采前套袋与未套袋处理对黄桃采后贮藏品质的影响

以黄桃为材料,研究采前套袋和未套袋处理对其采后贮藏期间果肉褐变指数、硬度、总糖、可溶性固形物(SSC)、可滴定酸(TA)、维生素C(VC)、总酚、总黄酮和多酚氧化酶(PPO)、过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性及总抗氧化能力的影响。结果:未套袋组黄桃果实的腐烂和褐变程度较套袋组轻,贮藏8 d时,腐烂率分别达90%(套袋组)和80%(未套袋组),褐变指数分别达78.3%(套袋)和67.5%(未套袋)。品质分析表明,采前未套袋处理延缓了黄桃果肉硬度、TA、总糖、SSC、总酚和总黄酮含量的降低。抗氧化分析表明,采前未套袋处理可保持PPO、POD、SOD和CAT活力,且在贮藏后期具有更高的抗氧化能力。相关性分析表明,腐烂率与抗氧化剂含量、抗氧化酶活力呈显著正相关(P0.05或P0.01),但分别与营养组分、总抗氧化活性呈高度负相关。抗氧化剂(VC,总酚和总黄酮)与抗氧化酶活性(PPO,POD和SOD)呈显著正相关(P0.05)。分层聚类分析将17种生理生化指标分为2大类,该聚类分析结果与主成分分析结果一致,可反映黄桃果实生理、生化指标间的相似与差异。结论:采前未套袋处理的黄桃果实贮藏品质优于采前套袋处理的黄桃果实。     

几种保鲜处理对贮藏期间‘红阳’猕猴桃抗氧化生理特性变化的影响

为了研究不同保鲜处理对‘红阳’猕猴桃果实采后抗氧化相关生理特性变化的影响,以‘红阳’猕猴桃为试材,分别用1-甲基环丙烯(1-MCP)、臭氧、气调和热激处理后于(4±1)℃,相对湿度90%~95%条件下贮藏,定期测定其维生素C(VC)、总酚、花色苷的含量以及DPPH·清除率、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活性,探讨不同保鲜处理对猕猴桃果实抗氧化活性的影响。结果表明:4种处理均能不同程度地抑制果实VC、花色苷含量的降低,延缓总酚、DPPH·清除率、SOD、POD和CAT峰值的出现,抑制其活性的下降;其中,臭氧(臭氧浓度200mg/m3,处理时间0.5h)处理‘红阳’猕猴桃果实效果最佳,能很好地保持果实的抗氧化活性,从而提高其贮藏期间的抗氧化能力。     

壳聚糖涂膜结合冰温贮藏对蓝莓活性成分及抗氧化活性的影响

以蓝莓为试材,研究冷藏、壳聚糖涂膜、冰温和壳聚糖涂膜结合冰温贮藏对蓝莓活性成分含量及抗氧化活性的影响。结果表明,与直接冷藏相比,壳聚糖涂膜、冰温以及壳聚糖涂膜结合冰温贮藏都能有效延缓蓝莓果实贮藏过程中总花色苷、VC、总酚和总黄酮含量的下降,蓝莓果实中总花色苷、总酚和总黄酮含量与1,1-二苯基-2-三硝基苯肼自由基清除能力之间均呈显著正相关,能更好地保持蓝莓的抗氧化活性。而壳聚糖涂膜结合冰温贮藏的效果优于单独采用冰温或壳聚糖涂膜贮藏。因此,壳聚糖涂膜结合冰温贮藏能较好地保持蓝莓活性成分含量及抗氧化活性,是一种较为有效的蓝莓贮藏方法。     

减压贮藏对番茄果实抗氧化物质和抗氧化酶的影响

为了研究不同减压处理对番茄果实后熟过程中抗氧化性的影响,以粉冠番茄为材料,研究了在43.6、73.0kPa和常压三个压力条件下,番茄中维生素C、番茄红素和谷胱甘肽含量,以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性变化规律。结果表明,减压贮藏显著推迟了番茄中维生素C含量的高峰,在一定程度上延迟了番茄红素和谷胱甘肽含量的高峰,并且压力越低效果越显著(p<0.05);在果实后熟过程中SOD、CAT活性逐渐下降,而减压处理可显著抑制SOD活性下降(p<0.05)。POD活性在贮藏期间呈现先降后升的趋势,减压处理可以有效地保持较高的抗氧化酶活性。结论:减压处理贮藏可以显著保护番茄果实中的抗氧化物质和抗氧化酶活性,而且一定范围内压力越低效果越好。      

减压贮藏对番茄果实抗氧化物质和抗氧化酶的影响

为了研究不同减压处理对番茄果实后熟过程中抗氧化性的影响,以粉冠番茄为材料,研究了在43.6、73.0kPa和常压三个压力条件下,番茄中维生素C、番茄红素和谷胱甘肽含量,以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性变化规律.结果表明,减压贮藏显著推迟了番茄中维生素C含量的高峰,在一定程度上延迟了番茄红素和谷胱甘肽含量的高峰,并且压力越低效果越显著(p＜0.05);在果实后熟过程中SOD、CAT活性逐渐下降,而减压处理可显著抑制SOD活性下降(p＜0.05).POD活性在贮藏期间呈现先降后升的趋势,减压处理可以有效地保持较高的抗氧化酶活性.结论:减压处理贮藏可以显著保护番茄果实中的抗氧化物质和抗氧化酶活性,而且一定范围内压力越低效果越好.     

