油菜蜂花粉黄酮醇的测定及其抗氧化活性研究

本实验通过盐酸酸解蜂花粉乙醇提取物,薄层色谱法分离酸解液中黄酮醇,并测定酸解液中黄酮醇的含量及其抗氧化活性。结果表明：蜂花粉乙醇提取物酸解后,槲皮素(Rf 值0.59)含量为0.40mg/g,山奈酚(Rf 值0.71)含量为3.98mg/g,酸解液DPPH·清除率强于花粉乙醇提取物。经制备液相分离,采用核磁和质谱鉴定出一种酮醇苷,其结构为山奈酚3-O-(2＂-O- β-D- 吡喃葡萄糖)- β-D- 葡萄糖。采用TLC-DPPH 技术对蜂花粉乙醇提取物及其酸解液中抗氧化成分进行追踪,为花粉中黄酮醇苷的抗氧性研究提供参考。     

油菜蜂花粉中黄酮类化合物的提取工艺研究

本研究采用乙醇提出、水沉淀,并结合大孔树脂富集、乙醇洗脱等方法进行破壁油菜蜂花粉中黄酮类化合物的提取工艺研究,获得较好结果.花粉总黄酮的转移率可达70%以上,提取物的黄酮类化合物含量大于50%.采用柱式分离、有机溶剂分步洗脱等方法从提取物中分离出芦丁、槲皮素、山奈酚、异鼠李素等四种单体黄酮,经核磁共振结构鉴定证实的有芦丁、槲皮素、山奈酚等三种.同时,采用富集、洗脱等方法分离出β-谷甾醇、β-豆甾醇等两种生物活性物质并经核磁共振结构鉴定证实.     

油菜蜂花粉中黄酮的分离纯化及结构鉴定

研究油菜蜂花粉黄酮的组成,采用乙醇提取,石油醚萃取脱脂和柱层析分离方法对油菜蜂花粉黄酮进行研究,得3个黄酮类化合物,经1 H-NMR、13 C-NMR,分别鉴定出3个黄酮类化合物化学结构为山奈酚-3-O-β-D-吡喃葡萄糖苷、山奈酚-3-O-β-D吡喃葡萄糖基(1→2)-β-D-吡喃葡萄糖苷和槲皮素-3-O-β-D-吡喃葡萄糖苷,与HPLC-MS检测结果一致。     

油菜蜂花粉中黄酮类化合物的提取与鉴定

以湖北大宗油菜蜂花粉为材料,对其中微量特征成分黄酮类化合物进行鉴定。采用超声波辅助技术提取,运用二次回归正交旋转组合实验优化提取工艺,通过响应面分析和岭嵴寻优分析,确定黄酮类化合物的最佳提取条件;采用HPLC-DAD 以及HPLC-MS 对酸解后的提取液进行分析。结果表明：超声波辅助技术提取油菜蜂花粉中黄酮类化合物的最佳条件为体积分数76% 乙醇、料液比1:30、超声波时间33min,超声波温度为51℃。蜂花粉中总黄酮含量的理论得率为2.12%,实际得率为1.89%,实测得率达到理论预测值的89.15%。HPLC-DAD 以及HPLCMS分析结果证实油菜蜂花粉中可能含有9 种黄酮苷元。其中可以推定的黄酮类物质是槲皮素、山奈酚、异鼠李素和柚皮素。可为识别蜂花粉的植物来源,鉴别真伪提供研究方法和实验依据。     

破壁油菜蜂花粉的制备及其形态表征

为探索花粉细胞的新型破壁方法,利用脉冲电场技术制备破壁型油菜蜂花粉,并用光学显微镜和扫描电子显微镜等显微方法初步考察经脉冲电场破壁处理后蜂花粉细胞微形态的变化。结果表明,未处理的蜂花粉细胞形态完整,萌发孔呈闭合态;处理后的细胞萌发孔打开,细胞外壁脱落,细胞形状也发生显著变化。利用脉冲电场对油菜蜂花粉进行破壁处理时条件温和,耗时短,操作方便,破壁效果显著,这为油菜蜂花粉细胞的破壁提供一种新型而有效的途径。     

