甘草、高良姜及其复合提取液对菠菜保鲜效果的研究

为探讨不同中草药提取液对菠菜保鲜效果的影响,配制了料液比为1∶10(g∶mL)的甘草、高良姜及其复合提取液,对菠菜进行浸泡处理5min,以蒸馏水浸泡为对照,置于(3±1)℃条件下贮藏,通过感官品质评定和测定腐烂率、失重率、呼吸强度、可滴定酸含量、Vc含量及叶绿素含量,研究了3种中草药提取液处理对菠菜贮藏保鲜过程中品质的影响。结果表明:与对照相比,3种提取液处理均可在不同程度上提高菠菜贮藏期间的感官品质,降低菠菜的腐烂率,抑制菠菜呼吸强度和失重率,减缓可滴定酸、Vc及叶绿素含量的降解。其中料液比为1∶10(g∶mL)的复合提取液对菠菜的保鲜效果最佳,显著优于对照(P<0.05)。     

蜂胶提取物对草莓室温保鲜效果的研究

为研究蜂胶乙醇提取物对草莓室温下的保鲜作用,以1%、2%、4%、6%浓度的蜂胶提取物作为保鲜剂,对草莓进行涂膜并在室温(24.5℃±)条件下贮藏,对不同涂膜处理后的草莓进行硬度、呼吸强度、可溶性固形物含量、可滴定酸含量、Vc含量、失重率、腐烂率等生理指标的测定。结果表明:在室温(24.5℃±)条件下,2%蜂胶提取物可以显著降低果实的呼吸强度、失重率和腐烂率,有效保持果实硬度,延缓可溶性固形物的降解,延缓果实可滴定酸和Vc含量的下降速度,维持果实原有品质,延缓果实成熟衰老。     

壳聚糖处理对辣椒保鲜效果的研究

以"苏椒5号"为试材,研究了(15±5)℃贮藏条件下0.5%,1%,1.5%低分子壳聚糖(CTS)溶液涂膜处理对辣椒保鲜效果的影响。结果表明:与对照辣椒果实相比,低分子壳聚糖处理能显著抑制贮藏期间辣椒的呼吸作用,降低辣椒的腐烂率和失重率,保持表皮绿色较高的叶绿素含量,减缓Vc的损失,维持较高POD活性。比较三种浓度的效果,以1.5%壳聚糖处理的效果最好。     

油用牡丹丹皮提取液对青椒的保鲜效应

利用超声波、水煮、蒸馏三种方法提取的油用牡丹丹皮液处理青椒进行保鲜效果研究,测定品质指标:质量损失率、腐烂率、果实硬度、可溶性固形物、叶绿素含量、细胞膜透性、维生素C、可滴定酸。结果表明:三种丹皮处理液对青椒保鲜效果优于空白对照,其中蒸馏处理液能有效降低青椒果实质量损失率和霉变率,明显延缓果实变软和膜透性的增加,有效抑制果实VC、可溶性固形物、可滴定酸的减少趋势,有较好的保鲜效果。     

不同复合保鲜剂处理对青椒采后贮藏品质的影响

以青椒为试材,选取1-甲基环丙烯(1-methylcyclopropene,1-MCP)、SO_2保鲜剂、乙烯吸收剂3种保鲜剂,通过两两组合的形式(1-MCP+SO2保鲜剂、1-MCP+乙烯吸收剂和SO_2保鲜剂+乙烯吸收剂)对青椒进行处理,测定贮藏期间青椒的品质和生理相关指标。结果表明,1-MCP+SO_2保鲜剂处理组保鲜效果较好,贮藏20 d后,青椒果实还原糖含量、VC含量、可滴定酸含量和叶绿素含量分别高于对照组15.17%、20.36%、16.32%、5.68%,且对照组青椒果实的失重率、腐烂率和乙烯呼吸速率分别是1-MCP+SO_2保鲜剂处理组的2.7、2.9、1.8倍,可见3种保鲜剂组合对青椒还原糖含量、VC含量、可滴定酸含量和叶绿素含量的下降均有抑制作用,并且可降低青椒果实的失重率、腐烂率和乙烯生成速率。     

