不同低温贮藏方式下贡柑的非靶标代谢组学研究

目的 探究不同低温贮藏方式下贡柑的非靶标代谢组学变化。方法 利用超高效液相色谱-质谱法(ultra performance liquid chromatography-mass spectrometry, UPLC-MS)对不同低温(-80、-20和4℃)贮藏处理的贡柑样品进行非靶标代谢组学分析,筛选贡柑果皮和果肉中的差异代谢物。结果 借助UPLC-MS技术的正离子模式和负离子模式,可分别实现贡柑中617种和483种代谢物的分析。贡柑非靶标代谢组学分析表明,经不同低温贮藏处理的贡柑组别之间均具有多种上调或下调的差异代谢物,并筛选获得贡柑果皮(或果肉)中的共有差异代谢物。贡柑中差异代谢物涉及到与柑橘水果中多糖类、黄酮类、生物碱类、多酚类等组分的代谢通路。结论 低温贮藏下贡柑的非靶标代谢组学研究,为贡柑的低温保鲜及其组分代谢研究奠定了基础。     

天然复合保鲜剂对麻竹笋贮藏品质的影响

为探究天然复合保鲜剂对麻竹笋贮藏保鲜的影响,以麻竹笋为原料,对8种天然保鲜剂进行筛选和复配得到一种天然复合保鲜剂,然后用天然复合保鲜剂处理新鲜麻竹笋,考察麻竹笋在贮藏期间的品质变化。结果表明,质量分数为1. 5%壳聚糖+0. 05%纳他霉素+1. 5%茶多酚可作为一种有效的天然复合保鲜剂,与空白对照组相比,天然复合保鲜剂可将麻竹笋的贮藏期限延长至36 d左右。天然复合保鲜剂处理组的麻竹笋在贮藏期间呼吸强度一直呈下降趋势,且始终低于实验对照组(1. 5%壳聚糖处理组)。与空白对照组相比,贮藏期间实验对照组和天然复合保鲜剂组的麻竹笋苯丙氨酸解氨酶和过氧化物酶活性较低,并呈现出先上升后下降的趋势,酶活性峰值出现的时间延后至27 d。天然复合保鲜剂处理的麻竹笋在贮藏期间木质素含量最少,增加程度最小,在贮藏后期硬度下降、质地变软,仍具有良好的感官品质。同时,天然复合保鲜剂能延缓麻竹笋中Vc的降解,贮藏期间最大程度地保留了麻竹笋的营养成分。     

热烫处理对麻竹笋质构特性的影响

以大叶麻竹笋为实验原料,研究了热烫处理对麻竹笋的质构特性的影响,同时分析了麻竹笋各质构参数间的相关性。结果表明:热烫处理使麻竹笋的硬度、凝聚性、弹性、咀嚼性和回复性等质构特性显著下降,但热烫10 min以后对麻竹笋的质构特性的下降不再显著;同时相关性分析表明麻竹笋的硬度、弹性、凝聚性、咀嚼性和回复性均能很好反映麻竹笋的质地变化。     

麻竹笋罐头贮藏过程中质构、果胶和色泽的变化

以麻竹笋为实验原料,研究麻竹笋罐头在常温（25 ℃）和低温（4 ℃）贮藏过程中质构、果胶和色泽的变化,并探讨麻竹笋罐头的硬度与果胶变化的相关性。结果表明：麻竹笋罐头在贮藏过程中硬度、原果胶和水溶性果胶含量逐渐下降,贮藏120 d后,常温贮藏和低温贮藏条件下麻竹笋的硬度分别下降39.5%和27.1%,原果胶含量分别下降66.4%和62.8%,水溶性果胶含量分别下降68.1%和75.7%。各果胶组分与硬度之间呈现较好的相关性,而原果胶与硬度之间的相关性高于水溶性果胶与硬度之间的相关性。麻竹笋罐头贮藏过程中亮度值L*和红绿值a*逐渐减小,黄蓝值b*逐渐增加;常温和低温分别贮藏30 d和70 d时,总色差ΔE＞2。     

基于代谢组学技术的玛咖产地鉴别

采用代谢组学的方法,基于超高效液相色谱-四极杆串联飞行时间质谱对不同产地的玛咖进行产地鉴别和各产地代谢物差异分析。通过正交偏最小二乘判别分析成功区分玛咖的5 个产地,并对各个产地玛咖的代谢物进行靶标和非靶标代谢组学分析,其中靶标代谢组学分析共鉴定出28 种代谢物,包括玛咖酰胺、玛咖烯、芥子油苷、生物碱、甾醇、多酚和黄酮,非靶标代谢组学分析鉴定出玛咖的产地标志物。结果表明代谢组学方法可以用于玛咖产地鉴别以及全组分的鉴定。     

腌制加工对麻竹笋质构和微观结构及色泽的影响

为了评价腌制加工对麻竹笋食用品质的影响,以大叶麻竹笋为实验原料,研究麻竹笋的质构、微观结构和色泽等在腌制加工前后的变化,并比较不同腌制食盐质量浓度之间的差异。结果表明：腌制加工以后麻竹笋的硬度、凝聚性、咀嚼性等质构特性显著下降,不同腌制食盐质量浓度对硬度有显著影响,而对凝聚性和咀嚼性的影响不显著。通过扫描电镜观察发现,麻竹笋在腌制加工以后,细胞壁呈现出明显的皱缩,细胞间隙增大,部分薄壁组织细胞出现破损。与鲜样相比,腌制加工后麻竹笋的亮度L*降低,黄色度b*升高,总色差ΔE＞2,说明腌制加工前后麻竹笋的色泽变化差异较大,可以从视觉上比较容易分辨。     

