芝麻叶中总黄酮的最佳提取工艺研究

该文测定了芝麻叶中总黄酮的含量，并对芝麻叶黄酮的提取工艺进行了研究。重点探讨了采用乙醇提取法和微波处理与乙醇提取相结合的方法提取芝麻叶黄酮类化合物的最佳工艺条件。试验结果表明：芝麻叶中总黄酮的含量为0.98%；乙醇提取法的最适工艺参数是浸提剂乙醇浓度为80%、浸提温度为80℃、料液比为1∶25、浸提时间为2.5 h，如此条件可使黄酮提取率达95.6%；微波处理与乙醇提取相结合的方法的最适工艺参数是微波功率200 W、微波处理时间70s，乙醇浓度为80%、浸提温度为80℃、料液比为1∶25、浸提时间为30 min，这种工艺可使黄酮提取率达95.8%。     

苹果渣多酚提取工艺的优化

为优化苹果渣中多酚提取工艺,并得到提取工艺和多酚组成之间的关系,利用微波辅助提取法设计了由物料颗粒、液料比、乙醇浓度、微波功率和微波提取时间5个因素构成的多酚提取优化试验流程,构建了涵盖黄酮、原花青素2种典型多酚物质和抗氧化能力的提取工艺评价指标体系。采用证据理论对不同工艺在评价指标下的焦元进行识别,并基于信度函数和似真函数得到了不同提取工艺的效用区间和优化方案。优化结果为：物料颗粒60目,液料比30?mL/g,乙醇体积分数60%,微波功率600?W,提取时间70?s,此条件下苹果渣多酚的提取量为213.83?mg/100g,黄酮提取量为83.21?mg/100g,原花青素提取量为52.79?mg/100g,抗氧化的EC50值为3.71?mg/100mL,验证了采用证据理论进行苹果渣多酚提取工艺优化的有效性。     

黑苦荞米黄酮提取工艺优化及其降血糖活性研究

为了获得合适的黑苦荞米黄酮提取工艺,该文采用单因素试验和响应面设计,选择乙醇体积分数、料液比、提取时间、提取温度4个因素,优化黑苦荞米黄酮提取工艺。试验结果表明,黑苦荞米黄酮的最佳提取条件是:乙醇体积分数54%,料液比1:24 g/m L,提取时间62 min,提取温度71℃。在此条件下,理论黄酮得率为2.21%,实际黄酮得率为2.20%,相对误差为0.45%。在此基础上进一步研究了黑苦荞米黄酮的α-淀粉酶抑制活性,结果表明7.5 mg/m L的黑苦荞米黄酮对α-淀粉酶活性的抑制率为54.05%,与二甲双胍(5 mg/m L)效果相当;此外,与空白对照相比,50μg/m L黑苦荞米黄酮能显著(P0.05)提高肝脏细胞Hep G2的葡萄糖消耗量(48.73%),并促进肝脏细胞糖原的合成。研究结果表明,黑苦荞米黄酮具有较好的辅助降血糖功效。     

枳实副产物中柠檬苦素最佳提取条件的研究

通过单因素试验和旋转正交试验对枳实副产物中柠檬苦素的提取工艺进行优化。结果表明：最佳提取工艺参数为提取剂乙醇浓度78％、pH值6.5、料液比1∶6(w/v)、浸提温度60℃、提取时间2 h，该条件下柠檬苦素的提取率为94.2％。     

秀丽槭叶总黄酮的提取及其抗氧化能力研究

为开发和利用秀丽槭叶中的黄酮资源,利用响应面分析法优化乙醇-超声法提取秀丽槭叶中总黄酮的工艺,并分析总黄酮清除DPPH自由基能力和总抗氧化能力。结果表明,在超声功率200 W条件下,秀丽槭叶总黄酮适宜的提取工艺条件为:提取温度55℃、乙醇浓度70%、液料比50∶1(v/w)、提取时间48 min,该条件下提取到的秀丽槭叶总黄酮含量为58.664 mg·g-1,秀丽槭叶总黄酮清除DPPH自由基的EC50为0.528 mg·L~(-1),清除率可达95.56%;秀丽槭叶总黄酮在相同条件下较L-抗坏血酸具有更强的总抗氧化力。本研究结果为今后秀丽槭叶黄酮资源的开发利用提供了一定的科学依据。     