硅藻土附载丁香酚缓释处理对不同品种草莓品质影响的比较

以4个品种草莓(晶瑶、晶玉、甜查理和宁丰)为试验材料,将丁香酚附载于硅藻土缓释,研究了不同品种、丁香酚缓释处理下草莓的保鲜效果。研究表明,晶瑶草莓贮藏保鲜效果优于晶玉、甜查理和宁丰三个品种草莓,货架期更长,保鲜品质由优至劣依次为:晶瑶、甜查理、宁丰、晶玉。在冷藏(4±1℃)过程中,丁香酚缓释可抑制草莓果实腐败,延缓果实质量损失和果肉可溶性固形物、可滴定酸、还原糖、Vc含量的降低,还能抑制MDA含量的上升以及SOD、POD、CAT等抗氧化酶类活性下降,对保持草莓果实的感官品质也具有积极作用;贮藏9 d时,经丁香酚缓释处理的晶瑶草莓腐烂率和失重率分别为31.50%和1.33%,可溶性固形物、可滴定酸、还原糖、Vc含量分别为8.83%、0.577%、5.72%和31.46 mg/100 g,MDA含量为23.11 nmol/g、SOD、POD、CAT活性分别、261.68 U/mL、1.65 U/mg、52.49 U/g。总而言之,硅藻土附载丁香酚缓释处理对草莓具有一定的保鲜作用,且不同品种草莓之间具有一定差异。     

三氧化氯对"秦美"猕猴桃保鲜及贮藏品质的影响

以"秦美"猕猴桃为材料,研究了二氧化氯对其保鲜及贮藏品质的影响.将猕猴桃分别浸入0、20、40、80、100mg/L的二氧化氯溶液中10min,沥干后贮存于温度为1～2℃,相对湿度为90%～95%的机械冷库中,以后每月取样,对其硬度、可溶性固形物、呼吸速率、乙烯释放速率、可溶性糖、可滴定酸、Vc含量等指标进行测定.结果表明,适宜浓度的二氧化氯处理可延缓猕猴桃果实硬度的下降,抑制乙烯的释放速率,并保持了可溶性糖、可滴定酸和Vc的含量,同时也对猕猴桃果实贮藏后期的腐烂有明显的抑制作用,延缓了果实的衰老,从而延长了其货架期.综合考虑,认为80mg/L的二氧化氯处理10min对"秦美"猕猴桃的保鲜效果最为理想.     

不同溶剂提取穇子多酚的抗氧化性及对龙眼保鲜作用的研究

本文采用不同溶剂提取穇子多酚,并对其抗氧化性和保鲜作用进行了研究。结果表明：穇子多酚消除DPPH自由基的能力大于BHT接近Vc;还原能力接近BHT与Vc;低浓度条件下对羟基自由基的清除能力均低于BHT与Vc,高浓度时则接近BHT。经过穇子多酚处理的龙眼果实在可滴定酸含量方面优于茶多酚和Vc处理组,在失重率、腐烂率、Vc含量、还原糖和总糖含量方面接近于茶多酚和Vc。整体而言,穇子多酚都表现出较好的抗氧化活性和保鲜作用,其中以酸性乙醇提取的效果最好。可作为天然保鲜剂进行进一步开发与利用。     

低功率微波处理对蓝莓采后品质变化的影响

用32.5 W低功率微波和不同时间处理蓝莓果实,研究在(0±1)℃条件下蓝莓果实的呼吸强度、超氧化物歧化酶(superoxide dismutase,SOD)活性、过氧化物酶(peroxidase,POD)活性、花色苷和丙二醛(malondialdehyde,MDA)含量以及总可溶性固形物(total soluble solids,TSS)、可滴定酸含量及腐烂率的变化规律,探索低功率微波保鲜蓝莓果实的可行性。结果表明,恰当的低功率微波处理蓝莓明显降低了果实的腐烂率、呼吸强度和丙二醛含量,提高了SOD活性和POD活性,延缓了可溶性固形物、可滴定酸和花色苷的降解,且32.5 W低功率微波处理2 min的保鲜效果最优,保持蓝莓果实采后的品质。     

壳聚糖复合涂膜对草莓保鲜的影响

迷迭香提取物、CaCl2、亚硫酸钠分别与壳聚糖复配涂膜研究草莓的贮藏保鲜技术,通过测定贮藏过程中草莓果实的营养成分、感官品质等指标,探究草莓在低温冷藏条件下的成熟衰老过程和不同保鲜剂处理对草莓贮藏品质的影响。结果表明:壳聚糖复配迷迭香提取物和壳聚糖复合CaCl2涂膜保鲜液均可显著地(P<0.05)减缓草莓的可溶性固形物、可滴定酸、Vc、还原糖含量的下降,抑制草莓细胞膜渗透率变化和果实的腐烂软化,保持草莓的硬度等贮藏品质。亚硫酸钠-壳聚糖处理可维持草莓的还原糖含量,延缓可滴定酸和Vc含量的下降。其中,1.5%壳聚糖+0.3%迷迭香提取物溶液浸渍涂膜5 min保鲜草莓效果最好,1.5%壳聚糖+2.0%CaCl2溶液浸渍涂膜5 min次之。     

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