真空耦合超声波提取龙牙■木皂苷及其抗氧化和抑菌活性研究

采用响应面优化真空耦合超声波提取龙牙楤木皂苷的工艺条件,并对比研究真空耦合超声波提取技术、常压超声辅助技术、溶剂提取技术对龙牙楤木皂苷抗氧化活性和抑菌活性的影响。结果表明,真空耦合超声波提取技术最佳工艺为乙醇溶液体积分数80%、料液比1∶25 g/mL、超声温度58℃、超声时间50 min、超声功率270 W、真空度0.08 MPa,在此条件下,龙牙楤木皂苷得率为4.18%,该方法与常压超声辅助技术、溶剂提取技术相比,可提高皂苷得率并明显缩短提取时间。抗氧化活性试验表明,真空耦合超声波技术提取的龙牙楤木皂苷体外抗氧化活性显著(P0.05)高于常压超声辅助技术和溶剂提取技术制备的龙牙楤木皂苷,其中真空耦合超声波技术制备的龙牙楤木皂苷对DPPH自由基的IC_(50)值为0.344 mg/mL,对超氧阴离子由基的IC_(50)值为1.367 mg/mL,总还原能力OD值最大为0.893。抑菌活性试验表明,龙牙楤木皂苷对大肠杆菌、金黄色葡萄球菌有抑制效果,对枯草芽孢杆菌无抑制效果,其中真空耦合超声波提取龙牙楤木皂苷抑菌效果最好,对大肠杆菌最小抑菌浓度为2.5 mg/mL,对金黄色葡萄球菌最小抑菌浓度为10 mg/mL。     

龙牙楤木多糖复合酶法提取工艺优化及抗氧化活性研究

目的：优化龙牙楤木多糖复合酶法提取工艺,提高其抗氧化活性。方法：以纤维素酶、果胶酶和木瓜蛋白酶为复合酶提取龙牙楤木多糖,以酶解温度、酶解时间、料液比为自变量,通过Box-Behnken中心组合法设计三因素三水平试验方案,并通过测定自由基清除能力考察龙牙楤木多糖的抗氧化活性。结果：复合酶法提取龙牙楤木多糖的最佳工艺条件为：酶解温度54 ℃,酶解时间160 min,料液比（m_{龙牙楤木粗粉}∶V_纯化水）1∶31 （g/mL）,此条件下龙牙楤木多糖平均提取率为（10.68±0.05）%,与模型预测值10.78%接近;抗氧化试验表明龙牙楤木多糖对DPPH自由基及羟基自由基的IC₅₀值分别为2.00,3.05 mg/mL,且清除作用均随多糖质量浓度的增大而升高,清除率最大值分别为78.10%,70.10%。结论：该复合酶法工艺条件提高了龙牙楤木多糖提取率;龙牙楤木多糖具有良好的抗氧化活性。     

龙牙楤木中酚类物质提取方法的比较

为筛选适合龙牙楤木中酚类物质的提取方法。本文以龙牙楤木嫩叶为原料,采用溶剂浸提法、溶剂回流法、超声辅助法、微波辅助法以及复合酶法提取龙牙楤木嫩叶中酚类物质,对酚类物质的得率进行比较分析,筛选出最佳提取方法,并在其单因素基础上,进一步利用正交试验优化各工艺参数。结果表明,五种提取方法中复合酶法提取酚类物质效果最好;正交试验得到复合酶法提取的最佳工艺参数为:复合酶（果胶酶和各种碳水化合物酶组成）用量120 μL/g（酶量/样品量）,酶解温度50 ℃,酶解pH6,酶解时间1.5 h,乙醇体积分数50%,此条件下龙牙楤木中总酚得率为7.24%,总黄酮得率为3.17%。通过正交实验优化复合酶法提取龙牙楤木嫩叶中酚类物质,在最佳工艺参数下提取的效果理想,可用于后续对酚类物质纯化、鉴定等研究。     

