复合天然抑菌膜对Cheddar干酪的保鲜效果

使用不同复合天然抑菌膜(无覆膜保鲜(空白)、酪蛋白酸钠-壳聚糖-纳他霉素膜(M1)、酪蛋白酸钠-壳聚糖-纳他霉素/溶菌酶膜(M2))对Cheddar干酪保鲜效果进行研究,在4℃冷藏条件下,对干酪感官、不同贮藏时间的水分含量、p H、滴定酸度、可溶性氮含量、融化性和油脂析出性、质构特性及SDS-凝胶电泳、微生物指标的变化进行测定。结果表明:与空白相比,M1和M2膜包装干酪的各项感官、理化指标较好,质构特性相对较优,并且M1膜包装干酪SDS-凝胶电泳图谱说明其蛋白水解程度相对较低,干酪溶液铺平板培养48 h后的菌落数(3.5×10~4CFU/m L)少于M2膜(6.8×10~4CFU/m L)和空白(9.2×10~4CFU/m L),因此,M1膜包装明显优于M2膜,并且M1膜和M2膜对Cheddar干酪均具有良好的抗菌保鲜性,可有效延长Cheddar干酪的贮藏期。     

基于Nisin对琼脂/卡拉胶基复合膜的改性及应用评价

为了防止微生物对蓝莓的侵害,改善传统石油基包装材料对环境造成的污染。研究采用琼脂、卡拉胶作为成膜基材,甘油作为增塑剂,以不同浓度的乳酸链球菌素（Nisin）作为抗菌剂来制备复合抗菌膜,对其理化指标及对蓝莓的保鲜效果进行综合评价。通过对抗菌膜的抑菌性、水溶性、光学性能、阻隔性能及机械性能进行全面分析得出以下结论,当复合抗菌膜中Nisin的质量分数为0.28%时,复合抗菌膜对金黄色葡萄球菌和李斯特菌的抑菌宽度为3.326 mm、1.812 mm,水溶性为45.01%,透光率为79.78%,抗拉强度为16.09 MPa,具有较好的应用特性。将含有0.28% Nisin的复合抗菌膜应用于蓝莓的保鲜研究中发现,在4 ℃和20 ℃的条件下,储藏期满时复合膜组的菌落数为4.20 lg cfu/g和2.46 lg cfu/g明显低于其他对照组,并且对减缓营养成分的流失有一定的作用。因此,试验制备的复合膜能有利于延长蓝莓的货架期。     

负载丁香酚/纳他霉素的玉米醇溶蛋白膜的制备、性能及其应用

以玉米醇溶蛋白、纳他霉素、丁香酚、甘油、乙醇为原料,采用流延法制备成负载丁香酚/纳他霉素的玉米醇溶蛋白膜,通过单因素实验对成膜工艺进行优化。并将负载丁香酚/纳他霉素的玉米醇溶蛋白膜涂膜于柑橘表面进行保鲜。结果表明:当玉米醇溶蛋白和80%乙醇固液比1∶10(g/mL),纳他霉素含量0.05%,丁香酚含量10ug/0.05%纳他霉素,甘油浓度为玉米醇溶蛋白的20%时,膜的拉伸强度7.6MPa,红外光谱图和差热分析图表明添加物没有改变玉米醇溶蛋白的主要结构且具有良好的相容性。柑橘表面涂膜保鲜实验结果表明,负载丁香酚/纳他霉素的玉米醇溶蛋白膜涂膜处理保鲜显著。     

热处理对鲜切哈密瓜品质及其微生物的影响

为研究热处理对鲜切哈密瓜品质及其微生物的影响,分别采用75、85、95℃热水对鲜切哈密瓜烫漂30、60s,在冷藏(5℃)过程中每2d测定鲜切哈密瓜的菌落总数、色泽、还原型抗坏血酸、总酸、可溶性固形物、相对电导率和渗汁率。结果表明:在热处理当天,95℃、60s处理杀菌的效果最好,菌落总数为28CFU/g,而对照的菌落总数为1.3×103CFU/g,两者相差约46倍;第10天时,对照组的菌落总数为1.8×108CFU/g,而含量最低的95℃、30s处理的鲜切哈密瓜的菌落总数为2.4×105CFU/g,两者相差750倍;在处理当天和贮存过程中,热处理对还原型抗坏血酸含量、总酸含量、可溶性固形物含量和渗汁率有一定影响,但对色泽几乎没有影响。     

石墨烯/壳聚糖抗菌膜的制备及其保鲜性能评价

研究了石墨烯/壳聚糖抗菌包装膜对冷鲜猪肉的保鲜效果。以醋酸为溶剂溶解壳聚糖,向壳聚糖溶液中加入石墨烯粉末,通过相转移法制备石墨烯/壳聚糖基复合抑菌薄膜材料。研究石墨烯含量对壳聚糖膜强度以及抑菌性能的影响。通过测试猪肉菌落总数、挥发性盐基氮、pH、脂肪氧化程度、透光率等来研究抗菌包装膜对猪肉品质的影响。结果表明:随着石墨烯的加入,复合膜的抑菌效果明显提高,当石墨烯的加入量为4%时,复合膜的拉伸强度为6.2MPa,断裂伸长率达到58%,猪肉保存72h后,菌落总数是5.0lg CFU/g,挥发性盐基氮达到8.9mg/100g,TBA值达到0.434mg/kg。抗菌薄膜可以显著地减缓贮藏期间猪肉菌落总数、挥发性盐基氮等指标的上升。常温下可延长冷鲜猪肉货架寿命3天。     

