Reaction behavior of lignin in supercritical methanol as studied with lignin model compounds   总被引：2，自引：0，他引：2  

E.?Minami  H.?Kawamoto  S.?SakaEmail author 《Journal of Wood Science》2003,49(2):158-165

 The reaction behavior and kinetics of lignin model compounds were studied in supercritical methanol with a batch-type supercritical biomass conversion system. Guaiacol, veratrole, 2,6-dimethoxyphenol, and 1,2,3-trimethoxybenzene were used as model compounds for aromatic rings in lignin. In addition, 5-5, β-1, β-O-4, and α-O-4 types of dimeric lignin model compounds were used as representatives of linkages in lignin. As a result, aromatic rings and 5-5 (biphenyl)-type structures were stable in supercritical methanol, and the β-1 linkage was not cleaved in the β-1-type structure but converted rapidly to stilbene. On the other hand, β-ether and α-ether linkages of β-O-4 and α-O-4 lignin model compounds were cleaved rapidly, and these compounds decomposed to some monomeric compounds. Phenolic compounds were found to be more reactive than nonphenolic compounds. These results indicate that cleavages of ether linkages mainly contribute to the depolymerization of lignin, whereas condensed linkages such as the 5-5 and β-1 types are not cleaved in supercritical methanol. Therefore, it is suggested that the supercritical methanol treatment effectively depolymerizes lignin into the lower-molecular-weight products as a methanol-soluble portion mainly by cleavage of the β-ether structure, which is the dominant linkage in lignin. Received: December 19, 2001 / Accepted: April 30, 2002 Acknowledgments This research has been done under the research program for the development of technologies for establishing an ecosystem based on recycling in rural villages for the twenty-first century from the Ministry of Agriculture, Forestry and Fisheries, Japan; by a Grant-in-Aid for Scientific Research (B)(2) (no.12460144, 2001.4–2003.3) from the Ministry of Education, Culture, Sports, Science and Technology, Japan; and under the research program from Kansai Research Foundation for Technology Promotion, Japan. The authors thank them for their financial support. This study was presented in part at the 45th Lignin Symposium, Ehime, Japan, October 2000 and the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, Japan, April 2002 Correspondence to:S. Saka  相似文献   

3种棕榈藤藤材变色的研究   总被引：7，自引：2，他引：7  

吴玉章  周宇 《林业科学》2005,41(5):211-213

棕榈藤(rattan)是热带和亚热带森林中多用途植物,是仅次于木材和竹材的林产品,具有很高的经济价值(许煌灿等,1993;1999)。自古以来,藤主要用来制作家具,在我国藤家具制造业已有100多年的发展历史。藤家具美观、轻便、耐用,深受人们喜爱,产品畅销国内外。但是,藤材的变色影响了藤条的质量和等级,进而影响商品的外观,左右商品的价值。变色原因有多种,生物的(如微生物繁殖)、化学的(如金属离子、酸碱作用)及物理的(如光和热)等(村神哉等,1979;陆文达,1993;村神哉,2002)。藤材变色有霉菌引起的霉变色,还有因藤材及其制品长时间暴露而导致颜…  相似文献   

湘西虎杖抑菌成分提取及其抑菌活性研究初报   总被引：5，自引：0，他引：5  

卢成瑛  黄早成  李翔  钟维 《中国林副特产》2005,(2):1-3

以乙醇作溶剂,对湘西虎杖抑菌活性物提取条件进行研究,通过抑菌实验得到最佳提取条件为A3B2C3,即90%乙醇、60℃、3h, 该条件下的提取物对细菌生长的抑制活性最强,但对酵母菌无明显的效果,对三种受试细菌的最小抑菌浓度(MIC)为0.25~ 0.5g/ml。提取物经85℃、100℃,15 min 或pH2~8 处理后仍具有较强的抑菌活性,其乙酸乙酯萃取物对三个菌都有较强的抑菌活性。  相似文献   

