回心草总黄酮清除羟基自由基活性研究

以回心草为原料,以60%的乙醇水溶液为提取剂,得到回心草提取液,其中回心草总黄酮提取率为0.166%。向Fenton反应体系中加入回心草提取液,可以有效地清除体系中的羟基自由基（.OH）。清除.OH的效果随着提取液加入量的增加而增大,当总黄酮浓度19.89μg/mL时,清除效果最佳达68.00%。     

响应曲面法优化微波辅助提取人参须根粉中人参皂苷Rg5的工艺研究

为直接提取制备人参须根粉中的人参皂苷Rg5,实现一步法直接制备人参皂苷Rg5,以解决提取时间长、得率低的问题。在单因素实验基础上,采用响应曲面法优化微波辅助提取制备人参皂苷Rg5的工艺。研究了提取功率、提取液酸浓度、固液比和提取时间4个因素及其相互作用对人参皂苷Rg5得率的影响。利用高效液相色谱法对人参皂苷Rg5进行定量分析。实验结果表明,对人参皂苷Rg5得率的影响次序为提取液酸浓度>提取功率>固液比>提取时间;人参皂苷Rg5的最佳提取工艺条件为:提取功率500 W,提取液酸浓度0.12 mol·L-1,固液比1∶42（g·m L-1）,提取时间9 min,人参皂苷Rg5得率可达到3.14%,表明该方法可有效提取人参须根粉中人参皂苷Rg5。      

地木耳提取以自由基清除能力的初探

以地木耳为原料,分别以水、70%乙醇、丙酮为溶荆进行提取.通过对不同提取液还原能力、清除羟自由基(·OH)能力、清除超氧阴离子(O2-·)自由基能力及清除过氧化氢(H2O2)能力的测定,来初步研究了地木耳的抗氧化性.结果表明.不同提取液对·OH、O2-·及H2O2 都具有较强清除作用,并且与加入量相关.通过比较得出,地木耳水提取液对三种自由基的清除作用均强于乙醇提取液和丙酮提取液.     

人参花蕾在碳酸饮料中的应用

探索人参花蕾采收、处理、储藏、提取液制备条件并以参花蕾为原料研制碳酸饮料,通过色谱分析确定人参花蕾提取液制备条件为:乙醇浓度65%,浸泡时间2h;通过正交试验确定了影响口感和风味主要因素的最佳配方为:蜂蜜2%,可乐型香精0.08%,乙基麦芽酚12%.结果表明:对于人参花蕾的微苦的1:2味和独特的气味及营养价值得到保持和改良.所制饮料风味独特、口感甜润爽快且营养丰富.     

人参发酵菌种的筛选及皂苷转化能力研究

以人参皂苷Rb₁、Rg₃转化情况为指标,从78株植物乳杆菌中筛选具有人参皂苷转化能力的菌株。考察优选菌株在人参提取液中的发酵特性以及多种皂苷转化情况,采用人结直肠肿瘤细胞模型考察菌株发酵液的抗肿瘤作用。结果显示,78株菌株中植物乳杆菌581表现最优,Rb₁转化率达到75.41%,Rg₃提高倍数达13.59。经581菌株发酵的人参提取液风味有所改善,在发酵16 h后,pH为3.64,活菌数为2.1×10⁸ CFU/mL。与人参提取液相比,发酵液中皂苷Rb₁、Rb₂、Rc、Rd、Re、Rg₁的含量显著降低(P<0.01),5种稀有皂苷(Rg₃、Rk₃、F₂、C-K、Rg₆)的含量则显著升高(P<0.01)。581菌株人参发酵液对肿瘤细胞的存活抑制率为(59.16±1.26)%,显著高于未发酵前的人参提取液(P<0...     

新型C18核壳结构色谱柱快速分析人参中的 3种皂苷

目的建立高效液相色谱法(high performance liquid chromatography,HPLC)测定人参中人参皂苷Rg_1、Re和Rb_1 3种人参皂苷的含量。方法采用月旭Boltimate~(TM)C_(18)新型核壳色谱柱对3种人参皂苷进行分离,以乙腈-1.0%磷酸水溶液为流动相进行梯度洗脱,采用HPLC进行检测。结果 3种人参皂苷在月旭Boltimate~(TM)C_(18)新型核壳色谱柱能够快速分离,且分离效果较好。3种人参皂苷的在0.4~4.0μg质量浓度范围内呈良好的线性关系,线性相关系数(R~2)分别为0.9998,0.9996和0.9997;Rg_1、Re和Rb_1检出限分别为0.003、0.001和0.002μg/kg;加标回收率为98.3%~101.3%,相对标准偏差RSD分别为0.8%、1.1%和1.5%(n=6)。结论本方法具有快速、柱压低及节省溶剂等优势,可用于人参提取物中人参皂苷的测定。     

