响应面试验优化失活酵母吸附猕猴桃汁中氯吡脲条件

以失活酵母菌为吸附剂,对猕猴桃汁中植物生长调节剂（氯吡脲）进行吸附。在单因素试验基础上,利用Box-Behnken响应面法对影响猕猴桃汁中氯吡脲吸附的失活酵母菌添加量、氯吡脲初始质量浓度、吸附时间关键因素进行优化,分析吸附对猕猴桃汁品质的影响。结果表明,失活酵母菌吸附氯吡脲的最佳条件为：失活酵母菌添加量28 mg/mL、氯吡脲初始质量浓度0.2 μg/mL、吸附时间3 h。在此条件下,氯吡脲吸附率为97.02%,与预测结果相符。失活酵母菌吸附氯吡脲对猕猴桃汁品质没有显著影响（P＞0.05）。     

壳聚糖对单宁酸的吸附性能研究

以活化后的壳聚糖为吸附剂，探究壳聚糖对水溶液中单宁酸的吸附性能。通过对实验过程中吸附动力学和吸附热力学的探究，采用粒内扩散模型、准一级动力学模型、准二级动力学模型对吸附动力学数据进行拟合处理，结果表明，壳聚糖吸附过程更符合准二级动力学模型(R²=0.996 5、R²=0.992 3);采用Langmuir等温吸附模型和Freundlich等温吸附模型对吸附热力学数据进行拟合，结果表明，壳聚糖吸附过程更符合Langmuir等温吸附模型(R²=0.995 9)。实验得出壳聚糖对水溶液中单宁酸的吸附属于单分子层的化学吸附。     

壳聚糖对天冬酰胺的吸附性能研究

采用壳聚糖对水溶液中天冬酰胺的吸附性能进行初步研究。采用粒内扩散模型、准一级动力学模型和准二级动力学模型对壳聚糖吸附天冬酰胺的动力学数据进行拟合,并采用Langmuir等温方程和Freundlich等温方程对其吸附等温线数据进行结果拟合。试验表明,当天冬酰胺的初始浓度分别为50、100、150 mg/L时,壳聚糖对天冬酰胺的吸附过程均符合准二级动力学方程(R^2=0.985 7～0.993 2)。壳聚糖对天冬酰胺的吸附等温线符合Langmuir等温吸附模型(R^2=0.978 8),其饱和吸附量为87.72 mg/g。壳聚糖对天冬酰胺具有一定的吸附能力。     

蔗糖溶液中新生磷酸钙对芦丁的吸附性能研究

采用新生磷酸钙为吸附剂研究了对蔗糖溶液中芦丁的吸附行为,考察了吸附时间、p H和芦丁的初始浓度对吸附量的影响。根据对吸附动力学数据进行的粒内扩散模型、准一级动力学模型和准二级动力学模型的拟合结果可知,在10%蔗糖溶液中,当芦丁的初始质量浓度分别为25,50和100 mg·L~(-1)时,新生磷酸钙对芦丁的吸附过程均可用准二级动力学方程描述(R~2=0.992 0~0.993 8)。最佳吸附p H在7.5左右;分别采用Langmuir等温吸附模型、Freundlich等温吸附模型对试验数据进行线性回归,表明吸附过程更符合Langmuir等温吸附模型(R~2=0.997 6),饱和吸附量为1.262 3 mg·g~(-1)。     

等离子体接枝法制备PET-g-AM纤维的铜离子吸附性能研究

考察了丙烯酰胺接枝改性聚酯纤维(PET-g-AM)的吸附性能,研究了改性纤维作为吸附剂对水溶液中Cu~(2+)的吸附过程,探讨了溶液pH、吸附温度、吸附时间、Cu~(2+)初始质量浓度对吸附量的影响。采用Freundlich、Langmuir等温吸附方程和准一级动力学、准二级动力学模型进行模拟,结果表明,改性后的聚酯纤维对Cu~(2+)具有良好的吸附效果,吸附过程符合Freundlich方程和准二级动力学模型。     

