聚乙烯复合膜用于新采樱桃的气调包装保鲜研究

以低密度聚乙烯、线性低密度聚乙烯和Hβ分子筛为原料,吹制获得新型聚乙烯复合膜,作为果蔬的保鲜包装膜.以新鲜樱桃为保鲜对象,探讨了复合膜的保鲜效果及分子筛含量的影响.实验测定了樱桃贮藏后的外观变化、呼吸强度、失重率、折光率和硬度等指标.结果表明,在室温下,A4保鲜膜的保鲜效果最好,使樱桃的保质期明显延长.     

基于主成分分析法分析不同包装材料对双孢蘑菇品质的影响

采用主成分分析法定量分析5 种包装材料处理对双孢蘑菇品质影响,建立综合评价函数,筛选最佳包装材料。结果表明,9 个检测指标可简化成2 个主成分,累积方差贡献率达到86.224%,能够较好地反映原始数据的信息;不同包装膜处理双孢蘑菇的品质综合得分从高到低为：低压高密度聚乙烯＞高压低密度聚乙烯＞聚丙烯＞线性低密度聚乙烯＞乙烯-乙酸乙烯共聚物＞对照。由此可见,包装袋有利于双孢蘑菇贮藏保鲜,且低压高密度聚乙烯包装材料的保鲜效果最佳,为双孢蘑菇的贮藏保鲜提供了科学和直观的依据。     

魔芋葡甘聚糖复合膜液对樱桃番茄的保鲜效果

以樱桃番茄为研究对象,研究魔芋葡甘聚糖(KGM)与乳酸链球菌素(Nisin)复合膜液对樱桃番茄的保鲜效果。分别采用不同浓度的KGM (3, 6和9 g/L)与Nisin (0.09 g/L)复合膜液对樱桃番茄进行涂膜处理,以无菌水处理为对照,处理后的樱桃番茄在室温(25℃)下贮藏,并定期测定其腐烂指数、失重率、可溶性固形物含量、硬度和过氧化物酶(POD)活性。结果表明, KGM-Nisin复合膜液涂膜处理能明显降低樱桃番茄的腐烂指数和失重率,有效减缓可溶性固形物含量和硬度的损失,能诱导POD活性维持在相对较高水平,其中,经6 g/L KGM与0.09 g/L Nisin复合膜液涂膜处理樱桃番茄的保鲜效果最好,说明涂膜处理能有效延缓樱桃番茄果实品质下降,为KGM-Nisin复合膜液在果蔬保鲜上的应用提供理论依据。     

魔芋葡甘聚糖/乙基纤维素复合膜对水果保鲜效果的影响

以葡萄、樱桃番茄、蜜桔为研究对象,采用魔芋葡甘聚糖(KGM)/乙基纤维素(EC)复合膜包裹后,置于35 ℃、湿度70%下贮藏,以感官评分、失重率、V_C含量和总酸含量为检测指标,研究KGM/EC复合膜对以上三种水果的保鲜效果,并与聚乙烯(PE)膜进行比较。结果表明,KGM/EC复合膜能很好地维持水果贮藏期间的感官品质,降低水果腐烂速度。与PE膜相比,KGM/EC复合膜包裹的水果V_C含量较高,总酸含量降低缓慢,但失重率变化较快,KGM/EC复合膜表现出对水果较好的保鲜效果。     

分子筛改性LDPE活性包装膜在草莓保鲜中的应用研究

新鲜草莓易腐烂,贮藏保鲜较为困难.为了延长草莓的贮藏期,本研究采用硅铝分子筛对低密度聚乙烯(LDPE)进行改性,制备了具有高透气性的改性LDPE包装膜.以LDPE膜包装的草莓和裸放草莓为实验对照组,在(5±1)℃的低温和加乙烯吸附药包的条件下,分别研究了LDPE和改性LDPE包装膜对草莓储存期的影响.实验中分别测定了草莓果肉中可溶性固形物含量、维生素C含量以及草莓的失重率、硬度、烂果率等指标.实验结果表明:对照组中裸放和用LDPE膜包装的草莓储藏期分别为3天和7天,而分子筛改性LDPE膜加乙烯吸附剂包装能够将草莓的贮藏期延长至11天,草莓的好果率、硬度和可溶性固形物含量等均明显高于对照组.该分子筛改性LDPE膜加乙烯吸附剂的综合包装方案能够有效延长草莓的低温贮藏保鲜时间.     

