玉米秸秆酶解工艺条件优化

研究了不同的因素对纤维素酶酶解玉米秸秆的影响,包括时间、反应温度、底物浓度、酶用量等.采用5因素和4水平进行玉米秸秆酶解正交试验.结果表明,影响玉米秸秆酶解的因素为反应温度>水解时间>底物浓度>速度>酶用量:得到纤维素酶酶解玉米秸秆的最佳条件为反应时间48h,酶解温度55℃,底物浓度20g/L,速度130r/min,酶用量为200U/g.该研究为玉米秸秆的生物利用提供了理论依据.     

磷脂酶A1催化水解大豆浓缩磷脂的研究

研究了反应温度、加酶量、底物比(水/磷脂,mL/g)、反应时间对磷脂酶A1水解大豆浓缩磷脂的影响.采用正交设计方法,确定了各因素影响的显著性顺序为:底物比>反应温度>反应时间>加酶量;磷脂酶A1水解大豆浓缩磷脂的最佳工艺条件为:反应温度40℃,加酶量600μL,底物比12,反应时间10h.最佳工艺条件下产物酸值达129.6mgKOH/g.     

绿色木霉和黑曲霉协同酶解稻草秸秆纤维素的效果研究

采用双酶混合酶解可以缓解单一酶酶解过程中存在的产物累积抑制作用.对经过15%氨水预处理后的稻草残渣进行双酶(绿色木霉和黑曲霉)混合酶解实验.单因子实验发现纤维素酶解的最适条件为:纤维素酶加入量为20FPU/g底物、底物浓度为80g/L、pH值4.8、糖化温度为50℃;正交实验表明,酶的用量对酶解效果最为显著,其次是糖化温度,然后是pH,底物浓度对酶解得率的影响较小.最佳的酶解条件为:纤维素酶加入量30FPU/g底物、底物浓度60 g/L、PH4.8、糖化温度为50℃,在此条件下的酶解得率可达到80%.该研究为纤维素的有效利用提供了依据.     

脱脂豆粕制备高水解度大豆肽酶解条件的优化

目的:研究高水解度大豆肽酶解的最佳条件;方法:以水解度为指标,采用响应面分析考察底物浓度、酶浓度、反应pH等因素对水解度的影响;结果:高水解度大豆肽的最佳酶解条件为:底物浓度8.58%、加酶量8 800 U/g底物、pH 11.20、温度55℃、时间3.0 h,该条件下得到的大豆肽水解度为36.8%;结论:试验结果可为大豆肽的酶解工艺提供依据.     

酸酶结合法制备葡甘露低聚糖的工艺研究

本文采用酸酶结合的方法制备葡甘露低聚糖,通过单因素实验和正交实验确定最佳工艺条件为:酸解时间1.5 h,酶解温度55℃,HCl浓度0.07 mol/L,酸解温度85℃,加酶量6000 U/g,底物质量浓度80 g/L.因素影响大小顺序为:酸解时间＞酶解温度＞HCl浓度＞酸解温度＞加酶量＞底物质量浓度.     

中性蛋白酶水解花生粕的研究

选用中性蛋白酶对花生粕进行单酶水解研究.在单因素分析的基础上采用响应面分析方法对花生粕的酶解条件进行优化,得出最佳的水解条件为:底物浓度6%,反应时间3 h,反应温度44℃,pH6.7,加酶量6 500U/g底物,在此条件下理论水解度为7.63%.     

双酶酶解豆粕蛋白制备低苦味肽

利用不同蛋白酶酶解豆粕蛋白,根据蛋白溶出率和游离氨基氮含量选择最佳用酶为碱性蛋白酶。分析了酶解时间、酶/底物比、底物浓度对豆粕蛋白酶解的影响。在单因素实验基础上,采用Design-Expert7.0响应面分析法对三因素各水平进行优化。确定酶解最佳工艺条件为:碱性蛋白酶酶解时间4h、酶/底物比6900u/g、底物浓度6%,此时蛋白溶出率最高为74.38%。利用荧光探针法,确定了Flavorzyme风味蛋白酶酶解制备低苦味肽的最佳条件为酶解时间6h,酶/底物比80u/g。     

大豆活性肽酶解制备的工艺条件研究

以大豆分离蛋白为原料,选用碱性蛋白酶和风味蛋白酶,分别从酶解pH 值、酶解温度、酶用量和底物质量分数因素研究其对单酶酶解大豆分离蛋白的影响。并通过Minitab 软件,利用响应曲面试验优化双酶酶解工艺条件。结果表明,其最佳酶解条件为酶解pH7.7、碱性蛋白酶用量为110mg/g 底物、风味蛋白酶用量为90mg/g底物、酶解温度56℃、底物质量分数8%、酶解时间7h,所得的大豆活性肽的分子量主要集中在1000D 以下。     

木瓜蛋白酶制备大豆抗癌活性肽的条件优化

用木瓜蛋白酶对大豆分离蛋白进行酶解,制备大豆抗癌活性肽,并对其细胞生长抑制率、水解度和木瓜蛋白酶的最优作用条件进行研究。结果表明：在整个酶解过程中,大豆抗癌活性肽都具有明显的抗癌作用,但水解度与大豆抗癌活性肽的细胞生长抑制率之间不呈线性关系。底物质量浓度、酶用量、酶解温度、酶解时间和反应pH值都影响大豆抗癌活性肽的细胞生长抑制率。木瓜蛋白酶制备大豆抗癌活性肽的最优酶解条件为：底物大豆抗癌活性肽的浓度6g/100mL、酶用量7000U/g、酶解温度55℃、酶解时间4h、反应pH7.5,在此条件下得大豆抗癌活性肽细胞生长抑制率为28.13%。     

玉米胚芽肽酶解工艺初步研究

用2709碱性蛋白酶水解玉米胚芽蛋白,以反应温度、pH、加酶量、底物浓度、酶解时间为影响因素,酶解液蛋白质提取率为评价指标,进行单因素分析,并以此为依据采用正交实验设计,通过极差分析确定指标较优的工艺条件.结果表明:温度40℃、pH9.0、加酶量900U/g、底物浓度4.0%时,反应进行4h,胚芽蛋白提取率达85%左右.     

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