室温粉碎搅拌法从印楝种仁中萃取印楝素的研究   总被引：1，自引：0，他引：1  

李晓升  王有琼  段琼芬  赵吉寿 《中国林副特产》2006,(3):1-3

用快速粉碎搅拌的方法从印楝种仁中萃取印楝素,分别研究了萃取时间、溶剂的选择及用量对印楝素萃取产率的影响。优化的工艺条件为:208g去油后的印楝种仁(相当于300g印楝种仁),以750ml甲醇做溶剂,在快速粉碎搅拌下萃取21min即可以达到最高萃取产率,与微波辅助法、超声波法、浸提法相比,具有提取率高、设备和操作简单、节约溶剂、快速等特点。  相似文献   

Decomposition behavior of woody biomass in water-added supercritical methanol     

Eiji Minami  Shiro Saka 《Journal of Wood Science》2005,51(4):395-400

The chemical conversion of Japanese beech (Fagus crenata Blume) in water-added supercritical methanol was studied for a wide range of water content using a batch-type reaction vessel to obtain chemicals from lignocellulosics. It was consequently found that addition of water enhanced the decomposition of wood cell wall components; cellulose, hemicelluloses, and lignin. In cases of high water content, however, it resulted in low solubility of lignin-derived products causing an increase in the mass of the residue. The water content was thus optimized to be around 10% (v/v) for the decomposition of wood. Concomitantly, the yields and selectivity of the chemicals from wood could be regulated by the addition of water, especially for the lignin-derived products. As a result, the monomeric compounds of lignin, coniferyl alcohol and sinapyl alcohol, were recovered as their γ-methyl ethers in the presence of water in higher yields than those obtained without addition of water.  相似文献   

栀子黄色素浸提条件的优化选择研究   总被引：6，自引：0，他引：6  

陈顺伟  滕水明  柏明娥  庄晓伟 《浙江林业科技》2002,22(6):14-17

应用正交设计 L16（44×23）就栀子黄色素浸提的果实破碎度、浸提次数、浸提温度、浸提时间和液比共 5 个因子与浸取液中栀子黄吸光度、果胶量的相关性进行了试验研究，结果表明果实破碎度和浸提次数为影响光度显著效应因子，果实破碎度和浸提温度为影响胶量显著因子。在此基础上，选择出了果实破碎度 20 目、浸提时间 35 min、浸提温度 20 ℃、液比 4 ml/g、二次浸提为栀子黄色素浸提的较优条件。在此条件下，栀子黄色素浸提所得的液状产品得率为 15.5 %。  相似文献   

印楝提取物防治桑天牛的林间试验   总被引：3，自引：0，他引：3  

陈小平  赵博光  徐学勤 《中国森林病虫》2004,23(1):27-29

以桑天牛成虫Apriona germari Hope喜食的构树为引诱树6株，选取一块与周围树林相对孤立的杨树林为试验地，试验地面积约为0．13hm^2，设引诱树6株，胸径8～10cm。每年1次将2g含30％印楝素的印楝种核提取物配成制剂，注入构树中，进行防治桑天牛林间试验。结果表明：注药前，对照虫株率(57．50％)与处理虫株率(56．41％)之间差异不显著。注药1a后处理林的虫株率下降至38．46％，对照林的虫株率增加到70．00％；2a后，处理林的虫株率下降到23．08％，对照林的虫株率达82．50％。讨论了应用天然化合物防治林木害虫的优点和前景。  相似文献   

Effect of different levels of dietary sweet orange (Citrus sinensis) peel extract on humoral immune system responses in broiler chickens          下载免费PDF全文

Zohreh Pourhossein  Ali Ahmad Alaw Qotbi  Alireza Seidavi  Vito Laudadio  Gerardo Centoducati  Vincenzo Tufarelli 《Animal Science Journal》2015,86(1):105-110

This experiment was conducted to evaluate the effects of different levels of sweet orange (Citrus sinensis) peel extract (SOPE) on humoral immune system responses in broiler chickens. Three hundred 1‐day broilers (Ross‐308) were randomly allocated to treatments varying in supplemental SOPE added in the drinking water. The experimental groups consisted of three treatments fed for 42 days as follows: a control treatment without feed extract, a treatment containing 1000 ppm of SOPE and a treatment containing 1250 ppm of SOPE. All treatments were isocaloric and isonitrogenous. Broilers were vaccinated with Newcastle disease virus (NDV), avian influenza (AI), infectious bursal disease (IBD) and infectious bronchitis virus (IBV) vaccines. Antibody titer response to sheep red blood cells (SRBC) was higher in the group fed 1250 ppm of SOPE (P < 0.05) as well as for immunoglobulin G (IgG) and IgM. Similarly, antibody titer responses to all vaccines were constantly elevated (P < 0.05) by SOPE enrichment in a dose‐dependent manner. Relative weights of spleen and bursa of Fabricius were unaffected by treatments. Dietary SOPE supplementation may improve the immune response and diseases resistance, indicating that it can constitute a useful additive in broiler feeding. Thus, supplying SOPE in rations may help to improve relative immune response in broiler chickens.  相似文献   