褪黑素和短波紫外联合处理对鲜切麻竹笋挥发性化合物的影响

摘要：目的：褪黑素和紫外照射(ultraviolet C, UV-C)处理能有效抑制鲜切麻竹笋褐变、腐烂等品质劣变现象。本研究拟进一步探究两种处理方式对麻竹笋香气的影响。方法: 利用气相色谱离子迁移谱联用技术(gas chromatography-ion migration spectrometry, GC-IMS)对麻竹笋挥发性香气进行分析。结果：GC-IMS检测结果结合表明麻竹笋挥发性成分以醇、醛和酯为主。鲜切麻竹笋中鉴定出70种挥发性化合物,包括18种醇、9种醛、4种酮、9种烯烃、10种酯、3种酸和7种其他挥发性化合物。紫外照射和褪黑素处理显著抑制鲜切笋发酵过程并且改变挥发性酯的种类和含量,导致2-甲基丁酸乙酯、乙酸乙酯、醋酸甲酯、丁酸丙酯明显积累。与单独紫外照射或褪黑素处理不同,联合处理可以提高反式2-丁烯乙酯、2-辛醇、3-甲基戊醇、丙酸含量,并抑制发酵过程中不良风味如对甲酚的积累。3-甲基吲哚、安息香醛、对甲酚、反式-2-庚烯醛可以作为判别不同处理贮藏麻竹笋的主要特征性标志物。结论：本文初步探究了褪黑素联合紫外处理对鲜切麻竹笋风味物质的影响,为鲜切麻竹笋保鲜提供理论支撑。     

红树莓和黄树莓果实中的代谢物比较分析

为探究黄树莓和红树莓成熟果实中的代谢物差异，对其进行非靶向LC-MS代谢组学分析。在正离子模式下，共检测到708种(98种已知)差异代谢物。在负离子模式下，共有780个(45种已知)差异代谢物。通过KEGG数据库的代谢富集分析，红树莓和黄树莓果实中共有1 566个差异代谢物质富集在新陈代谢、遗传信息处理、环境信息处理和人类疾病这4大类别上。这些差异代谢物质共富集在66个通路上，代谢途径富集的差异代谢物最多(34种)。此外，黄树莓果实中的飞燕草素葡萄糖苷、脱落酸、氢化肉桂酸和橙皮素较红树莓果实中分别下调了-1.496，-1.632，-1.527，-0.477倍。而原叶绿酸在黄树莓果实中上调了10倍以上。研究结果为不同树莓果实中特定化合物的开发和利用提供理论依据。     

基于UPLC-QE-Orbitrap-MS的宁夏枸杞鲜果和枸杞干果差异性代谢物分析

为研究不同宁夏枸杞果实的差异性，以枸杞鲜果和枸杞干果为样品，利用非靶向代谢组学方法分析枸杞鲜果和枸杞干果的差异性代谢物。采用超高效液相色谱-四极杆/静电场轨道阱高分辨质谱法建立非靶向代谢组学方法，通过主成分分析（PCA）、偏最小二乘法分析（PLS-DA）模型、单变量统计分析、聚类分析、火山图等统计学方法对所有代谢物进行鉴定分析，筛选出差异性代谢物。结果表明，枸杞鲜果和枸杞干果可以明显区分，枸杞鲜果和干果中共鉴定出35种差异代谢物，其中有机酸、氨基酸、黄酮类化合物呈上调表达，核苷酸类、酚酸类、香豆素类化合物呈下调表达。本研究基于非靶向代谢组学揭示了宁夏枸杞鲜果和枸杞干果的代谢产物差异性以及特征化合物，为研究不同枸杞果实的物质基础提供理论依据。     

基于非靶向代谢组学分析黄桃果肉褐变过程中代谢产物的差异

以黄桃果实为试验材料,利用非靶向代谢组学研究其贮藏期间不同褐变程度果肉中的代谢物差异。采用主成分分析、聚类分析、正交偏最小二乘判别分析等方法分析不同褐变程度果肉中的差异代谢产物。结果表明:PE包装明显降低了黄桃果肉褐变指数,以无褐变的果肉为对照,共检出991种代谢物。在CK 12 d vs CK 0 d样本中,共检出206种显著上调代谢物和26种显著下调代谢物,而在PE 12 d vs CK 0 d样本中,共检出145种显著上调代谢物和58种显著下调代谢物。经HMDB通路分析,代谢物主要富集在13条通路中,其中,富集排名前6的通路分别是丙烷和聚酮化合物、脂质和类脂质分子、有机杂环化合物、有机酸及其衍生物、苯甲酸酯类、有机氧化合物。KEGG通路分析表明,代谢物主要富集在10条通路中,其中,富集排名前4的通路为其它次生代谢产物的生物合成、氨基酸代谢、辅因子和维生素的代谢通路,其它氨基酸代谢等通路。研究从代谢组学角度初步揭示了黄桃果肉褐变过程中代谢产物的差异性,为提高黄桃果实品质提供理论参考。     

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