氢氧化钠处理对酶脱毛的影响

通过测定氢氧化钠处理液中总蛋白含量,处理后皮的膨胀率和收缩温度以及酶脱毛速度等研究了氢氧化钠处理对酶脱毛的影响。实验结果表明,氢氧化钠处理能加快酶脱毛的速度,有可能解决直接酶脱毛小毛不易脱净的问题,但可能更容易导致成革松面。     

一种新型脱毛酶糊的应用探索

用酶法脱毛取代灰碱法脱毛是解决制革生产中硫化物污染的重要途径之一。本文对一种新型脱毛酶糊用于猪皮酶脱毛进行了试验,试验考察了脱毛温度与脱毛效果,酶糊浓度和用量与脱毛效果,皮块含水量与脱毛效果、皮块脂肪含量与脱毛效果等关系,并测定了脱毛处理液中蛋白质的含量。实验结果表明：在２６￣３８℃范围内本酶糊用于猪皮酶脱毛较完全可靠。     

响应面法优化牛皮酶法脱毛工艺

研究旨在探求复合酶脱毛的最优工艺条件,并为牛皮的开发利用提供了一定的理论基础。本试验以牛皮酶法脱毛过程中加酶方式、酶活力配比、酶液浓度、酶解时间、酶解pH、酶解温度等为研究因素,在单因素实验基础上进行复合酶脱毛方法,结合响应面法对复合酶脱毛工艺进行优化。结果表明,碱性蛋白酶和中性蛋白酶采用先后加入的酶解方式,得到了碱性蛋白酶和中性蛋白酶的最适酶活力配比、酶解温度、酶液浓度、酶解时间、pH值,测得综合评分为0.756。响应面法分析结果表明,酶解温度和酶液浓度的交互作用对脱毛效果的影响显著,而其他因素交互作用不显著。     

亚麻/棉针织物酶抛光工艺探讨

通过实验选择出用于亚麻／棉针织物酶抛光整理的合适的酶剂，确字最佳酶用量、处理温度、时间、搅拌程度，以及表面活性剂与酶的相容性，证实酶抛光整理对麻类针织物的产品开发重要性。     

表面活性剂对牛仔布生化酶洗效果的影响

通过在牛仔布生化酶洗过程中加入不同种类的表面活性剂试验,分别分析了阴离子表面活性剂、阳离子表面活性剂和非离子表面活性剂对牛仔布生化酶洗处理的影响规律。试验表明各种表面活性剂对于不同牛仔布的酶洗效果影响规律基本相似,随浓度不同,各种表面活性剂对酶活力和反应速度的影响规律有所不同。     

酶脱毛机理的研究(Ⅷ)——在酶脱毛过程中,不同预处理对胶原损耗的影响

各地在试验研究和推广应用酶脱毛新工艺过程中,由于工艺条件控制的不同,产品质量亦有差异。本文试图通过酶脱毛前的各种不同预处理、相同酶脱毛工艺的试验研究,测定酶脱毛浴液中的胶原含量,从胶原损耗情况看不同预处理的酶脱毛工艺对产品质量的影响。     

表面活性剂对纤维素酶水解过程的影响

分别以湿氧化、稀酸常压水解和蒸汽爆破预处理麦草为底物,考察了不同表面活性剂及用量对纤维素酶解过程的影响.实验表明,添加表面活性剂对纤维素酶水解过程有明显影响;添加非离子型表面活性剂(PEG6000、吐温80)可以提高纤维素的可溶性、可发酵糖的转化水平,其中向湿氧化处理的麦草中加入PEG6000后转化水平提高得最大;而添加离子型表面活性剂对酶解起抑制作用.非离子型表面活性刑和纤维素水解底物的最佳比例大约是0.05 g/g DM.     

染苑精粹

表面活性剂预处理对羊毛纤维酶解的影响2013111采用各种表面活性剂对羊毛纤维进行预处理(浴比为1∶50,20～90℃处理60 min),再用蛋白酶进行酶处理(浴比1∶150,50℃处理3 h),研究预处理对羊毛纤维酶解的影响。结果表明,采用阴离子表面活性剂预处理,会加速羊毛纤维的酶解;在较高的表面活性剂浓度条件下,随着表面活性剂吸收量的增加,羊毛纤维的溶解率增大;碱性脂肪酸预处理,会极大地促进羊毛纤维的酶解,这是因为,高温条件下的碱性脂肪酸预处理会损伤羊毛纤维表面,剥除羊毛纤维表层的鳞片,改变羊毛纤维内部结构,从而提高蛋白酶对羊毛纤维的作用,增加羊毛纤维的溶解率。     

酶脱毛工艺中酶软化的作用

本文阐述了猪皮酶脱毛工艺中,软化剂对胶原蛋白、胶原纤维以及弹性纤维的作用,叙述了酶脱毛后、基底膜的状况以及酶软剂对它的作用。提出酶脱毛后,以软化剂做适当的处理是必要的。     

表面活性剂对酶与明胶作用体系的影响

为了正确将表面活性剂使用到制革的酶处理工序中,本试验分别在胰酶和AS1.398酶溶液中添加质量浓度10%的明胶和不同量的十二烷基苯磺酸钠(阴离子型表面活性剂)、十二烷基三甲基氯化铵(阳离子型表面活性剂)和平平加O(非离子型表面活性剂),来测定不同表面活性剂对酶活力和明胶水解程度的影响。试验表明:3种表面活性剂对酶活均起到激活作用;但添加阴离子型表面活性剂后,明胶的水解程度提高。为了探究它们在溶液中所起的主导性作用,在试验第二步,将3种表面活性剂加入到质量浓度0.4%明胶+酶的混合液中,研究混合液在37℃时的Zeta电位的变化。试验表明:加入阴离子型,Zeta电位的绝对值提升;加入阳离子型,Zeta电位从负变为正;加入非离子型,Zeta电位绝对值降低。结合实际制革生产中对皮革高性能的要求,研究表明:在进行酶软化时,应优先选择非离子型表面活性剂。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press