黄曲霉生长预测模型的建立及其在玉米储藏中的应用

玉米储藏条件不当很容易导致黄曲霉污染而产生对人畜有害的黄曲霉毒素,找到适当的储藏条件可以保证玉米安全储藏.对黄曲霉在不同的温度和环境相对湿度条件下的生长状态进行了研究.分析了黄曲霉菌落生长速度,找出了抑制黄曲霉生长的温度和湿度条件,对玉米安全储藏具有现实意义.     

不同储藏条件下玉米中霉菌对黄曲霉毒素B1的影响

研究了玉米储藏过程中霉菌数量与产生毒素黄曲霉毒素B1间的关系。将初始水分含量12.42%、14.30%、15.89%、17.62%、19.88%的玉米在30℃,相对湿度为75%、84%和92%的模拟环境中储藏35 d;测定霉菌总数及黄曲霉、木霉、黑曲霉的数量及黄曲霉毒素B1量。结果表明,玉米在相对湿度75%的环境中黄曲霉数量和产毒量最大的初始水分含量均是15.89%,其毒素量是初始毒素量的29.88倍;相对湿度84%的环境中黄曲霉数量最高的玉米初始水分含量是19.88%,产毒最多的玉米初始水分含量却是14.30%,其毒素量是初始毒素量的11.25倍;在相对湿度92%的环境中黄曲霉数量最高的玉米初始水分含量是17.62%,产毒最多的玉米初始水分含量是15.89%,其毒素量是初始毒素量的53.53倍。且在中、高湿环境中黄曲霉生长及产毒受其他微生物抑制较大。经相关性分析,在温度30℃相对水分75%储藏环境中,玉米上黄曲霉和黑曲霉总数均与黄曲霉毒素B1呈极显著正相关性(P<0.001,k≥0.997);在温度30℃,相对湿度84%环境中,玉米上黑曲霉总数与黄曲霉毒素B1呈显著正相关性(P<0.05,k=0.921)。     

低温等环境条件对黄曲霉菌产毒的影响研究

目的研究黄曲霉的产毒条件,预测影响毒素产生和积累的主要环境条件。方法选取接种量、温度、通氧量、pH值作为参考指标,根据单因素实验结果研究环境条件对黄曲霉毒素产生量的影响。结果培养条件各因素影响程度由高到低分别为:pH值温度转速接种量。结论通过改变储藏环境条件控制产毒菌产毒是一个高效易行的方法,较低的温度和良好的通风,即凉爽干燥的储藏环境,加上弱碱性条件可以有效降低黄曲霉毒素的产生。     

不同品质花生毛油中黄曲霉毒素的碱炼脱除效果

对黄曲霉毒素含量不同(AFB_1含量21.10～86.70μg/kg,AFT含量22.76～88.25μg/kg)、酸价(KOH)不同(5.09 mg/g和11.37 mg/g)的花生毛油分别进行碱炼脱酸,碱炼条件为理论加碱量及0.4%超量碱、碱液质量分数6.58%、碱炼温度55℃、碱炼时间20 min,检测碱炼前后花生油中黄曲霉毒素含量,分析碱炼对不同品质花生毛油中黄曲霉毒素的脱除效果。结果表明:碱炼可以使不同品质花生油中黄曲霉毒素的脱除率达95%以上,碱炼油中黄曲霉毒素含量降低至1μg/kg左右,达到国标限量和欧盟限量要求;对高酸价花生毛油进行两次碱炼脱酸,可以实现对黄曲霉毒素的深度脱除,碱炼油中黄曲霉毒素未检出,同时降低了碱炼过程的油脂损耗。     

辣椒贮藏过程中的防霉技术研究

黄曲霉毒素是黄曲霉菌产生,而产生黄曲霉毒素的因素较多,其中主要原因是环境温度和湿度。通过测定,在自然室温下黄曲霉毒素在次年3月份之前增长速度缓慢,从4月份起增长速度加快;在复合薄膜包装、自然装满、自然密封的条件下贮藏更容易技术推广。另外,在复合薄膜包装、压实装满、自然密封的条件下,通过不同温度下对黄曲霉毒素产生情况的测定,黄曲霉毒素在5、10℃条件下基本不产生。     

