NO熏蒸对冷藏枸杞鲜果品质影响的研究

为研究NO熏蒸对冷藏枸杞鲜果品质的影响,以"宁杞七号"为试材,采用0、200、300 μL/L和400 μL/L的NO气体对"宁杞七号"熏蒸处理,熏蒸时间为3 h,以探究不同浓度NO熏蒸对低温3 ℃冷藏枸杞品质的影响。结果表明:NO处理均可有效抑制枸杞品质下降的速度;300 μL/L相比200 μL/L和400 μL/L的NO处理更能有效降低枸杞鲜果的腐烂率,抑制果实呼吸强度上升及减缓果实硬度和抗坏血酸含量的下降速度;较好地维持可溶性固形物、可滴定酸、还原糖和可溶性糖含量,使枸杞鲜果在贮藏结束后仍然保持较好的贮藏品质。相比较而言,300 μL/L的NO熏蒸处理对冷藏枸杞鲜果贮藏品质的保持效果较佳。     

NO熏蒸对冷藏枸杞鲜果糖代谢及基因表达的影响

为研究NO熏蒸对冷藏枸杞鲜果糖代谢及基因表达的影响,以“宁杞七号”枸杞鲜果为试材,采用300μL/L(0μL/L NO为对照)NO气体对其熏蒸处理3 h,于（3.0±0.5）℃贮藏36 d。结果表明：300μL/L NO处理有利于提高果实可溶性固形物含量,抑制果实可溶性糖含量和果实硬度的下降,显著降低贮藏前期果实（0～12 d）中性转化酶活力和贮藏后期（24～36 d）酸性转化酶活力及Lb AI的相对表达量（36 d）(P<0.05);抑制蔗糖合成酶活力和降低贮藏第18天Lb SS的表达水平,防止蔗糖过度分解;同时NO熏蒸使果实蔗糖磷酸合成酶活力始终保持较高水平,贮藏第18天Lb SPS相对表达量显著高于对照组（P<0.05）。NO处理通过诱导糖代谢相关酶基因表达,维持糖代谢平衡,保持果实细胞壁张力从而减缓果实软化。     

NO熏蒸处理对冷藏枸杞鲜果细胞壁代谢的影响

为了探明NO熏蒸处理对冷藏枸杞鲜果细胞壁代谢的影响,本文以"宁杞七号"枸杞鲜果为试材,采用300μL/L(0μL/L NO为对照)的NO气体对"宁杞七号"熏蒸处理3 h,于3±0.5℃条件下贮藏36 d,定期测定果实腐烂率、硬度、细胞壁代谢相关酶活力.结果表明:300μL/L NO处理抑制枸杞鲜果多聚半乳糖醛酸酶(po...     

高浓度CO2应激调控对秋季鲜枸杞贮藏品质的影响

为探究枸杞鲜果对应激气体的响应机制,开发安全、绿色、简便、无残留的枸杞鲜果诱抗保鲜技术。采取低浓度1-甲基环丙烯（1-methylcyclopropene,1-MCP）熏蒸结合20%、50%和80%浓度CO2 短时气体应激耦合处理,研究宁夏枸杞鲜果在温度（0±1）℃和相对湿度（93±3）%贮藏环境下的品质调控规律。结果表明：0.1 μL/L 的1-MCP 熏蒸24 h耦合50% CO2 30 min 熏蒸可有效延长枸杞鲜果的贮藏品质,明显降低鲜果的失重率、呼吸强度和腐烂指数;减缓脂氧合酶（lipoxygenase,LOX）活性和丙二醛（malondialdehyde,MDA）的积累,增强过氧化物酶（peroxidase,POD）和苯丙氨酸解氨酶（phenylalanine ammonia-lyase,PAL）的酶活性,从而提高鲜果的抗逆性。     

