魔芋中KGM的提取及抑菌活性分析

以鲜魔芋为原料,对乙醇沉淀法提取KGM的工艺条件进行研究,探讨了乙醇浓度、水溶胶浓度、溶胀温度和洗涤次数对KGM提取率的影响,并研究了KGM抑菌活性。结果表明,当水溶胶浓度为0.5%、溶胀温度为60℃、沉淀乙醇浓度为50%、洗涤2次时,KGM提取率可达81.8%;提取后的KGM对大肠杆菌和金黄色葡萄球菌表现出一定的抑菌效果。     

荷叶多酚化学成分提取工艺优化研究

通过利用乙醇提取荷叶中的总多酚,采用正交试验优化乙醇体积分数、提取时间、提取温度、pH值以及料液比等提取条件,结果表明,乙醇体积分数为90％,提取温度为60℃,提取时间为90min,提取pH为5,料液比为1:45(g:mL)时,荷叶总多酚的提取率最高,可达2.395％.     

超声条件下碱提取酸沉淀法从槐米中提取芦丁的研究

以新鲜的槐米为原料,65℃下充分干燥,研细后采用超声条件下碱石灰煮沸盐酸酸化沉淀法来提取芦丁。探讨了反应温度、反应液的pH值、溶剂用量及反应时间对产物芦丁提取率的影响。得出提取的最佳条件为:控制反应温度为70~75℃,碱提取时pH=9、酸沉淀时pH=4,溶剂用量以6倍于原料为宜,提取3次,反应时间3.5 h。制得的芦丁为浅黄色针状晶体,提取率17.83%,熔点176~178℃。     

响应面法优化超声辅助提取荷叶总生物碱

采用超声辅助从荷叶中提取荷叶总生物碱,采用单因素实验考察了提取溶剂、溶剂pH值、料液比(g∶mL)、溶剂体积分数、提取时间和提取温度对荷叶总生物碱提取率的影响,采用响应面法优化了荷叶总生物碱的提取工艺条件。优化的工艺条件为:溶剂pH值2.0、提取温度70℃、料液比1∶32.1(g∶mL)、乙醇体积分数71.1%、提取时间65.31min,在该条件下,总生物碱的提取率达到5.06%。     

正交实验优化火龙果果皮红色素超声辅助醇提工艺

采用超声辅助乙醇浸提法提取火龙果果皮红色素,考察乙醇浓度、料液比、提取时间、提取温度对火龙果果皮红色素提取率的影响。结果表明,各因素影响主次顺序为料液比>乙醇浓度>提取时间>提取温度,最佳工艺条件为:提取剂为30%乙醇,料液比1∶50(g/m L),超声时间30 min,提取温度40℃。采用此最佳工艺条件提取火龙果果皮色素提取率为0.071%。     

鲜龙牙百合淀粉的提取工艺研究

分别采用醇沉水洗法和水提沉淀法提取鲜龙牙百合淀粉,以淀粉提取率为指标,考察了料液比、沉淀时间和乙醇浓度等因素对提取效果的影响。确定了醇沉水洗法提取鲜龙牙百合淀粉的最佳条件为:沉淀时间12h、乙醇浓度60%、料液比2∶10(g∶mL);水提沉淀法提取鲜龙牙百合淀粉的最佳条件为:沉淀时间90min、料液比2∶8(g∶mL)。其中水提沉淀法淀粉提取率相对较高。     

响应面法优化超声辅助提取金银花中绿原酸

采用超声辅助乙醇从金银花中提取绿原酸,通过单因素实验考察pH值、料液比、乙醇体积分数和提取时间对绿原酸提取率的影响,采用响应面法优化提取工艺条件。确定最佳工艺条件为:pH值5.2、提取时间21min、乙醇体积分数63%、料液比1∶13.5(g∶mL)。在该优化条件下,绿原酸的提取率达到10.862%。     

正交实验优化火龙果果皮红色素超声辅助醇提工艺

采用超声辅助乙醇浸提法提取火龙果果皮红色素,考察乙醇浓度、料液比、提取时间、提取温度对火龙果果皮红色素提取率的影响。结果表明,各因素影响主次顺序为料液比乙醇浓度提取时间提取温度,最佳工艺条件为:提取剂为30%乙醇,料液比1∶50(g/m L),超声时间30 min,提取温度40℃。采用此最佳工艺条件提取火龙果果皮色素提取率为0.071%。     

响应面法优化刺玫果总黄酮超声辅助酶法提取工艺

以刺玫果总黄酮提取率为考核指标,采用单因素实验考察酶种类及用量、乙醇体积分数、溶液pH值、料液比、提取温度、提取时间、超声功率、超声温度、超声时间、提取方式等对提取效果的影响;在此基础上,采用响应面法优化刺玫果总黄酮的超声辅助酶法提取工艺,确定最优工艺条件为:纤维素酶用量15 mg·g~(-1)、乙醇体积分数60%、溶液pH值5、料液比1∶15(g∶mL)、提取温度50℃、提取时间2.0 h、超声功率450 W、超声温度50℃、超声时间40 min,在此条件下,刺玫果总黄酮提取率达到128.6 mg·g~(-1)。     

葫芦巴中总黄酮回流提取工艺研究

采用乙醇回流提取葫芦巴中的总黄酮,考察了乙醇浓度、料液比、温度、时间对总黄酮提取率的影响。结果表明,葫芦巴中总黄酮最佳提取工艺参数为:料液比1∶50 g/mL,乙醇浓度40%,提取时间0.5 h,提取温度50℃。在该条件下,总黄酮提取率为1.017%。     

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.     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

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.     

2007～2008年世界塑料工业进展

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.     

2005～2006年国外塑料工业进展

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。