肉桂精油处理对低温贮藏期间‘红阳’猕猴桃抗氧化活性的影响

为保持果实贮藏期间较高的抗氧化活性,以‘红阳’猕猴桃为试材,分别用不同体积分数(100、200、400和800μL/L)肉桂精油处理后置于(4±1)℃,相对湿度90%~95%条件下贮藏120 d,每20 d测定维生素C(Vc)、总酚、花色苷的含量,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活性及果肉总抗氧化能力、超氧阴离子自由基(O2-·)、羟自由基(·OH)、DPPH·清除能力,探讨肉桂精油处理对猕猴桃果实抗氧化活性的影响。结果表明:肉桂精油处理能有效抑制果实Vc、花色苷含量的降低,延缓总酚、SOD、POD、CAT、总抗氧化能力、O2-·、·OH、DPPH·清除率峰值的出现,抑制其相关酶活性的下降;其中,400μL/L肉桂精油处理‘红阳’猕猴桃果实效果最佳,能更有效地保持果实中具抗氧化活性能力物质,从而提高其贮藏期间抗氧化能力。     

几种保鲜处理对红阳猕猴桃活性氧代谢的影响

利用主成分分析方法探讨几种保鲜处理对红阳猕猴桃果实活性氧代谢的影响。结果表明:2种复合保鲜处理能更有效地抑制果实VC、花色苷含量的降低,推迟总酚、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)、超氧阴离子自由基(O-2·)、羟基自由基(·OH)、DPPH·清除率峰值的出现,抑制相关酶活性的降低,保持果实良好的抗氧化活性。经主成分分析结果表明,成分1和成分2可共同对贮藏至20 d和120 d果实进行有效区分,同时,2种复合处理对保持果实贮藏期间良好的抗氧化活性具有较好的作用,2种处理间差异不显著,基于成本及操作性综合考虑,首选精油与1-甲基环丙烯(1-MCP)复合作为最佳处理方式。     

机械损伤对富士苹果抗氧化酶活性的影响

研究富士苹果遭受机械损伤后在两种贮藏温度下伤害部位超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)等酶活性的变化,并对抗坏血酸(AsA)、还原性谷胱甘肽(GSH)等内源抗氧化剂的含量进行分析测定。试验结果表明:与对照果实相比,受伤果实的SOD活性、APX活性在贮藏初期逐渐下降,GR活性迅速下降后又上升,CAT活性、POD活性逐渐上升;同时,作为抗氧化剂GSH含量与AsA含量与GR活性保持了相同的变化趋势;随着贮藏时间的延长,各种抗氧化酶活性和抗氧化剂含量又呈现上升和下降的反复过程,而且温度越低,各种生理指标变化越缓慢,且显示较高的酶活性和较高的抗氧化剂含量。表明机械损伤显著地诱导了抗氧化酶活性和抗氧化剂含量的变化,以达到提高受伤组织自身对伤害的修复能力,而且在低温下,受伤部位具有较高的对伤胁迫的修复能力。     

1-MCP对梨果实脂膜过氧化影响的研究

以"爱甘水"梨果实为实验材料,研究了1-MCP处理对梨果实脂膜过氧化及其相关酶的影响,测定了经1-MCP处理后梨果实中乙烯释放量、丙二醛(MDA)含量,过氧化氢(H2O2)含量、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性、抗坏血酸过氧化物酶(APX)活性、多酚氧化酶(PPO)活性的变化,探讨了1-MCP对梨脂膜过氧化的影响。结果表明:1-MCP对梨果实采后贮藏过程中脂膜过氧化有一定抑制作用,抑制了MDA和H2O2含量的增加,对CAT活性、PPO活性、POD活性、APX活性有一定促进作用。1-MCP可以有效地延长果实的贮藏寿命,保持果实品质。     

微真空贮藏条件对莱阳梨果实膜脂过氧化的影响

为探讨微真空贮藏条件延缓果蔬采后衰老的生理机制,以莱阳梨为试验材料,在贮藏温度为3±1℃、真空压力为66 661～79 993.2Pa的微真空贮藏条件下,通过对莱阳梨果实中抗氧化酶CAT、SOD、POD活性及活性氧O2-.、H2O2摩尔质量浓度消长的变化、LOX活性与MDA摩尔质量浓度、膜透性的分析,结果表明:与相同温度下的常压贮藏相比,微真空贮藏能显著提高CAT、SOD、POD活性,降低LOX的活性及O2-.、H2O2摩尔质量浓度,延缓相对电导率和MDA摩尔质量浓度的增加(P≤0.05)。表明微真空贮藏条件可能通过上调莱阳梨果实中内源抗氧化酶活性和下调LOX活性,以减少活性氧的产生及对膜的损伤,降低膜脂过氧化程度,延缓梨果实的衰老进程。     

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