乙醇熏蒸处理对鲜切莲藕片褐变和活性氧代谢的影响

褐变是导致鲜切莲藕品质劣变的重要因素,本文选用150μL/L乙醇熏蒸处理鲜切莲藕2 h,研究乙醇对其酶促褐变和活性氧代谢的影响。结果表明,经过10℃下贮藏12 d后,与对照组相比,乙醇处理后的鲜切藕片褐变度降低了6.49%,L*值提高了21.44%。乙醇处理也能通过抑制苯丙氨酸解氨酶和多酚氧化酶活力来抑制鲜切莲藕酚类物质的合成及氧化。在贮藏末期,对照组的可溶性醌含量是乙醇处理组的1.15倍。此外,乙醇处理可有效维持过氧化氢酶和过氧化物酶活性和抗坏血酸含量。经过12 d的贮藏后,乙醇处理后的鲜切莲藕的O₂^-·生成速率和H₂O₂积累分别是对照组的87.69%和79.17%。综上,乙醇熏蒸处理可能通过抑制酚类物质代谢,提高抗氧化能力,从而延缓鲜切莲藕褐变的发生。     

褪黑素对低温贮藏期间荠菜衰老和抗氧化能力的影响

以‘板叶’荠菜为实验材料,采用100 μmol/L褪黑素浸泡处理10 min,研究2 ℃贮藏期间褪黑素处理对荠菜品质和抗氧化能力的影响,并观察荠菜叶片细胞叶绿体超微结构的变化。结果表明：100 μmol/L褪黑素处理明显降低了贮藏期间荠菜的呼吸速率,抑制了荠菜叶绿素的降解,减少了活性氧自由基的积累,同时提高了超氧化物歧化酶（superoxide dismutase,SOD）、过氧化氢酶（catalase,CAT）、过氧化物酶（peroxidase,POD）和抗坏血酸过氧化物酶（ascorbate peroxidase,APX）等抗氧化酶活力以及抗氧化物质含量;在贮藏第18天,褪黑素处理荠菜的呼吸速率较对照降低了17.3%,抗坏血酸（ascorbic acid,ASA）、还原型谷胱甘肽（glutathione,GSH）含量分别是对照的1.18 倍和2.23 倍,SOD、谷胱甘肽还原酶（glutathione reductase,GR）活力比对照明显提升;超微结构观察结果表明褪黑素处理组荠菜叶片的叶绿体形状和基粒片层结构维持较好。结论：褪黑素处理能够有效抑制贮藏期间荠菜黄化,维持荠菜品质以及叶绿体结构完整,提高荠菜的抗氧化能力。     

‘东壁’和‘福眼’龙眼果实果皮褐变差异的生理机制

比较研究在温度（8±1）℃、相对湿度85%贮藏条件下‘东壁’和‘福眼’龙眼果实的果皮褐变差异及其与活性氧及酚类物质代谢的关系。结果表明：贮藏期间,‘东壁’龙眼果实的果皮褐变指数、果皮O2－·产生速率、丙二醛含量、细胞膜透性都显著低于‘福眼’龙眼,而活性氧清除酶（超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、抗坏血酸氧化酶（APX））活性和内源抗氧化物质（还原型抗坏血酸（AsA）、还原型谷胱甘肽（GSH））含量都显著高于‘福眼’龙眼;‘东壁’龙眼果实的果皮多酚氧化酶（PPO）和过氧化物酶（POD）活性都低于‘福眼’龙眼,而果皮花色素苷、类黄酮和总酚含量则高于‘福眼’龙眼。因此,采后‘东壁’龙眼果实较不容易发生果皮褐变,与其具有较强的活性氧清除能力,能减少O2 － ·积累,减轻膜脂过氧化作用,较好地保持龙眼果皮细胞膜结构的完整性,延缓PPO、POD与酚类物质接触而减少酚类物质的酶促氧化褐变有关。     

