地被竹与淡竹叶提取物抗氧化活性的比较研究

以5种地被竹与淡竹叶为材料,采用Folin试剂还原比色法、硝酸铝-亚硝酸钠比色法和DPPH法、ABTS法、FRAP法、Fenton反应法比较其提取物中总酚、总黄酮含量及其抗氧化能力。结果表明,6种竹叶均含有很高的次生代谢物,其中鹅毛竹叶提取物的提取率最高,为8.70%±0.02%,高于淡竹的提取率(8.02%±0.06%);以干基计算,六种竹子总酚含量在4.13%~9.06%之间,总黄酮含量在2.35%~4.37%之间,其中两者含量最高的为鹅毛竹;竹叶提取物具有较强清除自由基的作用,清除DPPH自由基和ABTS自由基能力强于淡竹的有鹅毛竹和南平倭竹;不同竹种提取物的铁还原能力之间存在显著性差异,强于淡竹的只有鹅毛竹,其FRAP值为585.00μg/m L。     

水果中还原型和氧化型维生素C的分析

1 引言水果中维生素C是以氧化型和还原型两种都具生理活性的形式存在。但一般被认为:水果中还原型准生素C不仅占总维生素C的比例大,且其稳定性也能反映出总维生素C的稳定性,加之还原型维生素C的分析方法简单、快速,因此我国目前在研究水果中维生素C含量及其稳定性时,往往只测定还原型维生素C。事实上,水果在加工和贮存期间,不仅还原型维生素C可逆地转化为氧化型维生素C,而且一些水果如香焦,苹果中氧化型维生素C本身所占总维生素C的比例也很大,所以,水果中氧化型维生素C是总维生素C中不可忽视的重要部分。     

竹叶作为酿酒辅料对白酒的品质影响研究

为开发利用宜宾丰富的竹资源，探究竹叶作为酿酒辅料的可行性，将宜宾市当地3种竹种苦竹、慈竹、绵竹的竹叶分别以不同比例与糠壳混合酿酒，测定其对出酒率、酒的总酸、总酯、多酚、挥发性风味物质含量的影响。结果表明，3种竹叶分别替代糠壳时，出酒率仍能维持在30%以上；竹叶添加量为25%～75%、50%～100%时，酒中的总酸、总酯含量按从高到低排序为添加绵竹叶>添加慈竹叶>添加苦竹叶。添加苦竹叶或50%及以上的绵竹叶，可使酒中的多酚、挥发性酚类物质含量增多。感官分析发现，3种竹叶替代糠壳时，酒体均口感醇厚，谐调爽净，有淡竹香。3种竹叶作为酿酒辅料均有一定应用潜质，其中绵竹叶可使酒中的总酸、总酯含量显著增多（P<0.05），苦竹叶可使白酒中的多酚物质含量显著增多（P<0.05）。因此建议白酒实际生产中可用绵竹叶和苦竹叶替代糠壳。     

臭氧水处理对蔬菜中维生素C和胡萝卜素含量的影响

用臭氧水处理菠菜、小白菜、黄瓜三种蔬菜,测定不同处理时间各蔬菜中维生素C(VC)和胡萝卜素的含量,结果表明：随着处理时间的延长,蔬菜中还原型VC的含量明显下降,但总VC的含量维持不变;胡萝卜素的含量随着处理时间的延长,都有明显的下降。     

本底校正褪色光度法测定食品中还原型维生素C

还原型维生素C能将Fe3+定量还原 ,通过测定反应中所消耗的Fe3+量 ,即可间接测定样品中还原型维生素C含量。利用KSCN和罗丹明B能与Fe3+形成离子型缔合物的特性和表面活性剂吐温 80 (Tween 80 )的胶束增溶作用 ,使还原型维生素C的测定灵敏度显著提高。利用Cu2 +能将样品中还原型维生素C选择性氧化的特性 ,通过对食品样品的Cu2 +预氧化处理 ,实现对有色样品本底吸收的快速校正 ,建立了一种本底校正褪色光度法测定食品中还原型维生素C的新方法。应用本文方法测定了多种食品样品中还原型维生素C的含量 ,取得了满意的结果     

