溶解度对大麦麦芽多酚含量和抗氧化力的影响

分析了35种不同溶解程度的大麦麦芽和相应协定糖化麦汁的总多酚含量和抗氧化力。相关性分析结果表明:麦芽的抗氧化力与其蛋白质含量呈高度显著的负相关性(r=-0.500,P<0.01),而与麦芽的库尔巴哈值、浸出物含量和游离总多酚含量之间呈显著的正相关性;麦汁的总多酚、抗氧化力和花色苷含量均与麦芽的蛋白质含量呈高度显著的负相关性,而与麦芽的库值、浸出物含量、游离总多酚和抗氧化力之间呈高度显著的正相关性。研究认为,大麦品种在决定成品麦芽和麦汁的抗氧化特性的同时,制麦工艺和麦芽的溶解度对其抗氧化力也有非常重要的影响。本文为啤酒生产中大麦麦芽品质的综合评价提供了新的参考。     

小麦组分含量与小麦芽β-葡聚糖酶活力的相关性分析

跟踪测定了小麦芽常规制麦过程中β-葡聚糖酶活力的变化,分析了不同阶段小麦芽β-葡聚糖酶活与原小麦β-葡聚糖含量、蛋白质含量、淀粉含量之间的相关性.结果表明:绿麦芽β-葡聚糖酶与原小麦β-葡聚糖含量呈负相关(P<0.10);干麦芽β-葡聚糖酶与原小麦β-葡聚糖含量呈显著负相关(P<0.05).绿麦芽、干麦芽β-葡聚糖酶均与原小麦蛋白质含量呈显著负相关(P<0.05).干燥过程中小麦芽β-葡聚糖酶活力增加与小麦水溶蛋白含量成负相关(P<0.10)、与小麦醇溶蛋白含量成显著正相关(P<0.05).     

大麦、麦芽、协定法麦芽萃取物及啤酒中β-葡聚糖含量的关系

通过选择低β-葡聚糖含量的大麦进行制麦试验,以直接了解降低β-葡聚糖所造成的问题。β-葡聚糖含量增加所带来的问题,迫切需要解决:即如何通过调整制麦工艺来减少β-葡聚糖的含量。大麦与成品酒中β-葡聚糖含量的关系至今并未十分清楚。此研究通过测定大麦、麦芽与协定法萃取物中β-葡聚糖的含量,从而确定它们之间的关系,并由此确定哪个可以更好的预测啤酒中β-葡聚糖的含量。大麦生长环境与基因型对这三者关系与预测啤酒中β-葡聚糖的含量也在本文中进行了研究。通过 Calcofluor-流动注射分析方法实现对60个大麦样品及其对应的麦芽、协定法细粉萃取物和啤酒中的β-葡聚糖含量进行了分析。结果显示麦芽协定法萃取物中β-葡聚糖的含量与用相应麦芽生产的啤酒中β-葡聚糖的含量有高度的相关性;大麦与啤酒中β-葡聚糖含量的相关性明显较低。此研究也证明了生长环境对大麦、麦芽、协定法萃取物和啤酒中β-葡聚糖含量的强烈影响;同时,基因组成对他们的影响也相当显著。     

麦芽抗氧化性与常规指标相关性分析

本文研究7种麦芽的6个抗氧化性指标与其原大麦抗氧化性指标的对比,并利用相关分析和主成分分析研究了麦芽抗氧化性指标与常规质量指标之间的关系。结果表明:大麦制成麦芽后,脂肪酸氧化酶(LOX)活力显著降低;ABTS自由基清除活性与还原力显著增加;过氧化氢酶(CAT)活力除国产大麦降低外,其他品种大麦都显著增加;DPPH自由基清除活性与总多酚除了个别品种外,变化不大。主成分分析和相关分析表明,DPPH、ABTS、还原力、总多酚和LOX等抗氧化指标与总酸、糖化力、总蛋白、可溶性蛋白、AN、脆度和β-葡聚糖含量等七个常规指标具有非常显著的相关性(p0.01),CAT活性与色度和β-葡聚糖含量具有显著的相关性(p0.05)。     

β-葡聚糖酶对SN1391小麦芽的品质影响研究

以小麦SN1391为试材,按三因素三水平正交设计进行实验得到9组麦芽,通过对麦芽品质分析研究小麦芽β-葡聚糖酶活与麦芽品质的关系。发现小麦芽β-葡聚糖酶活与麦芽浸出物含量、α-淀粉酶活力存在极显著正相关性(P<0.01);与糖化力、库尔巴哈值、α-AN、蛋白酶活力存在显著正相关性(P<0.05);与麦汁粘度、糖化力存在显著负相关性(P<0.05)。影响β-葡聚糖酶活力的工艺参数主次顺序为:浸麦度>焙焦温度>发芽温度。浸麦度为47%～48%、发芽温度为15～17℃、焙焦温度为80～81℃时SN1391小麦芽β-葡聚糖酶活力最高。     