1-MCP熏蒸与高氧预处理对鲜枸杞贮藏品质的影响

以“宁杞7 号”枸杞鲜果为试材,研究90% O2 高氧预处理、1-甲基环丙烯（1-methylcyclopropene,1-MCP）熏蒸以及复合处理在（0±1）℃条件下贮藏30 d 对果实品质的调控作用。试验结果表明,高氧预处理能够显著降低枸杞果实的失重率、腐烂率,维持果实硬度,提高果实超氧化物歧化酶、过氧化氢酶及抗坏血酸过氧化物酶活性（P＜0.05）,保持果实的商品价值。1-MCP 熏蒸能显著降低果实呼吸强度（P＜0.05）、有效维持果皮光泽度、抗坏血酸含量、抑制果实丙二醛含量积累。面对1-MCP 熏蒸联合高氧预处理双向应激响应时,果实虽在一定程度上保持贮藏品质,但整体表现反而次于单一处理的贮藏效果。综上,1-MCP 熏蒸处理和高氧预处理均能有效提高枸杞果实贮藏品质,但二者复合处理不及单一处理保鲜效果,其双向应激造成的代谢机理有待深入研究。     

基于主成分分析的硝普钠处理对采后荔枝活性氧代谢的影响

为探究外源NO处理对荔枝采后活性氧代谢及生理品质的影响,本实验以不同浓度(10、50、100 μmol/L)硝普钠对采后荔枝进行浸泡处理,以清水处理为对照组,在4 ℃下定期测定荔枝的生理指标的变化,并进行相关性分析与主成分分析。结果表明：硝普钠处理能明显降低荔枝果实的质量损失率,抑制过氧化氢和超氧阴离子自由基等活性氧的产生和积累,减少膜脂过氧化产物丙二醛的产生和降低细胞膜透性,提高抗氧化酶如超氧化物歧化酶（superoxide dismutase,SOD）活力,延缓荔枝的衰老和褐变;10 μmol/L硝普钠处理能明显延缓荔枝褐变指数上升和降低果实细胞膜透性,而100 μmol/L处理组在贮藏中后期能更有效地降低果实质量损失率和提高SOD活力;主成分分析和品质综合评价结果表明,影响荔枝采后品质的关键指标为褐变指数、细胞膜透性、质量损失率和SOD活力,且100 μmol/L硝普钠处理的果实在贮藏后期（6 d后）的综合得分更高,贮藏品质最佳,表明硝普钠处理可以有效通过调节活性氧代谢延缓荔枝衰老褐变,延长其保质期。     

肉桂醛熏蒸处理对香菇采后抗氧化能力及多胺的影响

为探究肉桂醛熏蒸处理对香菇采后抗氧化能力和多胺的影响,本研究以‘香菇808’品种为材料,采用不同浓度（0、8、40、80?nmol/L）的肉桂醛（溶剂为体积分数30%乙醇溶液）进行熏蒸处理。通过测定总酚含量、抗坏血酸（ascorbic acid,AsA）含量、抗坏血酸过氧化物酶（ascorbate peroxidase,APX）活力、过氧化氢酶（catalase,CAT）活力、超氧化物歧化酶（superoxide dismutase,SOD）活力、谷胱甘肽还原酶（glutathione reductase,GR）活力、2,2’-联氮-二(3-乙基苯并噻唑-6-磺酸)（2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS）阳离子自由基清除能力、总抗氧化能力及游离态多胺含量指标,评价肉桂醛熏蒸处理的效果。结果表明：在4?℃低温下贮藏30?d后,各浓度肉桂醛熏蒸处理组的香菇抗氧化物酶（APX、CAT、SOD、GR）活力、ABTS阳离子自由基清除能力和总抗氧化能力均高于对照组,其中,40?nmol/L的肉桂醛熏蒸处理的效果最佳,但肉桂醛处理对总酚含量无明显影响。此外,各肉桂醛熏蒸处理组的游离态腐胺含量高于对照组,而游离态亚精胺、游离态精胺含量低于对照组。由此可知,肉桂醛熏蒸处理能够很好地提高香菇的抗氧化性及抗逆性,该研究结果为肉桂醛熏蒸处理在控制果蔬褐变和保鲜方面的应用提供了一定科学依据。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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