莪术挥发油酶法提取工艺及抗氧化活性研究

试验旨在研究纤维素酶辅助水蒸气蒸馏法提取莪术挥发油的工艺,并探究其抗氧化活性。在单因素试验结果基础上,以酶添加量、酶解pH及酶解时间为自变量,挥发油得率为响应值,利用Box-Behnken响应面法进行工艺优化。以DPPH和羟自由基清除率为指标考察莪术挥发油的体外抗氧化活性。纤维素酶酶解提取莪术挥发油的最佳工艺为酶添加量1.6%、酶解pH 4.6、酶解时间2.1 h、酶解温度50℃、料液比1∶10 g/mL,此条件下挥发油得率为5.24%,显著高于水蒸气蒸馏法得率2.17%。莪术挥发油对DPPH和羟自由基具有较强的清除作用,半数抑制浓度分别为0.783 mg/mL和0.814 mg/mL。纤维素酶辅助提取法可显著提高莪术挥发油得率,工艺简便可行,获得的莪术挥发油具有抗氧化活性。     

山银花多糖提取工艺优化及其抗氧化活性研究

目的:研究纤维素酶提取山银花多糖的最佳工艺条件,并探讨其体外抗氧化活性。方法:以山银花多糖得率为响应值,在单因素试验基础上,以酶解时间、液料比、酶解p H、酶添加量为试验因素,采用响应面法建立数学模型,筛选最佳提取工艺条件。山银花多糖抗氧化活性检测使用DPPH、·OH和O_2~-·自由基清除能力体系。结果:纤维素酶酶解提取山银花多糖最佳条件为:酶解时间80 min,液料比14.6 mL/g,酶解pH 5.2,酶添加量8.0 mg/mL,酶解温度50℃,在此条件下山银花多糖实际得率为15.76%,与理论预测值16.05%相对误差小于5%。液料比对多糖得率影响最显著,酶添加量、酶解pH次之,酶解时间影响最小。山银花多糖具有较强的抗氧化活性,对DPPH、·OH和O_2~-·自由基清除的半数抑制浓度IC_(50)分别为0.941、1.238、1.786 mg/mL。结论:获得山银花多糖纤维素酶酶法提取的最佳条件,该工艺条件方便可行,获得的多糖具有较强的自由基体外清除能力。     

超声波结合酶法提取葡萄皮渣原花青素工艺优化及其抗氧化活性

以葡萄皮渣为试材,在单因素试验的基础上,通过L9（34）正交试验对超声波结合酶法提取酿酒葡萄皮渣原花青素的工艺条件进行优化,并对其抗氧化性进行研究。最佳工艺参数为纤维素酶（500 000 U/g）添加量0.30%、酶解温度55℃、酶解时间90 min、超声时间30 min、超声功率400 W。在最佳工艺参数下葡萄皮渣中原花青素的得率为14.22 mg/g。体外抗氧化试验结果显示,葡萄皮渣原花青素对DPPH自由基的半抑制质量浓度IC50为0.130 mg/mL,对羟基自由基的半抑制质量浓度IC50为0.228 mg/mL,与维生素C相比,其抗氧化能力更强。     

复合酶法提取长白木根总黄酮工艺优化及抗氧化活性研究

研究纤维素酶/果胶酶复合酶法提取长白楤木根中总黄酮的最佳工艺条件。以总黄酮得率为考察指标,通过Box-Behnken设计-响应面法,优化长白楤木根中总黄酮的提取工艺。结果表明,复合酶法提取长白楤木根总黄酮的最佳工艺为:复合酶添加量(质量分数为5%,纤维素酶:果胶酶=1:1)、提取时间为50 min、液料比为40:1 (mL/g)、乙醇体积分数为50%。在此条件下长白楤木根总黄酮的提取量达到最大值为8.6±0.05 mg/g。当长白楤木根总黄酮浓度为0.15 mg/mL时,对DPPH·、羟基自由基(·OH)、超氧阴离子自由基(O₂-·)清除能力较好,自由基清除率分别为96.3%、70.1%、44.1%,且清除自由基的能力比V_C更高。本研究得出了纤维素酶果胶酶复合酶法提取长白楤木根中总黄酮的最佳工艺条件,且提取出的长白楤木根总黄酮具有较强的体外抗氧化能力。     