鸡蛋膜对苏丹红Ⅰ的吸附行为及机制研究

本文研究了厨余废弃物鸡蛋膜对食品污染物苏丹红I的吸附效果,通过条件优化及Zeta电位分析法考察了p H、吸附剂投入量、离子强度对吸附效果的影响,结果表明:在p H=6,10 g·L-1吸附剂投入量及1%Na Cl条件下吸附效果最佳,吸附平衡时间为140 min,平衡吸附量为1.25 mg·g-1;另外,对等温吸附过程进行了Langmuir、Freundlich、Temkin模型拟合及热力学参数计算,发现三种吸附模型均能较好地描述鸡蛋膜对苏丹红I的吸附过程(R2为0.86~0.99),但Freundlich模型的拟合效果更好(R20.97);ΔG0,ΔH0,ΔS0,表明苏丹红I与鸡蛋膜表面吸附位点在氢键及偶极间作用力下发生非均匀吸附,且该过程为吸热及熵推动的自发过程;对吸附过程进行了动力学模型拟合,发现准二级反应动力学方程拟合效果较好。结论:鸡蛋膜吸附剂对苏丹红I具有一定的吸附效果。     

复合凹凸棒介质对Cr（Ⅵ）吸附动力学和热力学研究

研究了复合凹凸棒介质(CAM)对Cr(Ⅵ)的吸附行为,拟合了吸附等温线,探讨了吸附动力学和热力学性质.结果表明,在实验范围内,CAM对Cr(Ⅵ)的吸附可以用Langmuir和Freundlich吸附等温方程来描述,但更符合Freundlich方程,相关系数均在0.98以上;二级动力学方程可以更好地描述吸附动力学规律;分别计算了热力学参数△G0、△H0、△S0,表明该吸附为熵驱动、吸热、自发的过程.     

复合凹凸棒介质对Cr（Ⅵ）吸附动力学和热力学研究

研究了复合凹凸棒介质（CAM）对Cr（Ⅵ）的吸附行为,拟合了吸附等温线,探讨了吸附动力学和热力学性质。结果表明,在实验范围内,CAM对Cr（Ⅵ）的吸附可以用Langmuir和Freundlich吸附等温方程来描述,但更符合Freundlich方程,相关系数均在0.98以上;二级动力学方程可以更好地描述吸附动力学规律;分别计算了热力学参数△G0、△H0、△S0,表明该吸附为熵驱动、吸热、自发的过程。     

蔗糖溶液中新生磷酸钙对单宁酸的吸附性能研究

研究了蔗糖溶液中新生磷酸钙对单宁酸的吸附特性。根据吸附动力学数据进行了粒内扩散模型、准一级动力学模型和准二级动力学模型的拟合,在蔗糖溶液中新生磷酸钙对单宁酸的吸附过程符合准二级动力学方程(R2=0.9994~0.9998),蔗糖分子的存在并不影响新生磷酸钙对单宁酸的吸附动力学行为,在不含蔗糖溶液中新生磷酸钙对单宁酸的吸附也符合准二级动力学方程(R2=0.9997~1.000)。新生磷酸钙对单宁酸的吸附呈单分子层吸附,符合Langmuir等温吸附模型(R2=0.9934~0.9963),蔗糖的浓度对吸附量有一定影响,在不含蔗糖体系中新生磷酸钙对单宁酸的吸附量最大,随着溶液中蔗糖浓度的升高,吸附量逐渐减小。当蔗糖溶液的浓度为分别为0.0%、5.0%、10.0%时,新生磷酸钙对单宁酸的饱和吸附量依次降低分别为125.00、91.74、86.96 mg/g。     

菠萝蜜果皮吸附亚甲基蓝的研究

以菠萝蜜果皮为原料,经粉碎制成粉末吸附剂。探究了菠萝蜜果皮吸附亚甲基蓝的性能。结果表明,在100 mL 100 mg/L的亚甲基蓝溶液中,菠萝蜜果皮最佳投加量为0.8 g,pH为5、温度为25 ℃、震荡时间为40 min。利用准一级、准二级动力学方程模拟菠萝蜜果皮吸附亚甲基蓝的动力学过程,利用Freundlich和Langmuir方程模拟其热力学行为。结果表明菠萝蜜果皮吸附亚甲基蓝的过程适合于准二级动力学、Freundlich模型。文中计算了焓变(ΔH0)、自由能(ΔG0)、熵变(ΔS0)等热力学参数,菠萝蜜果皮吸附亚甲基蓝的ΔG0小于0,ΔS0小于0、ΔH0小于0,说明菠萝蜜果皮吸附亚甲基蓝的过程是一个自发的趋于有序的放热过程。通过对吸附亚甲基蓝染料前后菠萝蜜果皮材料表面形貌进行分析,发现亚甲基蓝染料填充了菠萝蜜果皮表面的的空隙,导致吸附前后菠萝蜜的表面形貌发生了变化。     

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