基于UPLC-QTOF-MS解析苦荞黄酮组成及药理学网络分析

为优化苦荞黄酮提取工艺并明确其具体成分结构和含量及药理作用,本研究以四川省凉山彝族自治州甘洛县优质苦荞为研究对象,对超声提取苦荞黄酮工艺进行了优化,采用超高效液相色谱-四级杆-飞行时间质谱(UPLC-QTOF-MS)对主要黄酮成分进行结构鉴定,并采用超高效液相色谱-三重四级杆质谱联用仪对鉴定到的黄酮进行准确定量,同时利用中药系统药理学(TCMSP)系统分析其网络药理学特性。结果表明,超声辅助乙醇提取苦荞黄酮的最优条件为乙醇浓度90%(V/V)、超声功率140 W、超声温度70℃、超声时间60 min、提取溶剂与苦荞原料比50∶1(mL·g^-1),该条件下,提取液中共鉴定到黄酮16种,其中芦丁、表儿茶素和儿茶素含量分别达到115.81、72.99和23.08μg·mL^-1。这16种黄酮在防治心血管疾病、慢性炎症性疾病上具有重要作用。本研究可为苦荞精深加工综合利用尤其是功能性苦荞产品开发利用奠定基础。     

微波辅助萃取-大孔树脂分离纯化芳樟叶黄酮

为了综合利用芳樟叶精油提取过程中产生的大量残渣,该文利用微波辅助萃取和大孔树脂选择性吸附来分离纯化芳樟叶黄酮。采用L9(34)正交试验,考察了萃取剂、微波辐射功率、辐射时间及料液比对黄酮得率的影响,确定了微波辅助萃取的优化工艺条件:以60%乙醇做萃取剂,微波功率320W,间歇辐射2次,每次1min,料液质量体积比1:12,在此条件下,芳樟叶黄酮的提取得率为2.97%,与乙醇热回流提取方法相比,得率提高了6.83%,时间缩短了98.89%;为进一步纯化萃取所得的黄酮提取物,选择6种大孔吸附树脂,测定芳樟叶黄酮在树脂上的吸附量和解吸率,筛选出了吸附剂HPD-450,其对芳樟叶黄酮有较好的静态吸附和解吸效果。经装填有大孔树脂HPD-450的固定床纯化后黄酮纯度由22.49%提高到51.28%,纯化倍数2.3倍。     

闪式提取油茶枯饼中茶皂素的工艺优化

为了研究闪式提取油茶枯饼中茶皂素的工艺,在单因素试验基础上,选取乙醇体积分数、提取时间、液料比3个因素,利用Box-Benhnken中心组合试验和响应面分析法对提取工艺进行优化。结果表明,闪式提取茶皂素的较佳工艺条件为：乙醇体积分数78%、提取时间40 s、液料比20 mL/g。在此条件下,茶皂素得率为21.09%±0.26%,与模型预测值基本相符。与传统乙醇热回流提取方法相比,闪式提取方法茶皂素得率略有提高,提取时间由6 h缩短为40 s,提取温度由70℃降到20～25℃。该方法是一种较为理想的茶皂素提取方法。     

仙人掌皮黄酮提取工艺优化(简报)

仙人掌皮黄酮提取可提高废弃物的资源利用和活性成分的开发。采用响应面分析法对乙醇体积分数、提取温度、提取时间和剂料比等提取条件进行了优化。结果表明,曲面回归方程拟合性好;优化工艺为乙醇体积分数67%、提取温度76℃、提取时间5.7 h、剂料比21.4 mL/g时,仙人掌皮黄酮得率为6.45 %。经鉴定仙人掌皮中主要黄酮为异鼠李素-3-O-[2-O,6-O-双-?-L-鼠李糖基]-?-L-葡萄糖苷、异鼠李素-3-O-（6?-鼠李糖）葡萄糖苷。     

微波辅助提取多穗柯嫩叶黄酮工艺研究

该研究比较了微波辅助水提(MW)、微波辅助氢氧化钙溶液提取(MCW)、水提(W)、氢氧化钙溶液提取(CW)、乙醇回流(E)和甲醇回流(Me)等工艺提取多穗柯黄酮的效果,用正交设计筛选MCW工艺条件,并对材料预煮与微波处理时间的关系、氢氧化钙溶液浓度对提取效果的影响进行了探讨。结果表明,MCW提取效果明显优于W、CW、MW和E或Me;材料预煮和适当的氢氧化钙浓度可以明显提高MCW黄酮提取效果;研究得出的最佳工艺条件为：1.2%氢氧化钙水溶液,固液比1∶12,预煮时间5 min,高档功率微波处理25 min。此工艺提取率达到96%,提取物黄酮含量达到37%,是一种高效、无污染的提取多穗柯黄酮工艺。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.