复合保鲜剂结合MAP对鲜切茄子贮藏品质的影响

为延长鲜切茄子的保鲜时间,研究单一气调包装(2%CO2+5%O2+93%N2)和保鲜液(1.5%壳聚糖+1%抗坏血酸+1%氯化钙+2%柠檬酸)结合气调包装对鲜切茄子品质的影响。以感官评分、褐变度、硬度、多酚氧化酶(PPO)活性和细菌总数为指标,分析鲜切茄子于(10±1)℃下贮藏8d内的品质变化。结果表明:贮藏8d后,对照组样品的L*值、硬度、PPO酶活性和细菌总数分别为75.66、7.41kg/cm2、68.77U/(min·g)和5.52lg CFU/g,而经保鲜液结合气调包装的鲜切茄子各指标分别为82.51、10.05kg/cm2、23.70U/(min·g)和2.87lg CFU/g。气调包装能够抑制鲜切茄子的褐变、萎蔫等感官品质的下降,并抑制PPO活性的增加和细菌的生长繁殖,尤其在结合保鲜液处理后效果更加明显,贮藏8d仍保持较好的品质。     

纳他霉素对鲜切莴苣表面微生物增殖与生理生化变化的影响

为了探讨纳他霉素处理对鲜切莴苣的保鲜效果,采用浓度为200mg/L纳他霉素溶液对新鲜莴苣进行喷雾和浸泡处理,研究了天然保鲜剂-纳他霉素对鲜切莴苣表面霉菌生长与生理生化变化的影响。结果表明,纳他霉素处理可以有效抑制莴苣表面霉菌的生长与增殖,保持了鲜切莴苣较高的花青素含量,降低了总酚和类黄酮含量降低鲜切莴苣PPO与PAL的活性,抑制了MDA的积累。实验结果证明纳他霉素处理对鲜切莴苣的衰老和腐烂有较好的抑制作用,尤其是喷雾处理的莴苣保鲜效果较好。     

高压二氧化碳处理对鲜切哈密瓜微生物与品质的影响

本实验以哈密瓜为原料,优化了清洗工艺,研究了高压二氧化碳（high pressure carbon dioxide,HPCD） 处理对鲜切哈密瓜贮藏期间（4 ℃避光贮藏8 d）微生物（菌落总数、霉菌和酵母菌总数）、感官指标（质量损失 率、质构、感官评价）、品质指标（可溶性固形物含量、pH值、VC含量）、酶（多酚氧化酶（polyphenoloxidase, PPO）、过氧化物酶）活力的影响。本研究首先确定了强酸电解水清洗25 min为最佳清洗工艺,清洗后鲜切哈密 瓜的菌落总数下降了0.81（lg（CFU/g））。2.5、3.5、4.5 MPa处理8 min后的鲜切哈密瓜在贮藏期间微生物数量显 著增加,PPO活力上升,且在贮藏8 d时,质量、硬度和VC含量分别下降了16.45%～42.70%、30.38%～48.97%和 96.25%～96.73%。本研究为HPCD技术应用于鲜切哈密瓜加工提供了理论依据。     

壳聚糖-普鲁兰多糖复合抗菌保鲜膜对冷鲜牛肉的保鲜效果

开发了一种适用于冷鲜牛肉保鲜的具有抗菌功能的可食性抗菌保鲜膜。将4 mg/mL的ε-聚赖氨酸(ε-PL)添加到壳聚糖-普鲁兰多糖溶液中,制备具抗菌功能的可食性复合抗菌保鲜膜,并验证该保鲜膜具有良好的理化特性和抗菌效果。冷鲜牛肉贮藏过程中优势致病菌(大肠O157:H7,单增李斯特菌和沙门氏菌)和菌落总数等指标检测结果表明,贮藏9天,对照组菌落总数就达到8.09 lg(CFU/g),而处理组增长较缓慢,第13天为5.94lg (CFU/g)。贮藏末期,处理组大肠O157:H7、单增李斯特菌和沙门氏菌较对照组分别减少了5.12,4.47 lg(CFU/cm2)和5.54 lg(CFU/cm2)。通过比较分析冷鲜牛肉贮藏过程中感官、质地、挥发性盐基氮(TVBN)、pH值、色度指标(a*/b*)等指标,表明该膜对于减缓冷鲜牛肉品质劣变具有显著效果。该保鲜膜对于控制牛肉品质劣变、延长货架期具有良好效果。     

超声-ε-聚赖氨酸盐酸盐复合处理对鲜切苹果的保鲜作用

为提高鲜切苹果品质、延长货架期,探究超声-ε-聚赖氨酸盐酸盐复合处理鲜切苹果的最优参数及其保鲜效果。采用Box-Behnken设计,以菌落增长数为响应值,通过响应面法确定超声-ε-聚赖氨酸盐酸盐复合处理鲜切苹果的最佳参数。根据菌落总数、霉菌和酵母、色差、V_C含量结果,评价超声-ε-聚赖氨酸盐酸盐复合处理对鲜切苹果贮藏期间的保鲜作用。结果表明,超声-ε-聚赖氨酸盐酸盐复合处理鲜切苹果的最优参数为:超声时间为10 min、超声温度为40 ℃、ε-聚赖氨酸盐酸盐浓度为0.2 g/L,切分前与切分后处理实际测定值分别为1.59 lg CFU/g、1.71 lg CFU/g,与预测值相对误差分别为3.92%、5.59%,拟合度高,模型可靠。利用优化的条件处理的鲜切苹果在4 ℃贮藏期间,细菌、霉菌和酵母增长速度显著低于（P<0.05）对照,V_C未受到明显破坏,切分前超声-ε-聚赖氨酸盐酸盐复合处理组色差上升速度低于对照组。响应面法优化的超声-ε-聚赖氨酸盐酸盐复合处理鲜切苹果是可行的,其中切分前超声处理效果较好,货架期比对照组延长4 d。     

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