不同阻隔性包装材料对生菜保鲜效果的影响

为了研究不同阻隔性包装材料对采后生菜保鲜效果的影响,选择低密度聚乙烯膜(LDPE)、聚乙烯膜(PE)、高密度聚乙烯膜(HDPE)、乙烯—乙烯醇共聚物/聚乙烯复合膜(EVOH/PE)4种包装材料对生菜进行气调包装,并设置无包装组作为对照,置于4℃的冷库中贮藏。贮藏期间,定期对各组生菜感官、失重率、叶绿素含量、相对电导率以及袋内气体组分等指标进行测定。结果表明,第6天时,对照组生菜因失水严重而失去商品价值;EVOH/PE组中O_2即将耗尽,CO_2比例达到20.3%,袋内出现酒精气味;其它3组袋内O_2比例均先降低,在小范围内呈波动性变化,CO_2比例先升高后相对平稳。HDPE组贮藏时间达18d,保鲜效果最好。阻隔性适宜的包装材料可以有效提高生菜的保鲜效果,延长保鲜期。     

不同包装材料对樱桃番茄果粒品质及果蒂保水护绿作用

为探讨不同薄膜包装对樱桃番茄常温货架期保鲜效果的影响,以"千禧"樱桃番茄为试验对象,采用5种保鲜膜[聚乙烯(膜厚20μm):P1;低密度聚乙烯:P2;聚乙烯(膜厚13μm):P3;聚偏二氯乙烯:P4;聚氯乙烯:P5]包装樱桃番茄,通过评价常温贮藏期樱桃番茄的感官品质、包装膜内气体比例、果实呼吸速率和腐烂率,果实及果蒂失重率和色泽等品质指标,果蒂叶绿素含量、果肉可溶性固形物、可滴定酸和Vc等营养指标,筛选出适宜樱桃番茄的包装材料。结果表明:P1、P2、P3、P4包装膜均具有良好的保鲜作用,其中,P1、P2包装膜的保鲜效果更佳,主要表现在能够维持樱桃番茄良好的感官品质,以及在袋内形成高浓度CO_2和低浓度O_2的气体环境,抑制果实呼吸作用和腐烂,果实和果蒂的失水、变色和丙二醛产生,以及果蒂叶绿素降解,同时可保持果肉较高的可溶性固形物、可滴定酸和Vc等营养成分的含量。因此,P1、P2较适用于樱桃番茄的包装。     

不同包装膜处理杏鲍菇品质的主成分分析与综合评价

本文采用主成分分析法对气密性和阻隔性不同的包装膜包装处理下杏鲍菇品质的影响进行定量分析,建立综合评价函数,以此筛选最佳包装材料。结果表明,9个生理生化检测指标进行主成分分析可简化为2个主成分,累积方差贡献率为83.203%,能够较好地反映原始数据的信息;综合主成分分析显示,不同包装膜处理杏鲍菇的综合品质得分从高到低为:高压低密度聚乙烯(LDPE)聚丙烯(OPP)低压高密度聚乙烯(HDPE)聚乙烯(PE)乙烯-乙酸乙烯共聚物(EVA)未包装(CK)。由此可见,包装膜有利于杏鲍菇贮藏保鲜,且LDPE包装材料的保鲜效果最佳。     

复合软包装相关技术标准汇总

复合膜、袋标准一 G日/下10004一1998耐蒸煮复合膜袋 G日/下10005一,998双向拉伸聚丙烯旧0尸叫/低密度聚乙烯(LO户日复合膜、袋 已B/下3042一1 992洗衣粉包装 阳/丁17既8一1999包装术语工业包装袋热塑性塑料软质薄膜袋 G日/下}8893一2002商业零售包装袋 G日!8 1 92一200。液体食品无菌包装用纸基复合材料 G引8454一2001液体食品无菌包装用复合袋 G巳!8706一2002液体食品保鲜包装用纸基复合材料(屋顶包) OB/T187,一1993双向拉伸尼龙(BOpA)/低密度聚乙烯(L OPE)复合膜袋 OB21 97一1 996榨菜包装用复合膜.袋 日B/丁0003一1 994耐高温…     

黑木耳多糖/壳聚糖可食性复合膜的制备及对鲜牛肉的保鲜效果

为了开发具有优良保鲜效果的可食性复合膜,以黑木耳多糖（Auricularia auricular polysaccharide,AAP）和壳聚糖（chitosan,CS）为原料,通过测定复合膜理化指标、结构和抗氧化性,并将不同材料真空包装的冷鲜牛肉于4 ℃条件下贮藏10 d进行保鲜实验,研究不同AAP添加量对AAP/CS可食性复合膜理化性质和冷鲜牛肉保鲜效果的影响。结果表明：AAP的添加可增加AAP/CS复合膜的厚度、密度、溶解度、溶胀度、抗拉强度和1,1-二苯基-2-三硝基苯肼自由基清除率,并降低复合膜的水蒸气透过率和透明度;通过分析复合膜的傅里叶变换红外光谱,初步推测复合膜液中AAP和CS之间发生了相互作用。与市售聚对苯二甲酸乙二酯/聚乙烯复合真空包装组及CS膜包装组相比,AAP/CS复合膜包装组牛肉感官得分和pH值更高,菌落总数和硫代巴比妥酸反应物值更低。因此,AAP/CS可食性复合膜有望在食品抑菌保鲜等方面发挥积极作用。     

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.     

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