地木耳提取液对自由基清除能力的初探

以地木耳为原料,分别以水、70%乙醇、丙酮为溶剂进行提取。通过对不同提取液还原能力、清除羟自由基（·OH）能力、清除超氧阴离子（O2-·）自由基能力及清除过氧化氢（H2O2）能力的测定,来初步研究了地木耳的抗氧化性。结果表明,不同提取液对·OH、O2-·及H2O2都具有较强清除作用,并且与加入量相关。通过比较得出,地木耳水提取液对三种自由基的清除作用均强于乙醇提取液和丙酮提取液。      

乳酸菌发酵转化人参皂苷

筛选适合发酵转化人参皂苷的乳酸菌,并对发酵工艺进行优化,探讨人参提取物发酵过程中人参皂苷的生物转化路径。结果显示:植物乳杆菌转化人参皂苷的效果最好,得到的稀有皂苷含量相对较高;发酵工艺为:发酵温度35℃、发酵时间16 d、初始p H 6.0、底物浓度10%、接种量10%;得到的发酵液中稀有皂苷的含量可达到106.52μg/m L(F2)、74.62μg/m L(Rg3)和100.56μg/m L(CK),较发酵前分别提高188.13%、203.21%和395.86%。人参皂苷的可能转化路径与发酵过程中6种常见皂苷含量的变化是一致的。研究结果表明:植物乳杆菌发酵人参提取物过程中常见皂苷向稀有皂苷转化,通过发酵工艺优化使得稀有皂苷含量显著提高,得到的发酵产物用于人参产品的开发具有一定的优势,为人参品的深加工奠定基础。     

液相色谱-四级杆-飞行时间质谱检测人参奶粉中的皂苷类成分

人参山羊奶粉是一种由人参超微粉与奶粉混合而成的乳制品,生产过程中常需要精确控制其中的皂苷成分。本文建立了一种人参奶粉中皂苷类成分的提取分离方法,并结合液相色谱-四级杆-飞行时间质谱(LC-Q-TOF-MS)技术对其中的皂苷单体成分进行了鉴定和定量分析。该提取方法回收率(101.1%~105.3%)和精密度(1.28%)高,稳定性好。通过二级质谱碎裂技术鉴定了奶粉中20种皂苷单体成分,并定量测定了Rg1,Re,Rb1,Rb2,Rc,Rd六种皂苷单体含量。干法制备的奶粉中总皂苷含量(3.44±0.51 mg/g)高于湿法制备获得的人参奶粉(2.38±0.14mg/g)。皂苷单体的测定结果与总皂苷一致,两种奶粉中皂苷单体的测定结果为:Rg1(11.22±3.1μg/g v.s. 8.03±2.9μg/g),Re (22.99±5.5μg/g v.s. 18.91±0.38μg/g),Rb1(7.43±0.41μg/g v.s. 4.83±0.14μg/g),Rb2(65.29±5.32μg/g v.s. 58.21±3.15μg/g),Rc(11.64±1.02μg/g v.s. 8.80±0.92μg/g),Rd(10.09±0.69μg/g v.s.7.81±0.52μg/g)。湿法制备得到的人参奶粉的均匀度较好,两种奶粉提取物中质谱检测未发现明显的皂苷降解峰。本方法可以为含有人参成分的食品分析检测和质量控制提供技术方案。     

高效液相色谱法测定人参保健酒中11种人参皂苷含量

该研究建立了高效液相色谱法(HPLC)同时测定人参保健酒中11种人参皂苷(人参皂苷Rg1、Re、Rf、Ra2、Rb1、Rc、Ra1、Ro、Rb2、Rb3、Rd)的方法。采用Agilent SB C₁₈色谱柱(4.6 mm×250 mm,5μm),以乙腈-0.1%磷酸为流动相梯度洗脱,流速1.0 m L/min,柱温28℃,人参皂苷的检测波长203 nm,进样量10μL的条件进行测定。结果表明,11种人参皂苷在各自浓度范围内线性关系良好(R2≥0.999 9),检出限在1.52～3.03 mg/L,定量限在4.59～9.18 mg/L,该方法精密度试验、稳定性试验、重复性试验结果相对标准偏差(RSD)均小于5%,平均加标回收率95.39%～101.96%,RSD为0.07%～2.46%。该方法操作简单,准确度高,重复性好,可用于人参保健酒中11种人参皂苷含量测定。     

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