基于MTG酶催化的乳铁蛋白对羊毛织物抗菌整理

针对羊毛抗菌整理问题,利用新型生物交联剂MTG酶,将具有抗菌作用的乳铁蛋白通过生物催化交联的方式固定到羊毛织物上,对羊毛织物进行抗菌整理研究。采用紫外分光光度法测定乳铁蛋白的固定效率,从而探讨乳铁蛋白固定化的主要工艺参数,得出优化工艺条件,即MTG酶用量为30 U/g织物,温度为40℃,时间为2 h,乳铁蛋白质量浓度为5 mg/mL。研究结果表明,在此工艺条件下羊毛织物上乳铁蛋白的固定效率达到9%左右,整理后的羊毛织物对金黄色葡萄球菌的抑菌率达到57.95%,具有抗菌效果。     

溶菌酶在羊毛织物上的固定化

以羊毛织物为载体,研究了戊二醛交联固定溶菌酶的工艺条件。结果表明,戊二醛交联工艺的最佳条件为：戊二醛0.2%,交联时间2 h。溶菌酶固定化的条件为：溶菌酶5 g/L,固定化时间6 h,固定化pH值7.0,固定化温度4℃。在此工艺条件下制得的固定化溶菌酶的操作稳定性较好,使用6次后相对酶活仍保持在30%左右。     

羊毛织物的固定化溶菌酶抗茵整理

将固定化溶菌酶用于羊毛织物的抗菌整理.探讨了酶固定化的主要工艺条件,得出优化参数,即戊二醛浓度0.2%,固定化pH值7.O,固定化时间6 h,酶用量5 g/L.结果表明,在此工艺条件下整理的羊毛织物对金黄色葡萄球菌的抑菌率达到80.95%,具有良好的抗菌效果.     

羊毛织物固定化溶菌酶抗菌防毡缩整理

采用溶胶凝胶法将溶菌酶固着在羊毛织物上,实现抗菌和防毡缩整理.测试结果表明,固定化溶菌酶羊毛织物对金黄色葡萄球菌的抑菌率达到90.32%,且固定化酶的稳定性较好,织物水洗5次后,抑菌率仍保持在75.67%;羊毛织物面积毡缩率由15.50%减至3.71%,织物断裂强力由259 N 增至311N.     

羊毛织物的固定化溶菌酶抗菌整理

将固定化溶菌酶用于羊毛织物的抗菌整理。探讨了酶固定化的主要工艺条件,得出优化参数,即戊二醛浓度0．2％,固定化pH值7．0,固定化时间6h,酶用量5g／L。结果表明,在此工艺条件下整理的羊毛织物对金黄色葡萄球菌的抑菌率达到80．95％,具有良好的抗菌效果。     

MTG酶催化羊毛固定化溶菌酶及其抗菌性能

利用新型的生物催化剂微生物谷氨酰胺转胺酶(MTG)催化溶菌酶在羊毛织物上的固定化.通过SDS-PAGE方法研究了溶茵酶作为MTG催化底物的可行性,探讨了影响溶菌酶在羊毛上的固定化因素以及固定化后羊毛织物耐洗稳定性和抗菌性能.结果表明:羊毛织物在预处理后采用MTG催化可以实现溶菌酶的固定化,其中高锰酸钾预处理赋予了较好的固定化效果.实验得出的固定化条件为:溶菌酶用量2 g/L,固定化pH值7.0,固定化时间8 h,MTG用量20 U/g,在此条件下得到的固定化溶茵酶羊毛织物较吸附固定法具有更好的耐水洗稳定性及抗菌效果.     

D-塔格糖3-差向异构酶的固定化研究

从14种离子交换树脂和吸附树脂中,筛选出固定化效果较好的大孔弱碱性苯乙烯系阴离子交换树脂D301-Ⅲ为载体,以戊二醛为交联剂,通过先吸附后交联的方法对D-塔格糖3-差向异构酶的固定化进行研究。结果表明,最佳固定化条件为：加酶量为2.00mL/g（粗酶液/树脂）,吸附pH7.5,吸附时间为8h,吸附温度为30℃,戊二醛浓度为0.05%,交联时间为3h,固定化酶活回收率可达50%以上。固定化酶重复使用10次,酶活仍能稳定保持在初始酶活的65%以上,具有良好的操作稳定性。     

MTG酶催化接枝的羊毛织物抗菌防霉整理

利用新型生物交联剂微生物谷氨酰胺转氨酶(MTG酶)将ε-聚赖氨酸、溶菌酶和乳铁蛋白接枝到羊毛织物上,实现羊毛织物的抗菌防霉整理,并测试其抗菌、防霉效果.结果表明:对金黄色葡萄球菌,ε-聚赖氨酸接枝羊毛织物的抗菌效果最好,有1.6 mm的抑菌带形成;溶菌酶和乳铁蛋白接枝羊毛织物的抗菌效果较好,但无抑菌带生成.对大肠杆菌,ε-聚赖氨酸接枝羊毛织物有1.75 mm的抑菌带形成,效果最好;乳铁蛋白接枝羊毛织物虽无抑菌带生成,但菌落繁殖受到限制,效果较好;溶菌酶接枝样效果则有限.防霉剂SCJ -950、ε-聚赖氨酸和溶菌酶接枝羊毛织物均有一定的防霉效果.     

交联壳聚糖载体固定化柚苷酶工艺

以戊二醛为交联剂,壳聚糖为载体,采用交联-吸附偶联法固定柚苷酶,通过单因素和正交试验优化确定最佳固定化工艺。结果表明,柚苷酶的最佳固定化条件为：以质量浓度为3.5g/100mL的壳聚糖制备的凝胶微球为载体,凝结剂NaOH质量浓度1.0g/100mL、戊二醛体积分数7.0%、交联时间2.0h、pH 4.0、酶液质量浓度2.0mg/mL、25℃时吸附交联3.0h,得到固定化酶最高酶比活力为7.37U/g;与游离酶相比而言,固定化酶最适pH值与最适反应温度均无明显变化;固定化酶在不同温度(40、50、60℃)条件下重复使用7次,相对酶活力仍能保持在70%、60%和50%以上。     

酯化红曲霉原生质体制备及紫外线诱变育种

以红色红曲霉（Monascus ruber）为出发菌株,用混合酶制取原生质体并对原生质体形成条件进行探讨,并进行紫外诱变选育。采用50h菌龄的菌丝体,使用蜗牛酶（0.6%）＋溶菌酶（0.4%）＋纤维素酶（0.6%）的复合酶液,30℃酶解2h,在该条件下原生质体浓度可达7.8×106个/mL,再生率为7.3%。在最佳紫外照射时间80s下,突变株经筛选,得到一株酯化酶活显著提高、遗传性能稳定的诱变株HN215-6,其酶活达468.4mg/100mL,比出发菌株HN215提高了1.66倍。     

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