6种常用饲料原料平衡水分吸附等温线研究

通过研究6种常用饲料原料（小麦粉、米糠、棉粕、芝麻粕、玉米蛋白粉、DDGS）的平衡水分吸附等温线，评价了修正Halsey（MHAE）、修正 Henderson（MHE）、修正Chung-Pfost（MCPE）、修正3参数GAB（MGAB）、修正Oswin（MOE）等5种农产品常用的吸湿方程对这几种饲料原料平衡水分吸附等温线的拟合效果，发现小麦粉平衡水分吸附等温线：MGAB方程在15、35℃时拟合效果最好，MHE方程在25℃时拟合最好；米糠平衡水分吸附等温线： MOE方程在15、25、35℃时拟合效果均为最好；棉粕平衡水分吸附等温线：MOE方程在15、25℃时拟合效果最好，MGAB方程在35℃时拟合最好；芝麻粕平衡水分吸附等温线：MOE方程在15、35℃时拟合效果最好，MHAE方程在25℃时拟合最好；玉米蛋白粉平衡水分吸附等温线：MHE方程在15℃时拟合效果最好，MCPE方程在25℃时拟合最好，MOE方程在35℃时拟合最好；DDGS平衡水分吸附等温线：MGAB方程在15℃时拟合效果最好，MOE方程在25、35℃时拟合效果最好。并选择拟合最佳的方程计算出6种饲料原料的绝对安全水分和相对安全水分，以期为饲料贮藏和防霉工作提供数据指导。     

稻谷吸附特性及安全水分研究

采用静态扩散平衡称重法,利用9种饱和盐溶液产生的稳定相对环境湿度,对糙米和稻壳的平衡含水率进行了测定,获得了其等温吸附曲线,分析了平衡含水率和相对湿度之间的关系。通过5种等温吸附模型对试验数据进行了拟合,发现糙米和稻壳的等温吸附曲线用Strohman-Yoerge(STYE)模型方程拟合的效果最好,并由该模型计算出糙米和稻壳在25、35、45℃下的安全水分,该安全水分与我国稻谷规定的安全收购与储藏水分相似。     

枸杞子贮藏中平衡含水率变化规律及等温吸附曲线研究

目的:研究不同初始含水率枸杞子在相对湿度35%~85%,温度分别为5、15、25、35℃条件下吸附平衡含水率变化规律,得到等温吸附曲线模型,通过模型可对枸杞子贮藏中的安全水分起预测作用。方法:采用静态吸附原理,根据目前在食品吸附中运用较多的6种模型对枸杞子实验吸附数据进行模拟分析比较。结果:枸杞子的平衡含水率随水分活度的增加呈上升趋势,其等温吸附曲线属于"J"型,而描述这一吸附特性的最佳数学模型为Halsey模型,并由模型方程计算得到枸杞子的绝对安全水分和相对安全水分。结论:该实验中的Halsey模型可作为枸杞子贮藏中平衡含水率的预测模型,为枸杞子安全水分的控制及科学贮藏提供参考。     

马铃薯全粉平衡水分吸附等温线与吸附等热研究

采用静态称重法在温度10～35℃、相对湿度11%～96%范围内测定了五种马铃薯全粉的平衡水分/平衡相对湿度(EMC/ERH)数据,确定了多项式方程、修正3参数Guggenheim-Anderson-de Boer(MGAB)、修正Halsey(MHAE)、修正Oswin(MOE)为适合的等温线拟合方程,采用多项式EMC方程分析马铃薯全粉的安全储运最大允许的含水率,在25℃、RH60%条件下,绝对安全水分是10.05%;在25℃、RH 70%条件,相对安全水分是12.64%。采用MHAE分析马铃薯全粉水分吸附等热,随着含水率增加到17.5%,马铃薯全粉水分吸附等热则以抛物线形式快速地减少,之后随着含水率增加,水分吸附等热则减少缓慢。在含水率22%,马铃薯全粉水分吸附等热接近纯水的吸附等热。     

甜菜粕对钙和铅的吸附性能研究

甜菜粕是重金属离子螯合剂和吸附剂。研究了溶液pH值、温度、时间及初始质量浓度等条件对甜菜粕(SBP)吸附轻金属离子Ca~(2+)和重金属离子Pb~(2+)的性能,并体外模拟在人体肠道环境条件(pH7.0、37℃)下,研究SBP对钙和铅的吸附性能和机理。结果表明:SBP对铅的螯合大于对钙的吸附;溶液pH值为7.0时吸附效果最佳;Ca~(2+)、Pb~(2+)分别在30、60min内达吸附平衡。在pH7.0和37℃的生理条件下,两种离子的吸附动力学过程均符合Lagergre方程二级吸附模型,SBP对Ca~(2+)的等温吸附平衡与Langmuir方程拟合度高,属单分子层吸附,而SBP对Pb~(2+)的等温吸附平衡与Langmuir方程拟合度不如Ca~(2+)高。     

