1-MCP结合低温处理对丽江雪桃采后生理的影响

丽江雪桃外形美观、果型硕大,口感甜脆,营养丰富。1-MCP是一种新型的乙烯受体抑制剂,在果蔬保鲜中运用较为广泛。本文通过探讨1-甲基环丙烯(简称1-MCP)对丽江雪桃的保鲜效果及机理,寻找一种符合食品安全的丽江雪桃保鲜方法。以丽江市龙县拉市乡的丽江雪桃为试验材料,研究用0.5、1、1.5、2μL/L的1-MCP分别处理丽江雪桃后,放置在冷藏(3±1)℃条件下的生理变化情况。结果表明:在冷藏条件下,1-MCP处理丽江雪桃能够有效的保持丽江雪桃硬度和细胞膜透性,抑制丽江雪桃的呼吸作用,1、1.5、2μL/L的1-MCP处理丽江雪桃能增加丽江雪桃果肉POD的活性,1μL/L的1-MCP处理组的丽江雪桃可以抑制总酚含量和PPO活性的下降效,抑制丽江雪桃的果肉褐变,综合分析,1μL/L的1-MCP处理丽江雪桃的保鲜效果较好。     

1-MCP处理在低温条件下贮藏对丽江雪桃采后生理的影响

以丽江雪桃为试材,研究(3±1)℃贮藏条件下1-MCP(1-甲基环丙烯)结合保鲜膜处理对果实采后生理的影响。结果表明1-MCP处理可以减少丽江雪桃的采后失水,0.6μL/L1-MCP处理对保持丽江雪桃水分的效果较明显。1.8μL/L1-MCP结合保鲜膜包装处理可以推迟呼吸高峰的到来,推迟丽江雪桃POD酶的活性高峰,并且降低峰值。     

1-MCP结合减压贮藏对翠冠梨采后生理和品质的影响

目的:研究1-MCP结合减压贮藏保鲜翠冠梨的新技术. 方法:以常规冷藏为对照,研究1-MCP结合减压贮藏对翠冠梨采后生理、生化和主要品质指标的影响. 结果:1-MCP结合减压贮藏能够减少贮藏期果肉可溶性总糖、可滴定酸和VC的损失,保持果肉硬度和亮度,显著延缓翠冠梨贮藏期的品质劣变.1-MCP结合减压处理可显著减少乙烯释放量,抑制呼吸代谢,并能够有效保持超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的活性,延缓细胞膜透性的增大.经60d的贮藏后,对照果实硬度只有入贮时的48.7%,而处理果实硬度仍保持89.1%,具有清脆的口感及较好的甜度、香气等品质,未出现组织发绵、果肉褐变、后苦味等不良现象,保持了翠冠梨独特的商品价值. 结论:1-MCP结合减压处理在翠冠梨的采后保鲜方面具有非常好的应用前景.     

低温贮藏下不同1-MCP浓度对桃生理特性的影响

以"秋蜜红"桃为试材,在(0±1)℃贮藏温度条件下,研究了不同1-MCP浓度处理(0.5、1.0、1.5、2.0μL/L)对桃果实贮藏过程中果实硬度、细胞膜透性、可溶性固形物、呼吸强度、乙烯释放速度、丙二醛(MDA)、超氧化物歧化酶活性(SOD)、过氧化物酶活性(POD)和多酚氧化酶活性(PPO)的变化。研究发现:1.0、1.5、2.0μL/L浓度1-MCP处理能显著抑制桃果实软化,降低细胞膜透性、果实呼吸速率、乙烯释放速率、丙二醛含量和PPO活性,并推迟呼吸速率和乙烯释放率高峰;提高SOD和POD活性,对可溶性固形物含量变化并无显著差异;在贮藏过程中,0.5μL/L浓度1-MCP处理与对照组之间桃果实生理特性变化并无显著差异。综合考虑,1.0μL/L的1-MCP处理是一种经济、安全、有效的保鲜方法,在今后桃贮藏保鲜中具有极大的应用和推广价值。     

1-甲基环丙烯(1-MCP)对桃果实贮藏效果的影响

以“24号”桃果实为试材,研究1-甲基环丙烯(1-MCP)处理对该桃的贮藏效果的影响。试验结果表明:使用500nL/L浓度的1-MCP熏蒸处理的“24号”桃在5℃下贮藏28d,3d货架期(室温17℃)后的果肉褐变指数为31%;而在5℃冷藏的桃果肉褐变指数货架期后为62%。1-MCP处理能够显著地抑制“24号”桃在贮藏过程中的果肉褐变。     

