热带睡莲精油的超临界CO2萃取优化及其成分GC-MS分析

以热带睡莲精油得率为考察指标,通过单因素试验和正交试验对热带睡莲精油的超临界CO2萃取工艺进行优化。采用气相色谱-质谱联用技术(gas chromatgraphy-mass spectrometry,GC-MS)分析萃取精油中的挥发性组分。优化试验结果表明,超临界CO2萃取热带睡莲精油的最优工艺条件为:萃取压力27.5 MPa,萃取温度45℃,循环萃取时间120 min,此时的精油得率为1.92%。精油挥发性成分分析结果表明:从萃取所得的睡莲精油中共鉴定出42种挥发性成分,其中含量超过5%的优势成分有5种,这些成分包括6,9-十七碳二烯(含量为25.406%)、十五烷(含量为22.010%)、苄基醇(含量为11.011%)、8-十七碳烯(含量为9.916%)和金合欢烯(含量为8.601%)。     

同时蒸馏萃取制备延药睡莲精油及其抗氧化研究

以延药睡莲(Nymphaea stellata)花瓣为原料,采用同时蒸馏萃取法(simultaneous distillation extraction,SDE)从中提取精油,再通过气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)手段鉴定精油中的主要化学成分,并对精油的体外抗氧化性进行初步研究。结果表明,NaCl含量、蒸馏时间、料液比皆会影响延药睡莲精油的含量,最佳提取率为0.101%。延药睡莲精油主要成分为羰基类化合物如2-十七烷酮等;延药睡莲精油具有一定的体外抗氧化性,但是抗氧化性要比2,6-二叔丁基对甲酚(2,6-Di-tert-butyl-4-methylphenol,BHT)弱。     

4种热带睡莲营养成分对比分析

以热带睡莲为研究对象,分别对其花瓣和茎的含水量、灰分、蛋白质、粗脂肪、可溶性糖、维生素C、氨基酸种类和含量进行测定。结果显示,4种热带睡莲花瓣和茎段的含水量都很丰富,可溶性糖含量较高,尤其粉睡莲茎可溶性糖含量最高,达到345.97 mg/g,脂肪和蛋白质均有检测出,并含有一定量的维生素C和多种氨基酸,其中粉睡莲花瓣的总氨基酸含量高达193.86 mg/100 g,蓝睡莲花瓣中必需氨基酸含量高达45.07 mg/100 g,均为种理想的菜用睡莲。通过综合比较分析,热带睡莲花瓣和茎均有一定的食用价值,可以在市场上进行推广。     

菲律宾开发睡莲纤维

菲律宾研发部门对利用马尼拉麻纤维、菠萝和香蕉纤维作为热带织物的原料进行广泛的研究以及商业化推进之后,开始研究睡莲纤维。睡莲纤维适用于生产家用纺织品,如窗帘,椅垫,乒乓球网,餐巾和手工     

热空气结合肉桂精油熏蒸脆红李保鲜工艺优化

为确定热空气结合肉桂精油处理对脆红李果实保鲜的较优条件,以果实腐烂指数为考察目标,采用单因素试验对不同热空气结合肉桂精油处理时间、温度和肉桂精油浓度进行筛选,利用响应曲面法优化热空气结合肉桂精油熏蒸处理脆红李保鲜工艺,对比分析该条件下果实的贮藏品质。结果表明,热空气结合肉桂精油熏蒸处理保鲜脆红李的较优条件为:处理时间3.1 h、温度32.5℃、肉桂精油浓度188μL/L,测得脆红李果实的腐烂指数为16.37%。与对照组相比,该条件下还能显著提高脆红李贮藏期间果实硬度、总酸、VC含量,延缓可溶性固形物含量下降,研究结果为热空气结合肉桂精油熏蒸在脆红李保鲜的应用提供参考。     

饲料中添加牛至精油对红罗非鱼货架期的影响

研究牛至精油对红罗非鱼品质和货架期的影响。以空白添加组为对照,分别在对照组饲料中添加250、500、1 000、2 000 mg/kg牛至精油,经过20周养殖实验,红罗非鱼在4℃条件下冷藏0、7、14、21 d,在每个冷藏时间点检测红罗非鱼物理化学特性、微生物定性定量分析和感官分析评估,以判定其腐败程度。结果表明,牛至精油添加对红罗非鱼体色、硫代巴比妥酸反应值和总挥发性盐基氮含量有显著的影响。1 000、2 000 mg/kg牛至精油可有效降低冷藏鱼片的肠杆菌和大肠菌群数量。感官分析表明,红罗非鱼体的质量指数与牛至精油的添加量没有显著相关,对照组的货架期为16 d,牛至精油组的货架期为18 d,但与添加量无显著相关。     

三种花椒精油的化学成分及其抑菌作用对比研究

采用水蒸气蒸馏法提取汉源红花椒、江津青花椒、峨眉山藤椒果皮精油,经GC-MS分析3种精油的挥发性成分,并通过抑菌圈实验和96孔板二倍稀释法对其抑菌特性进行研究,结果表明:汉源红花椒、江津青花椒、峨眉山藤椒果皮精油相对含量在1%以上的组分分别有44种、34种、29种,芳樟醇含量均最高,分别为64.23%,21.60%,59.62%;经比较,红花椒果皮精油对细菌和真菌的抑菌效果最好,其中,金黄色葡萄球菌对红花椒精油最敏感(MIC值为0.31mg/mL)。     

三种花椒精油的提取研究

采用水蒸汽蒸馏法对重庆江津青花椒、江津红花椒和成都红花椒等三种花椒进行了精油的提取,得率分别为0.08918、0.04125、0.04426mL/g,结果表明,江津青花椒精油含量明显高于江津红花椒和成都红花椒。然后采用直接回流法和索氏提取法对江津青花椒进行了精油的提取,得率分别为14.43%,13.24%,再比较水蒸气蒸馏法提取花椒精油的实验得率7.43%,得出直接回流法提取的精油得率最高。     

E-Nose结合GC-MS分析两种花椒精油成分及其抑菌活性研究

对红花椒精油和青花椒精油进行风味成分分析和抑菌活性研究,利用电子鼻联合气质及抑菌实验,为花椒精油在食品行业的保鲜利用及研发新型食品抑菌复配剂提供了理论指导.通过GC-MS、电子鼻测定两种花椒精油的挥发性风味物质,并对其做出比较和分析;通过打孔法、滤纸片法、二倍稀释法分别测试两种花椒精油对大肠杆菌、金黄色葡萄球菌、枯草芽...     

广玉兰花精油的化学成分、抗氧化及抑菌活性分析

用乙醚为溶剂索氏提取广玉兰花精油。气相色谱-质谱联用仪(GC-MS)分离并分析鉴定广玉兰花精油成分及相对含量;鉴定出43个化合物,占精油总量的95.49%。DPPH自由基清除法测定精油的抗氧化活性;广玉兰精油有很强的清除DPPH自由基的能力,当质量浓度达到20μg/m L时,去除率与抗坏血酸相当。抑菌圈法和平板菌落生长法测定精油的抑菌抗菌活性;广玉兰花精油对细菌、真菌均有抑制作用,特别是对红酵母有强的抑制作用,当培养基中精油质量浓度为5.00 mg/m L时能完全抑制培养基中的红酵母生长。广玉兰花精油用于食品工业不仅可作香料还具有食品防腐保鲜效果,具有一定的开发和利用价值。     

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