采用一个多项式方程拟合粮食水分吸着等温线

假定粮食平衡水分(EMC)是相对湿度(RH)的多项式函数,也是温度(t)的线性函数,提出了一个方程EMC=C1RH3+C2RH2+C3RH+C4RH2t+C5RHt+C6t+C7,C1~C7是方程参数。此方程对我国主要粮种水分吸着等温线的拟合度指标决定系数R20.994,平均相对误差MRE%3.46,这些指标优于修正Chung-Pfost(MCPE)、修正Halsey(MHAE)、修正Henderson(MHE)、修正Guggenheim-Anderson-de Boer(MGAB)及修正Oswin(MOE)的拟合度指标。分析该方程拟合出的粮食吸着等温线,谷物解吸与吸附之间存在明显的滞后现象,而大豆滞后现象不明显。由拟合的解吸等温线分析30℃相对安全水分值,谷物低于14%,大豆为11.47%。     

几种高油脂食品等温吸湿规律的研究

研究了真空油炸莲子、真空油炸胡萝卜脆片、常压油炸胡萝卜脆片、常压油炸土豆脆片4种高脂食品的吸湿等温曲线。根据常用的5种等温吸附模型对4种物料的吸湿实验数据进行了拟合,比较了其拟合程度(R2)。结果表明,25℃条件下,4种高脂物料最适合的等温吸附模型都是Peleg模型,且拟合程度依次为真空油炸胡萝卜脆片、常压油炸胡萝卜脆片、真空油炸莲子、常压油炸土豆脆片。     

大豆水分解吸-吸附等温线拟合模型

为给在干燥、贮藏及运输过程中保证大豆的品质提供理论依据,实验测定了大豆在室温（25 ℃）条件下的水分解吸-吸附等温线。采用非线性回归分析,应用常见的5 种模型Oswin、Halsey、Hendenson、GAB、Chung-Pfost对大豆在室温条件下测得的水分进行解吸-吸附等温线拟合分析,以确定最佳拟合模型及其参数。结果表明：大豆的解吸等温线属于第Ⅱ种类型;吸附等温线属于第Ⅲ种类型;在整个水分活度范围内,大豆的解吸-吸附等温线均存在着滞后现象;最佳的解吸-吸附等温线拟合方程都是Oswin模型,它们的决定系数均高于0.993;Oswin模型拟合大豆解吸等温线的参数A和B分别为0.075和0.500,吸附等温线的参数A和B分别为0.075和0.498。     

面包吸附等温线的测定及测定方法比较

目的：研究不同方法对测定面包吸附等温线的影响及在25 ℃下面包含水率与水分活度的关系。方法：采用饱和盐溶液法（SSS）、动态水分转移规律分析仪法（DWT）和动态蒸汽吸附法（DVS）测定面包在25 ℃下和0.100～0.902水分活度范围内的水分吸附等温线,采用7种吸附模型拟合结果。结果：面包的吸附等温线属于Ⅱ型曲线。采用SSS法和DWT法测定整个面包吸附等温线的最佳拟合模型分别为Halsey模型和Peleg模型;采用DVS法测定面包瓤和面包皮吸附等温线的最佳拟合模型分别是Halsey模型和Oswin模型。同时,SSS法不限制面包体积和质量,但试验用时较长且高湿度下难以提供稳定湿度环境;DWT法不限制面包体积和质量且能提供稳定的湿度条件;相对于SSS法和DWT法,DVS法尽管可快速得到面包水分吸附等温线的结果,但该方法限制了面包的质量和体积且无法同时进行平行试验。结论：DWT法更适合面包吸附等温线的测定。     

芹菜平衡含水率的实验研究

在芹菜的加工和贮藏过程中,等温线是其重要性质之一。取相对湿度10%～90%范围,测定20℃、30℃和40℃条件下芹菜的等温解吸和吸湿平衡含水率,绘出等温平衡曲线,对4个模型和平衡含水率曲线进行拟合研究,结果表明,Modified-Hendenson模型对芹菜平衡含水率的拟合效果最好。     

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