响应面优化酶法提取虎斑乌贼肌肉多糖的工艺及抗氧化活性测定

研究胰蛋白酶提取虎斑乌贼肌肉多糖的工艺及体外抗氧化活性,并与水提法和碱提法的多糖进行比较。在单因素试验基础上以响应面法优化酶法提取多糖的工艺,结果显示最佳工艺条件为:酶解温度55℃、料液比1∶40(g/mL)、酶解时间4 h、加酶量2.5%,此时虎斑乌贼肌肉多糖得率为4.15%,优于水提法和碱提法的多糖得率。体外抗氧化活性研究表明酶法提取的多糖比碱提和水提的多糖具有更好的抗氧化活性,当多糖质量浓度为4 mg/mL时,水提、碱提和酶提虎斑乌贼肌肉多糖对·OH的清除率分别为50.15%、55.14%和89.47%,其IC50值分别为4.51、3.56 mg/mL和0.82 mg/mL;对DPPH自由基的清除率分别为28.89%、31.48%和40.80%,其IC50值分别为16.66、15.43 mg/mL和11.50 mg/mL;对O2-·的清除率分别为75.43%、81.63%和97.00%,其IC50值分别为1.15、0.69 mg/mL和0.29 mg/mL;还原力大小分别为0.134、0.156和0.193。综合分析表明,酶提法得到的多糖得率较高且具有较好的体外抗氧化活性。     

复合酶法提取长白楤木根总黄酮工艺优化及抗氧化活性研究

研究纤维素酶/果胶酶复合酶法提取长白楤木根中总黄酮的最佳工艺条件。以总黄酮得率为考察指标,通过Box-Behnken设计-响应面法,优化长白楤木根中总黄酮的提取工艺。结果表明,复合酶法提取长白楤木根总黄酮的最佳工艺为:复合酶添加量(质量分数为5%,纤维素酶∶果胶酶=1∶1)、提取时间为50 min、液料比为40∶1 (mL/g)、乙醇体积分数为50%。在此条件下长白楤木根总黄酮的提取量达到最大值为8.6±0.05 mg/g。当长白楤木根总黄酮浓度为0.15 mg/mL时,对DPPH·、羟基自由基(·OH)、超氧阴离子自由基(O~-_2·)清除能力较好,自由基清除率分别为96.3%、70.1%、44.1%,且清除自由基的能力比V_C更高。本研究得出了纤维素酶果胶酶复合酶法提取长白楤木根中总黄酮的最佳工艺条件,且提取出的长白楤木根总黄酮具有较强的体外抗氧化能力。     

酶法提取地桃花多糖的工艺优化及其抗氧化活性

目的:研究纤维素酶提取地桃花多糖的最佳条件,并探讨其体外抗氧化活性。方法:以地桃花多糖得率为响应值,在单因素试验基础上,以液料比、酶解温度、酶解时间、酶添加量为试验因素,采用响应面法建立数学模型,筛选最佳提取工艺条件;并使用DPPH和·OH自由基清除能力体系检测地桃花多糖的抗氧化活性。结果:纤维素酶酶解提取地桃花多糖最佳条件为:酶添加量10.8 mg/mL、酶解时间72 min、液料比7:1 mL/g、酶解温度43℃、pH为5.0,在此条件下地桃花多糖得率为13.32%,与理论值13.37%相对误差小于5%。地桃花多糖具有较强的抗氧活性,对DPPH和·OH自由基清除的半数抑制浓度IC₅₀分别为1.082、3.202 mg/mL,但与维生素C比较,抗氧化活性较弱。结论:通过响应面法获得地桃花多糖纤维素酶酶法提取的最佳条件,该工艺条件方便可行,提取到的多糖具有较强的自由基清除能力。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press