Frozen bread dough: Effects of freezing storage and dough improvers   总被引：1，自引：0，他引：1  

Vania Octaviani Selomulyo  Weibiao Zhou 《Journal of Cereal Science》2007

This review focuses on the effects of freezing storage on the microstructure and baking performance of frozen doughs, and provides an overview of the activities of dough improvers, including emulsifiers, hydrocolloids and other improvers used in frozen dough applications. The overall quality of bread baked from frozen dough deteriorates as the storage of the dough at sub-zero temperatures increases due to several factors which are discussed. Lipid-related emulsifiers such as diacetyl tartaric acid esters of mono and diglycerides and sucrose esters employed as anti-staling agents, dough modifiers, shortening sparing agents, and as improvers for the production of high-protein bread have also been employed in frozen doughs. Hydrocolloids are gaining importance in the baking industry as dough improvers due to their ability to induce structural changes in the main components of wheat flour systems during breadmaking steps and bread storage Their effects in frozen doughs is discussed. Other dough improvers, such as ascorbic acid, honey and green tea extract, are also reviewed in the context of frozen doughs.  相似文献   

豚草和三裂叶豚草拮抗植物的筛选     

付开赟  王钿  丁新华  贾尊尊  吐尔逊·阿合买提  张国良  付卫东  文俊  加马力丁·吾拉扎汗  王兰  郭文超 《新疆农业科学》2022,59(12):3030-3046

【目的】 研究豚草(Ambrosia artemisiifolia L.)和三裂叶豚草(Ambrosia trifida L.)浸提液对常用替代牧草高羊茅、早熟禾、黑麦草、披碱草,以及对苜蓿、葵花、玉米、小麦、甜菜种子萌发的影响;筛选对豚草和三裂叶豚草具有防控效果的替代植物以及最佳混种方式。【方法】 采用培养皿滤纸法,研究豚草和三裂叶豚草浸提液对供试种子萌发的影响。采用盆栽竞争试验,运用DeWit取代试验研究法,设置牧草和入侵杂草5种混种方式,混种比例分别为1∶1、1∶2、1∶3、2∶1、3∶1,研究黑麦草、披碱草和高羊茅与豚草和三裂叶豚草的竞争效应,分析3种牧草对豚草和三裂叶豚草的替代控制潜力。【结果】 随着豚草和三裂叶豚草的浸提液浓度的增加,4种常用替代牧草种子和新源县5种主要作物种子发芽率,发芽指数和化感效应指数均下降。5种混种密度下,黑麦草、高羊茅与三裂叶豚草混种比例为3∶1时,三裂叶豚草的竞争平衡指数分别为(-0.505 1±0.301 5)、(-0.757 6±0.265 88)均显著小于0(P<0.05);黑麦草、高羊茅与豚草混种比例为1:3时豚草竞争平衡指数分别为(-0.955 8±0.518 08)、(-2.049 7±0.178 55)均显著小于0(P<0.05)。【结论】 豚草和三裂叶豚草浸提液对供试种子萌发具有化感抑制作用;且浸提液浓度越大抑制作用越强,同时叶部化感抑制作用大于根部。三裂叶豚草对四种牧草种子萌发的化感抑制作用大于豚草。黑麦草和高羊茅可以作为豚草和三裂叶豚草的替代植物。黑麦草和高羊茅防治三裂叶豚草时建议播种比例为3∶1;防治豚草时建议播种比例为1∶3。豚草和三裂叶豚草发生密度较大时其化感抑制作用越强,影响牧草萌发生长,应适当加大替代牧草播种量。  相似文献