茶多酚提取新工艺

茶多酚是一种新型天然食品添加剂和新兴的医药保健品。医药保健用茶多酚的咖啡因含量要求很低,采用本工艺得到的绿茶提取物茶多酚含量≥95％,儿茶素含量≥70％,咖啡因含量≤0.5％～1％,达到或超过医药保健用茶多酚产品的要求。     

低咖啡因茶多酚提取新工艺研究

茶多酚是一种新型天然食品添加剂和新兴的医药保健品。医药保健用茶多酚对产品质量要求较高，采用本工艺得到的绿茶提取物茶多酚含量≥９５％，儿茶素含量≥７０％，咖啡因含量≤０．５％￣１％，达到或超过医药保健用茶多酚产品的要求。     

茶多酚冷浸提、热提对比分析及纯度测定

本文设计的茶多酚冷提法(高浓度乙醇冷浸渗漏提取法)相对于常用的超声提取法、微波提取法等具有操作简单、设备要求低等优势,用所建立的高效液相色谱法测定冷提液和普通热提液中茶多酚的含量,结果表明:采用冷提法从10. 0 g安康紫阳富硒绿茶中得到的冷提液中茶多酚的含量达到了2. 3033 g;采用二级萃取和二级柱分离方法纯化后,茶多酚的得率为14. 62%,纯度为84. 69%;热提液中茶多酚的含量为1. 4740 g,纯化后茶多酚的得率为10. 61%,纯度为92. 02%。     

微波法提取沙棘茶中茶多酚的工艺研究

用微波法提取沙棘茶中茶多酚,考察了乙醇浓度、微波功率、加热时间、料液比对茶多酚含量的影响。结果表明,微波法提取茶多酚的最佳工艺参数为乙醇浓度50%,微波功率640 W,加热时间50 s,料液比1∶60,在此条件下,茶多酚含量可达16.9%。     

从雷竹叶中提取茶多酚及其红外光谱的研究

以雷竹叶为原料,按设计的工艺条件,用乙醇提取茶多酚,乙酸乙酯萃取,回收溶剂,大孔树脂精制产物。得到竹叶中的粗茶多酚的含量13.4%,精茶多酚含量为2.60%。以没食子酸为标品、进行提取物及精制茶多酚的红外测试,对其基团归属予以认定,确定产物成分。     

茶多酚含量与儿茶素含量关系研究

研究了不同规格茶多酚产品中表没食子儿茶素(EGC)、儿茶素(DL-C)、表没食子儿茶素没食子酸酯(EGCG)、表儿茶素(EC)、没食子儿茶素没食子酸酯(GCG)、表儿茶素没食子酸酯(ECG)6种儿茶素含量及其总量与茶多酚含量的关系.结果发现,对于同种规格用同种原料和同种工艺生产的茶多酚产品,其茶多酚含量与6种儿茶素总量成一定的比例关系.茶多酚含量用酒石酸亚铁分光光度法测定,儿茶素含量用高效液相色谱法测定.     

黑茶中茶多酚的提取及其含量测定方法的研究进展

茶多酚具有抗氧化、降血脂、降血糖、抗辐射等多种功能,在食品、医药、日化、保健等方面具有广泛的应用前景。本文综述了目前常用的几种黑茶中茶多酚的提取及含量测定技术,并对这些方法进行了阐述和比较,最后对茶多酚的提取及含量测定方法研究前景进行了展望。     

不同种类茶叶中茶多酚含量的测定

采用离子沉淀法,对不同种类茶叶中的茶多酚含量进行测定。分别考察了不同酸度、浸提温度及浸提时间对测定茶多酚含量的影响,确定以3价铁离子作为沉淀剂时,浸提时间为30 min,料液比低于或等于1∶15,pH为8或9,借助分光光度法测得不同品种茶叶中茶多酚的含量。结果表明:花茶的茶多酚提取率为1.63%,绿茶的茶多酚提取率为5.27%,红茶的茶多酚提取率为1.37%。     

茶树花中功能性成分的提取与分析研究

采用分光光度法测定茶多酚、茶多糖等功能性成分含量;用高效液相色谱法测定茶多酚中儿茶素组成成分,离子色谱积分安培法测定多糖中单糖的组成成分。实验表明:茶树花中含茶多酚含量为3.62%~4.48%,总糖为16.15%~23.25%,其中茶多糖为1.60%~1.65%,茶氨酸为3.92%~5.03%,黄酮为0.141%~0.162%。分析结果表明茶树花中功能性成分与茶叶中的成分相似,为进一步开发利用茶树花资源提供理论依据。     

药用级蒙脱石的提纯研究与表征

对某钙基膨润土进行物理提纯试验,确定湿法提纯有利于得到高纯度蒙脱石。车间采用二次旋流分力分级法提纯得到了蒙脱石含量≥95%的提纯精矿,通过物理化学性能测试、XRD、电镜等表征,该提纯土达到了医药蒙脱石要求。     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

Insect antifeedant properties of anthranoids from the genusVismia

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.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

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.