通过糖化措施控制啤酒的抗氧化力

啤酒含有丰富的抗氧化物,其数量和组成不仅与原料有关,还与生产过程的控制有关。大麦和麦芽是啤酒中抗氧化物的主要来源,而酒花所提供的抗氧化物很少。糖化过程对抗氧化物活性和多酚物质的含量是非常重要的。麦糟的吸附作用、儿茶酚与表儿茶酚的聚合都会降低成品啤酒中多酚物质的含量。基于电子自旋共振原理的两种方法可以用于检测抗氧化物的活性。它们分别是：DPPH（2,2-二苯基-1-苦肼基）分析和使用游离电子自旋捕获剂PBN（N-3-丁基-a-苯基硝酸灵）进行的“延迟时间”分析。高效液相色谱库仑阵列检测器可用来检测各种多酚物质的含量。本文主要研究了抗氧化物质的成分以及糖化过程中它们与总抗氧化活性的相关性。DPPH含量的下降与麦汁中儿茶酚和表儿茶酚的含量有很好的线性关系（在不含酒花的麦汁中分别为R^2=O.970,R^2=0.96l;在含酒花的麦汁中分别为彤=0.949,R^2=0.956）。     

制麦过程中麦芽β-葡聚糖与还原糖含量的变化

以澳大利亚大麦Gairdner和国产大麦垦啤7号为材料,在16℃、湿度为90%的条件下发芽,研究了制麦过程中麦芽β-葡聚糖含量和还原糖含量的动态变化。对定量测定麦芽的β-葡聚糖,采用了羧甲基纤维素钠代替标准大麦β-葡聚糖的方法,发现二者在550 nm处吸光值呈显著的线性相关,因此该方法方便可行且成本低廉。结果表明:在发芽的前期,麦芽的β-葡聚糖含量快速减少,同时还原糖含量也快速增加;发芽后期,麦芽β-葡聚糖含量下降趋于平缓,而还原糖的增加速度也趋于稳定。同时,在发芽过程中麦芽β-葡聚糖含量和还原糖含量还呈显著的负性相关性。     

多元线性分析麦芽质量指标与啤酒风味稳定性的关系

麦芽对啤酒风味稳定性的影响主要是由于抗氧化物的存在。本文中,五个大麦品种分别在生产及微型制麦规模上进行制麦,将所得麦芽的质量参数（如糖化力、脆度、β-葡聚糖、抗自由基活性、还原力、脂氧化酶活性和壬烯醛潜力）与新鲜及强制老化啤酒的感官结果相互关联。利用多元线性回归研究麦芽的理化参数和啤酒感官之间的关系,结果表明麦芽的抗自由基能力对啤酒风味稳定性的影响最大,而且,所测得抗自由基能力与麦芽中多酚含量有良好的相关性;且对于麦芽和大麦而言两者抗自由基的能力非常相似,预示着大麦内源多酚在啤酒风味稳定中的重要作用。     

国产大麦蛋白质含量及酶活力变化对麦芽品质的影响

选用蛋白质含量不同的6种国产大麦,五种蛋白组分含量,蛋白酶活力变化及对其制成麦芽理化指标进行了研究。国产大麦蛋白含量较高,各蛋白组分因品种不同差异较大,参与大麦代谢活动的组分波动较大,贮存蛋白变化相对平稳,研究表明大麦蛋白酶活力与五种蛋白组分含量不具有相关性,而制成麦芽后,麦芽蛋白酶活力与麦芽泡沫蛋白成负相关r=-0.733(p<0.05),与麦芽盐溶蛋白成负相关r=-0.789(p<0.05),与麦芽库值成正相关r=0.694(p<0.05)。     

关于降解麦芽β-葡聚糖工艺的探讨

本文针对如何更好降解麦芽β-葡聚糖、提高过滤速度进行一些有益的尝试，不足之处，请大家指正。 不同大麦品种β-葡聚糖含量差别很大，降解麦芽肛葡聚糖的方法也有所不同。总体上说，降解麦芽β-葡聚糖的原则有：缦麦度越高，越有利于半纤维素和麦胶物质分解；     

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