储粮中黄曲霉毒素检测和预警方法研究进展

黄曲霉毒素是严重影响食品安全的真菌毒素,粮食在不良的储藏条件下很容易受到该毒素的污染,监测和防控黄曲霉毒素污染是国内外广泛关注的研究热点。该文根据近几年国内外对黄曲霉毒素检测和防控的研究,重点探讨储粮中黄曲霉毒素检测及预警方法的研究进展,比较各种方法的特点,论述其适用的范围和进一步完善的可能性,期望为黄曲霉毒素的防控提供有意义的信息。     

不同贮藏条件下花生中黄曲霉毒素变化趋势

目的探寻不同贮藏条件下花生中黄曲霉毒素含量的变化趋势。方法以远杂9102和豫花15品种的花生和花生仁为研究对象,采用免疫亲和层析净化高效液相色谱法测定其在不同储藏的条件下黄曲霉毒素的含量。结果在整个贮藏过程中,远杂9102和豫花15品种的花生和含水量低于10%的花生仁的黄曲霉毒素含量为0,而含水量高于10%的花生仁的黄曲霉毒素含量随着贮藏时间的延长而升高。在接菌量相同的条件下,同一品种的花生仁黄曲霉毒素的含量随含水量增加而增高;在含水量相同的条件下,同一品种花生仁中黄曲霉毒素的含量随接菌量的增加而增高。在相同的贮藏条件下,远杂9102花生仁中黄曲霉毒素含量极显著高于豫花15。结论在贮藏过程中,花生中黄曲霉毒素的含量与花生是否带壳、含水量、初始带菌量和品种之间具有相关性。     

不同模拟温湿度环境下高水分玉米籽粒的品质变化

以京农科728玉米籽粒为研究对象,测定不同储藏温度(15、20、25、35、45℃)、湿度(40%～55%、75%、80%～90%)模拟储藏条件下小尺度高水分玉米籽粒的湿基水分、黄度、色差、粗淀粉含量及α-淀粉酶变化规律及其淀粉颗粒显微结构。结果表明,低温、高温低湿对玉米籽粒的霉变有一定的抑制作用;储藏过程中高水分玉米的水分、色差和黄度三者之间高度相关,且储藏环境湿度越高,三者之间的线性相关性越显著;此外,高水分玉米籽粒的品质变化受到储藏湿度的影响明显大于储藏温度对其的影响,譬如35℃-RH=80%～90%条件下的玉米籽粒在储藏第4天后即发生霉变,而35℃-RH=40%～55%、20℃-RH=75%、15℃-RH=75%等条件下的玉米籽粒可完好储藏至180 d,其中15℃和20℃条件下的玉米籽粒水分可达15%。     

饲料储藏品质指标研究

粗脂肪含量不同的三种饲料分别储藏在温度10℃、相对湿度80%～85%和温度30℃、相对湿度30%～35%的恒温恒湿箱中120天。在储藏前后测定了饲料中粗脂肪、水分、氨基酸总量、氨含量以及酸值和过氧化值。储藏中除前30天外,以后每隔15天测定分析饲料的酸值和过氧化值。结果表明:饲料经储藏后,粗脂肪含量降低,氨基酸总量也略有降低,但氨含量略有增加,饲料水分随储藏条件的相对湿度变化。随饲料储藏时间的延长,饲料酸值增加,饲料过氧化值增长较快。储藏温度和湿度对饲料储藏品质有影响。     

基于监测过氧化氢酶活性对储藏玉米AFB1污染的早期预警

早期预警是防控储藏玉米污染黄曲霉毒素B1(AFB_1)的重要手段。将不同含水量的玉米置于各种温度环境下进行储藏试验,研究过氧化氢酶活性变化与玉米污染黄曲霉毒素B1(AFB_1)的关系,结果表明,两者数据变化的趋势一致,AFB_1是过氧化氢酶活性的二次曲线函数(相关性系数大于0.95)。储藏温度和玉米含水量等条件可改变所含霉菌产生AFB_1和升高过氧化氢酶活性的速度,但不影响数值变化的趋势。在各种储藏条件下,过氧化氢酶活性变化可比玉米中AFB_1含量显著变化的起始点提前4~21d。因此,借助检测过氧化氢酶活性的方法可以早期预警储藏玉米污染AFB_1。     

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