基于单一酶的膨化辅料糖化工艺研究

为了简化啤酒糖化过程,降低生产成本,研究适合于耐高温α-淀粉酶的膨化辅料糖化工艺,本试验以麦汁浸出物收得率为主要考察指标,还原糖含量、原麦汁过滤速度为次要指标,兼顾色度和pH值等指标,得出适用于啤酒生产实际的以膨化大米为辅料生产啤酒最佳糖化工艺参数.结果表明,在相同的糖化原料的前提条件下,采用挤压膨化大米辅料糖化工艺和啤酒传统不膨化大米辅料糖化工艺相比,糖化麦汁浸出物收得率、还原糖含量和过滤速度均有明显提高,其它各项指标与对照样基本一致,均符合国家有关规定的要求.     

正交试验优化啤酒糖化工艺

为了探究以大麦芽和大米为原料的啤酒糖化工艺最佳条件,以麦汁浸出物收得率为评价指标,对大米添加量、水料比、52℃糖化时间和65℃糖化时间4个因素先进行单因素试验,然后利用正交试验对该工艺优化,最后进行方差分析显著性和验证试验。结果显示:大米添加量为32.5%,水料比为3.5∶1 mL/g,52℃糖化时间50 min和65℃糖化时间60 min条件下,麦汁收得率最高,方差分析显示,4个因素对该工艺影响均不显著,该试验准确可靠稳定。为研究添加大米辅料啤酒糖化工艺提供了试验依据。     

糖化工艺参数对膨化大米辅料麦汁α-氨基氮含量的影响

在100 L规模上,通过5因素5水平二次旋转正交组合试验设计,探讨膨化大米辅料酿造啤酒的外加酶糖化工艺参数对麦汁α-氨基氮含量的影响规律,得出最佳的糖化工艺参数.     

糖化工艺参数对膨化大米辅料麦汁收得率的影响

在100L规模上,通过五因素五水平二次旋转正交组合试验设计,探讨了膨化大米辅料酿造啤酒的外加酶糖化工艺参数对麦汁收得率的影响规律.最佳糖化工艺参数为:辅料含量为46.77%,料水比为1∶4.88,50℃蛋白质休止时间为60 min,63℃糖化时间为60 min,70℃糖化时间为30.35 min.     

响应曲面法分析小麦啤酒糖化工艺参数对麦汁α-氨基氮含量的影响

采用响应曲面分析法对影响小麦啤酒麦汁α-氨基氮含量的4个主要糖化工艺参数即小麦芽比例、水料比、52℃保温时间和65℃保温时间进行优化,建立了各因素对麦汁α-氨基氮含量影响的数学模型。结果表明,最佳糖化工艺参数为：小麦芽比例为42％,水料比为4．6,52℃保温时间为24min,65℃保温时间为71min;该优化参数下得到的麦汁α-氧基氮含量为253mg／L以上。     

外加酶对膨化大米辅料麦汁α-氨基氮含量的影响

以复合酶、糖化酶和淀粉酶用量3因素进行五水平二次旋转正交组合试验设计,研究膨化大米辅料酿造啤酒的外加酶对麦汁α-氨基氮含量的影响。得出最佳酶添加量：每50g原料添加2．5mL复合酶、2．5mL糖化酶和2．8mL淀粉酶,相应的麦汁α-氨基氮含量为155．31mg/L。     

糖化工艺参数对膨化大米辅料麦汁过滤时间的影响

以辅料含量、加水倍数、50℃蛋白质休止时间、63℃保温时间和70℃保温时间5因素进行5水平二次旋转正交组合试验设计,研究了膨化大米辅料酿造啤酒的外加酶糖化工艺参数对麦汁过滤速度的影响.结果表明,最佳糖化工艺参数为:辅料含量为45.6%～47.2%,料水比为1∶5.0～1∶5.1,50℃蛋白质休止时间为52.9～53.5 min,63℃糖化时间为43.1～44.5 min,70℃糖化时间为31.2～31.9 min.(孙悟)     

马铃薯用作啤酒辅料的糊化工艺研究

研究了马铃薯用作啤酒辅料的最佳糊化工艺。结果表明马铃薯辅料的最佳糊化条件为:1∶5的料水比,6U/g马铃薯粉的耐高温a-淀粉酶添加量,糊化温度85℃,糊化时间25min。添加马铃薯辅料所制得的麦汁符合糖化麦汁的要求,其中高含量的氨基酸是其显著特征。     

生产工艺对高辅料啤酒非生物稳定性的影响

探索了糖化方法、糖化温度、麦汁煮沸时间、麦汁pH值和PVPP添加量等生产工艺对高辅料啤酒非生物稳定性的影响.结果表明:最佳的糖化工艺条件是:采用一次煮出糖化法,糖化温度70℃,麦汁pH值为5.2～5.4,麦汁煮沸90min～100min.在啤酒中添加150mg/L的PVPP,可以明显降低啤酒中的多酚物质,提高高辅料啤酒的非生物稳定性.     

α－淀粉酶在啤酒酿造中的应用

α－淀粉酶在啤酒酿造中的应用李淑兰，张春武，孙慧酿酒，１９９４（４）：３４～３６添加α－高温淀粉酶后，使辅料大米量加大，由过去的２９％增加到３４．１％，并又添加了小麦芽，整个糖化生产过程正常，麦汁过滤时间同原工艺一样。调节糊化锅的水比为１：５，用磷酸...     

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