不同溶剂对竹叶提取物抑菌作用的影响

比较不同溶剂提取方法对淡竹和箬竹抑菌能力的影响,采用抑菌圈法测定淡竹和箬竹不同溶剂提取物对5种供试菌的抑菌作用。结果表明,淡竹、箬竹水提取物对白色假丝酵母菌、酿酒酵母菌、大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌有抑制作用,抑制作用效果不明显;淡竹、箬竹丙酮提取物对5种供试菌均表现抑制作用,淡竹丙酮提取物抑制效果为枯草芽孢杆菌>大肠杆菌>金黄色葡萄球菌=酿酒酵母菌>白色假丝酵母菌,箬竹抑菌效果是大肠杆菌>枯草芽孢杆菌>白色假丝酵母菌>金黄色葡萄球菌>酿酒酵母菌;淡竹、箬竹乙酸乙酯提取物对5种供试菌均表现出较强的抑菌作用,淡竹乙酸乙酯提取物平均抑菌圈直径为23.7mm,箬竹平均抑菌圈直径为22.8mm。两种竹叶水提取物抑菌效果较差,丙酮、乙酸乙酯能比较有效地从竹叶中提取具有抑菌活性的化学物质,其中乙酸乙酯的提取物抑菌效果最好,说明溶剂影响竹子提取物的抑菌能力。     

竹叶黄酮复方片的降脂实验研究

目的研究以竹叶黄酮为主,与决明子、柚子汁等不同成分优化组合,制备具有抗氧化活性和降脂功能的竹叶黄酮复方产品。方法建立高脂血症大鼠模型,根据总胆固醇水平随机分组,口服灌胃。实验组分别给予相应剂量的竹叶黄酮复方片（复方Ⅰ：竹叶黄酮、决明子、柚子汁和维生素C棕榈酸酯复配;复方Ⅱ：竹叶黄酮、决明子和柚子汁复配）和竹叶黄酮单方片,对照组灌胃相同体积的蒸馏水。实验结束后检测实验大鼠的血清总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）水平和血清总抗氧化活性、超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GSH-Px）活性及肝脏丙二醛（MDA）水平。结果药物干预6周后,竹叶黄酮复方Ⅰ可显著降低高脂血症大鼠血清的TC、TG、LDL—C水平,显著改善大鼠肝脏的脂肪沉积和变性状况;与高脂模型组比,竹叶黄酮复方Ⅰ和Ⅱ的血清总抗氧化能力、血清SOD活性均显著升高、优于竹叶黄酮单方实验组;此外,竹叶黄酮复方Ⅰ降低实验大鼠肝脏MDA水平的作用极显著（P〈0．01）,竹叶黄酮复方Ⅱ作用显著（P〈0．05）。结论竹叶黄酮与决明子和柚子汁复配,并添加维生素C棕榈酸酯后降脂协同增效作用显著,生物利用度提高,降低血脂和预防动脉粥样硬化的功效突出。     

辣椒粉中还原型维生素C含量的测定

采用钼蓝比色法测定辣椒粉中还原型维生素C含量,重点探究钼蓝化合物的最佳吸收波长、草酸-EDTA溶液中的EDTA-2Na最佳加入量以及水浴处理后的静置时间对检测结果的影响。结果表明:采用钼蓝比色法测量辣椒粉中还原型维生素C的含量,钼蓝化合物的最佳吸收波长为760nm,EDTA-2Na推荐加入量为0.075g/L,且水浴处理后无需静置。优化后的测定方法得到的维生素C标准曲线R2为0.97,还原型维生素C在0~0.04mg/mL内呈现良好的线性关系。该方法简便、快速、准确,适合批量和少量样品的测定。用此法测得的辣椒粉中还原型维生素C含量为4.12mg/g。     

不同基因型树莓营养成分比较的研究

比较了不同基因型树莓中游离氨基酸、无机元素等营养成分含量.结果表明:9个不同基因型树莓中均含有17种氨基酸,其中延K1树莓必需氨基酸含量和氨基酸总量含量均最高,无刺黑大量元素总量含量最高,菲尔都德红微量元素总量含量最高,不同基因型树莓中维生素C含量差异显著,顺K2含量最高,双季红的可溶性总糖含量最高为9.04%,顺K2总酸含量最低为7.60%.各基因型中重金属镉均未检出.     

褐变抑制剂对鲜切茄子保鲜的影响

为研究褐变抑制剂对鲜切茄子的保鲜效果,分别采用纯净水、0.5%食盐、0.5%柠檬酸、0.5%异抗坏血酸钠和0.5%植酸溶液浸泡处理5min后取出沥干,装在塑料托盘中并用聚乙烯保鲜膜包裹后冷藏（5℃）10d。每2d测定鲜切茄子的色泽、还原型抗坏血酸含量、失重率和总酸含量。结果表明：0.5%食盐溶液处理对鲜切茄子的褐变有一定抑制作用,0.5%异抗坏血酸钠溶液处理可以显著提高鲜切茄子的维生素C含量,0.5%柠檬酸和0.5%植酸溶液处理增加鲜切茄子的总酸含量,各种处理对鲜切茄子的失重没有影响。     

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