1—甲基环丙烯（1—MCP）对枫果实贮藏效果的影响

以“24号”桃果实为试材，研究1-甲基环丙烯（1-MCP）处理对该桃的贮藏效果的影响。试验结果表明：使用500mL/L浓度的1-MCP熏蒸处理的“24号”桃在5℃下贮藏28d,3d货架期（室温17℃）后的果肉褐变指数为31%；而在5℃冷藏的桃果肉褐变指数货架期后为62%。1-MCP处理能够显著地抑制“24号”桃在贮藏过程中果肉褐变。     

帐内不同装载量与1-MCP处理桃贮藏效果的关系

目的:研究室温条件下进行1-MCP处理时,帐内不同装栽量对桃的贮藏效果的影响;方法:以久保桃为原材料,采用综合评判确定装载量对1-MCP处理桃贮藏效果的影响;结果:1-MCP处理可以有效地抑制常温货架期间桃果实的呼吸作用和乙烯生物合成、抑制果皮细胞膜透性、丙二醛含量、超氧化物歧化酶活性(SOD)和果实硬度变化等,一定程度延缓了果实的后熟衰老进程,较好地保持了果实的品质;结论:用塑料帐密封进行1-MCP处理时,帐内装满果实处理(A)与半帐处理(B)之间处理效果没有明显的差异,在实际应用中,可以不必过多考虑果实装载量对1-MCP处理效果产生的影响.     

1-MCP处理对磨盘柿减压贮藏品质及生理变化的影响

以磨盘柿为试材,通过对不同浓度1-甲基环丙烯(1-MCP)处理果实在减压冷藏期间主要生理生化指标、贮藏品质变化规律的分析,探讨了1-MCP处理对果实减压冷藏保鲜效果的影响。结果表明:1-MCP处理明显抑制了减压贮藏果实硬度、可溶性单宁含量的下降;同时也较好的抑制了果实可溶性固形物(去除单宁后)、丙二醛、膜相对透性和PPO活性的升高,并且能使果实在贮藏期间保持较高的SOD活性,但对可滴定酸含量的变化没有显著影响;减压贮藏果实适宜的1-MCP处理浓度为1.0μL/L。     

1-MCP处理对新高梨冷藏保鲜效果的影响

以新高梨果实为试材,通过对1-甲基环丙烯(1-MCP)处理新高梨冷藏期间主要生理指标和感官指标变化规律的分析,研究了1-MCP处理对新高梨果实冷藏保鲜效果的影响.结果表明:1-MCP处理推迟了乙烯和呼吸高峰的出现,抑制了果实丙二醛(MDA)和果皮相对膜透性的升高,延缓其衰老,明显延缓了果实硬度的下降,抑制了可溶性固形物含量的升高,从而较好地保持果实在贮藏期间的品质和风味;对照和处理的可滴定酸(TA)含量无明显变化:1-MCP处理可以抑制果心褐变,但经过1-MCP处理却加速了果实的果皮褐变.     

1-MCP处理结合冷藏对西兰花品质的影响

研究了1-MCP处理对西兰花冷藏保鲜品质的影响。1-MCP处理浓度为1.5、2.5μL/L,冷藏期间每隔10d取样测定西兰花理化指标及营养成分。试验结果表明:与对照相比,1-MCP处理对于延缓西兰花可溶性固形物含量(TSS)、Vc含量及叶绿素含量的下降均有明显效果,并可抑制西兰花贮藏期间的呼吸强度。1-MCP处理提高西兰花过氧化物酶(POD)和超氧化物歧化酶(SOD)的活性,降低多酚氧化酶(PPO)活性,延缓了丙二醛(MDA)含量和细胞膜相对透性的升高,延缓了西兰花的衰老。1.5、2.5μL/L的1-MCP处理对西兰花的成熟衰老均有抑制作用,其中经2.5μL/L处理的西兰花的品质表现更好。这说明了冷藏结合1-MCP处理不仅较之普通冷藏更好地保持了西兰花的营养品质,同时也证明1-MCP在低温条件下仍可发挥正常作用。     

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