联合提取工艺研究 总被引:1,自引:0,他引:1
以日照绿茶为实验原料,利用水溶剂提取法,通过正交实验及单因素平行实验的方案,分析了料液质量比、浸提时间和浸提温度对茶多酚、茶多糖和茶氨酸联合萃取效果的影响;通过对萃取剂选择以及离子交换树脂的吸附性能研究,确定了茶多酚、茶多糖和茶氨酸联合分离提取的工艺。实验结果表明:该工艺可有效地从茶叶中提取茶多酚、茶多糖和茶氨酸,茶多酚的提取率为13.85%;茶多糖的提取率为1.76%;茶氨酸的提取率为0.19%。 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria. 相似文献
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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively.
There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized.
High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without
the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of
fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to
achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic
SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve
F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender
particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing,
and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing
or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually
preserves suspension stability during freezing.
Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago,
IL. Tied for first place in The John A. Gordon Best Paper Competition. 相似文献
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Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US
In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae
and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted
in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures
(release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species
(Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species
to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were
exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of
separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles
from the southeastern region of the US. 相似文献
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Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed. 相似文献
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中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
收集了2007年7月~2008年6月世界塑料工业的相关资料,介绍了2007~2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍. 相似文献
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中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
收集了2005年7月~2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。 相似文献