薄层层析-生物自显影法筛选油菜蜂花粉中活性成分

采用薄层层析- 生物自显影法筛选油菜蜂花粉中清除DPPH 自由基的活性成分和抑菌活性成分。结果显示：油菜蜂花粉中清除DPPH 自由基的黄酮类活性成分主要以苷的形式存在,酸解后生成了包括槲皮素和山奈酚在内的多种抗氧化成分;在Rf 值0.29 和0.86 处存在抑菌活性成分,不同显色方法确认,抑菌活性成分的种类可能包括酚类、鞣质、黄酮类或皂苷类。     

蜂花粉中黄酮类化合物的鉴定和含量测定

以24种不同蜂花粉为材料,对其中微量特征成分黄酮类化合物进行鉴定和归纳。建立一种高压液相色谱-串联三重四级杆质谱法快速测定蜂花粉中8种黄酮类化合物的方法。破壁的试样经乙醇溶液提取后加酸水解,经反相色谱分离,质谱定性并测定8种黄酮类化合物含量,外标法定量。该方法线性良好,R2均大于0.999,检出限为0.15~3.0 mg/kg,精密度为3.2%~6.6%,回收率在91.2%~100.2%,此方法操作简便,抗基质干扰、结果可靠。分析结果证实,蜂花粉中黄酮类化合物通常有槲皮素、山奈酚、芦丁等。可为识别蜂花粉的植物来源,鉴别真伪和建立相应的指纹图谱提供研究方法和实验依据。     

RP-HPLC测定小茴香中槲皮素和山奈酚含量

建立用反相高效液相色谱法同时测定小茴香中槲皮素和山奈酚含量的方法。采用Eclipse XDB-C18色谱柱(4.6 mm×150 mm,5μm);柱温:25℃;流动相:甲醇-0.4%磷酸(50∶50);流速:1mL/min;检测波长:360nm。槲皮素、山奈酚分别在2.19~109.6μg/mL和2.28~114.0μg/mL范围内线性关系良好。槲皮素和山奈酚的平均回收率分别为95.61%,94.41%,RSD分别为2.4%,3.0%。此方法简便、准确、可靠,可作为小茴香中槲皮素和山奈酚的定量分析方法。测定出小茴香总黄酮水解物中槲皮素和山奈酚的含量分别为:槲皮素0.29 mg/g,n=3,RSD=2.60%;山奈酚含量为:0.36mg/g,n=3,RSD=3.25%。     

HPLC法测定蜂蜜中槲皮素和山奈酚

目的建立同时测定蜂蜜中槲皮素和山奈酚含量的方法。方法以Hpersil BDS C18(250 mm×4.6 mm,5μm)为分析柱,流动相为甲醇 0.4%磷酸水溶液(45 55)并用三乙胺调节pH至4.2,流速为1.0 ml/min,检测波长为375 nm。结果槲皮素的线性范围为0.045-2.25μg,山奈酚的线性范围为0.052-2.600μg,相关系数均为0.999 1;平均回收率分别为95.9%,97.6%。5种蜂蜜中均含微量槲皮素(18.62-189.26μg/g)和山奈酚(5.97-22.54μg/g),其含量与蜜源有关,桉树蜜中槲皮素含量最高(189.26μg/g),红树林蜜中山奈酚含量最大(22.54μg/g)。结论该方法简便、准确,可以用于同时测定蜂蜜中槲皮素和山奈酚的含量。     

枸杞叶黄酮提取物的组成及初步结构表征

本文采用高温乙醇回流法得到一种枸杞叶黄酮提取物,经硝酸铝-亚硝酸钠比色法测定该提取物的总黄酮含量为347.00 mg/g。采用紫外-可见光谱(UV-Vis)和傅里叶变换红外光谱(FT-IR)对其进行初步结构表征,发现枸杞叶黄酮提取物的UV-Vis谱图中含有A-环苯甲酰和B-环肉桂酰系统的特征吸收峰,其FT-IR谱图也显示有C=C、羟基、酚羟基、甲氧基以及甲基等多种特征官能团的振动吸收峰,具有黄酮类化合物的典型结构。通过高效液相色谱(HPLC)测定枸杞叶黄酮提取物中各黄酮类化合物的组成与含量,得出该提取物含有芦丁、绿原酸、槲皮素、咖啡酸、对香豆酸、山奈酚6种黄酮类化合物,含量分别为100.74、0.31、23.59、42.83、2.94、0.08 mg/g,表明提取物是一种富含芦丁、绿原酸和槲皮素的天然黄酮类物质,在天然食品添加剂和功能食品原料等方面具有开发利用价值。     

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