正交设计优化石韦多糖的纤维素酶法提取工艺

采用单因素试验和正交试验,以石韦多糖得率为指标,研究pH值、酶用量、酶解温度和时间对石韦多糖提取效果的影响。优选纤维素酶法提取石韦多糖的工艺条件。正交试验结果表明,影响石韦多糖得率的因素次序:酶解温度酶解pH值酶解时间酶用量。得出纤维素酶法提取的最佳工艺条件为:酶解pH6.0,酶用量为8.0mL,酶解温度50℃,酶解时间50min。在优化的条件下进行提取实验,石韦多糖得率为6.58%。说明纤维素酶法提取石韦多糖省时高效,可为石韦多糖的大规模生产提供可借鉴的新方法。     

复合酶协同超声提取葫芦巴中薯蓣皂苷的工艺研究

研究复合酶协同超声提取葫芦巴中薯蓣皂苷的工艺。以葫芦巴中薯蓣皂苷得率为考察指标,通过单因素试验及L_9(3~4)正交试验,探讨纤维素酶、果胶酶复合酶制剂的使用量、酶解时间、酶解温度、pH值对薯蓣皂苷得率的影响,优化复合酶协同超声提取葫芦巴中薯蓣皂苷的工艺条件。结果表明,最佳酶解条件为复合酶制剂用量为2.5%,酶解温度为30℃,pH值为6.0,酶解时间为2h。在此条件下,葫芦巴中薯蓣皂苷的得率为2.29%,经比较,复合酶协同超声提取薯蓣皂苷的得率比直接超声提取增加了36.3%。     

超声波复合酶法提取桦褐孔菌多糖的工艺研究

目的:研究超声波复合酶法用于提取桦褐孔菌多糖的效果。方法:采用超声波复合酶法对桦褐孔菌进行处理,以桦褐孔菌提取物中多糖得率和多糖含量为综合评价指标,考察了超声波复合酶法中主要因素对桦褐孔菌多糖提取效果的影响,并通过正交试验确定出最佳工艺条件。结果:超声波复合酶法提取桦褐孔菌多糖最佳工艺条件:超声时间30min,超声波功率400W,酶解时间40min,酶解温度40℃。结论:超声波复合酶法双重处理可显著提高桦褐孔菌多糖的提取效果。     

纤维素酶法提取葶苈子多糖的工艺研究

优化纤维素酶法提取葶苈子多糖及其纯化。通过单因素实验和正交实验,研究酶解温度、提取时间、酶用量和pH值对葶苈子多糖提取率的影响,并经脱脂、热水抽提、乙醇沉淀、Sevage法脱蛋白得到葶苈子多糖。纤维素酶法提取的优化工艺条件为:pH值为5,加酶量4mL,酶解温度50℃,提取时间1h。在此条件下,葶苈子多糖的提取率平均为4.8%,RSD为0.12%。纤维素酶法提取葶苈子多糖省时高效,多糖的纯化方法简便,易操作,纯度高。     

超声波协同酶解法提取白术总多糖工艺优化

目的应用超声波协同酶解法对白术中总多糖进行提取并进行含量测定,优化白术多糖最佳提取工艺。方法以白术中总多糖含量为指标,分别考察复合酶种类、酶的比例、酶添加量、水浴酶解时间、料液比、超声提取时间、提取方式几个因素对多糖提取率的影响,并采用正交试验对提取工艺结果进行优化。结果在纤维素酶∶果胶酶=2∶1、复合酶添加量为15mg·g~(-1)、水浴酶解50min、超声提取1.25h时白术中总多糖提取率较高,为43.87%,高于不加酶提取白术多糖量的28%。结论该方法提取白术总多糖时间较短、操作简单、节约溶剂,采用硫酸苯酚显色法检测快速、准确,可较好地检测白术多糖含量。     

酶法提取枸杞多糖的工艺研究

研究了酶法提取枸杞多糖的工艺,探讨了酶的种类、 pH值、料液比、酶解温度、酶解时间等对多糖提取率的影响。结果表明：果胶酶的提取效果最好;果胶酶最佳工艺条件为pH值为3.5,料液比为1：45,温度为55℃,时间为2 h,此条件下枸杞多糖的提取率达7.40％。     

星点设计-效应面法优化胰蛋白酶提取鱼腥草多糖的工艺研究

利用星点设计-效应面法对胰蛋白酶提取鱼腥草多糖的工艺进行优化,为鱼腥草多糖的酶法提取提供一定的依据。在单因素的试验基础上以酶的添加量、酶解时间、酶解温度为自变量,鱼腥草多糖含量为因变量,对自变量各水平进行多元线性回归拟合,利用效应面法筛选最佳提取工艺并进行预测分析,采用UV测定多糖含量,检测波长490nm。结果表明：经优化得最佳实验条件为酶添加量2%,酶解时间150 min,酶解温度45℃。在此条件下多糖含量为25.93,与模型预测值相符。利用星点-效应面法优化胰蛋白酶提取鱼腥草多糖工艺的方法简便且预测性良好。关键词：鱼腥草;效应面;多糖;酶提工艺     

正交设计优化连翘多糖的酶提取工艺及抗氧化活性研究

研究连翘多糖最佳提取工艺,为充分利用连翘多糖提供依据。以多糖得率为指标,采用单因素试验、正交试验和方差分析确定纤维素酶提取连翘多糖最佳工艺,通过分光光度法对提取物进行多糖含量测定。采用二苯基-2-三硝基苯肼(DPPH)·自由基、超氧阴离子自由基等不同体外抗氧化模型,探究连翘多糖抗氧化能力。得出纤维素酶法提取优化工艺条件为:pH值为5.0,加酶量6mL,酶解温度50℃,提取时间90min。在此条件下,连翘多糖含量平均为23.10%,相对标准偏差(RSD)为1.93%。连翘多糖对DPPH·自由基和超氧阴离子有清除作用,且呈一定的量效关系。优选出的酶提取工艺简便可行,多糖纯化方法简便,纯度高。所得多糖有一定抗氧化活性。     

酸酶序解法制备高吸水性玉米多孔淀粉的研究

以玉米淀粉为原料,采用酸酶序解法制备了高吸水性玉米多孔淀粉。通过单因素实验和正交实验研究了酸酶序解过程中各主要因素对多孔淀粉吸水性能的影响。确定最佳酸处理条件为:盐酸质量浓度3.0%、淀粉乳质量浓度40%、处理时间70 min、处理温度50℃;最佳酶解条件为:复合酶加量为理论水解量的40%、酶解时间18 h、酶解温度40℃、pH值4.0。用该酸酶序解法制备的玉米多孔淀粉的吸水率为156.98%,比传统的单用复合酶解法提高约20%。     

酶法提取小檗碱工艺研究

用正交实验法研究了酶法提取小檗碱的最佳工艺条件。以小檗碱提取率为指标,分别考察了温度、时间、酶解pH值、加酶量对酶解反应的影响。确定了酶解黄连的最佳工艺条件:温度40℃、时间90 m in、pH 4.0、酶用量30 mg/g。在此条件下,对酶法提取小檗碱与传统乙醇浸提法进行比较,结果表明,酶法提取工艺比传统乙醇浸提法小檗碱产量提高了49%。     

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.     

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。     

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.