姜辣素的酶法提取及其对亚硝酸盐清除的研究

以生姜为原料,采用酶解法辅助乙醇提取生姜中的姜辣素,以酶解时间、酶解温度、纤维素酶的添加量以及料液比为自变量,以姜辣素提取率为试验指标,通过正交试验确定酶解法提取生姜中姜辣素的最佳工艺条件为酶解时间90 min、酶解温度50℃、纤维素酶添加量0.95%、料液比为1∶50(g/m L)。在最优工艺条件下生姜中的姜辣素提取率最高达到1.85%。提取得到的姜辣素粗提物可用于清除亚硝酸盐,通过正交试验得到姜辣素粗提物清除亚硝酸盐的最优反应条件为:反应体系温度100℃、反应时间15 min、姜辣素粗提物质量浓度为17.5 mg/m L。在该反应条件下姜辣素粗提物对亚硝酸盐的清除率可达(99.32±0.22)%,与1 mg/m L同体积的抗坏血酸溶液对亚硝酸盐的清除能力相当。     

纤维素酶-超声辅助提取姜辣素的工艺优化

为了获得一种得率较高的姜辣素提取方法,以生姜为原料,姜辣素提取率为指标,应用纤维素酶与超声结合法从生姜中提取姜辣素。首先研究酶解温度、酶解时间、酶解pH、超声时间、超声温度、超声功率等因素对姜辣素提取率的影响,在此基础上,通过响应面中心组合试验设计对生姜中姜辣素的提取工艺进行优化,并建立相应的回归方程。获得最佳工艺条件为酶解温度47℃,酶解时间61min,酶解pH 5.9,超声温度49℃。通过3次验证试验,实际测得姜辣素的提取率为4.7701%,与理论预测值相对误差为-0.0587%,为生姜的开发利用提供理论依据。     

混料设计优化复合酶水解水酶法提取大豆油工艺

利用混料优化设计对最适合水酶法提取大豆油脂的复合酶配比条件和水解条件进行优化,以总油提取率为指标,确定复合酶水解的水酶法提取大豆油脂和蛋白工艺最优条件。结果表明,料水比1:6(g/mL)、纤维素酶添加量0.84%、半纤维素酶添加量0.56%、酶解pH5、酶解温度37℃条件下水解0.75h后,再利用Alcalase碱性内切蛋白酶,加酶量1.85%、酶解温度50℃、酶解pH9.26、水解3.6h,总油提取率达到极大值即81.04%,比以往国内研究采用湿热处理工艺有很大提高。     

酶促法提取油菜籽皮中的原花青素研究

研究采用纤维素酶、半纤维素酶和果胶酶共同酶解油菜籽皮干粉提取原花青素。以原花青素提取质量比为指标,通过单因素试验,确定原花青素的最优提取工艺。结果表明酶促反应的最佳反应体系:纤维素酶、半纤维素酶和果胶酶配比30∶7∶6,复合酶用量40U/g,酶解pH 5.0、酶解温度55℃、酶解时间120min。验证实验表明酶促法油菜籽皮原花青素的提取质量比为3.59mg/g,比普通溶剂法提取质量比提高了66.98%。采用酶促法可以较高程度地提高油菜籽皮原花青素的提取质量比。     

响应面优化超声-酶辅助强化油橄榄叶多糖的提取

以油橄榄叶为原料,采用超声-酶辅助法强化其中多糖的提取,通过单因素实验和响应面实验对提取条件进行了优化。同时,采用扫描电镜(SEM)对提取多糖后的物料结构形态进行了观察。结果表明,采用先酶解后超声的提取方式效果较好,优化的提取工艺条件为:纤维素酶与果胶酶质量比2∶1,酶添加量0. 6%,液料比40∶1,酶解温度54℃,酶解时间3 h,超声体积功率密度120W/L,超声时间19 min。在最优条件下,油橄榄叶多糖提取率为4. 50%。SEM观察表明,超声-酶辅助提取过程可以破坏油橄榄叶细胞壁结构,从而减小提取过程的传质阻力,提高多糖提取率。     

复合酶水酶法提取大豆蛋白的工艺优化

采用复合酶水酶法提取大豆蛋白。水解酶选用碱性蛋白酶,复合酶采用纤维酶、半纤维酶、果胶酶。得出最优复合酶水酶法提取大豆蛋白工艺条件为料水比1:6(g/mL)、纤维素酶添加量0.64%、半纤维素酶添加量0.56%、酶解pH5、酶解温度37℃条件下水解0.75h后,再利用Alcalase碱性内切蛋白酶,加酶量1.85%、酶解温度50℃、酶解pH9.26、水解3.6h。经过验证实验可知,在最优酶解工艺条件下总蛋白提取率可达到极大值即85.78%。经过复合酶酶解预处理比传统的湿热预处理的总蛋白提取率提高了近10%,其原因经分析是经过复合酶酶解处理的豆粉其细胞结构充分破坏,使得酶的作用位点暴露更有利于蛋白酶的作用,具体的机理分析有待进一步研究。     

灵芝多糖的复合酶法提取工艺优化

以灵芝子实体为原料,采用复合酶法(纤维素酶、半纤维素酶、木瓜蛋白酶)提取灵芝多糖,并分析工艺条件对多糖提取率的影响。在正交试验确定复合酶比例的基础上,采用响应面法对复合酶法提取灵芝多糖的提取条件进行了优化,得到最优工艺条件。研究结果表明,复合酶比例为:纤维素酶3.5%、半纤维素酶4.0%、木瓜蛋白酶3.0%;最佳酶解提取条件为:酶解处理pH值、温度和时间分别为5.70、50℃和81 min,在此条件下灵芝多糖的提取率为3.73%。     

超声辅助酶解-索氏提取联用法提取马齿苋籽油及其脂肪酸组成分析

为提高马齿苋籽油的提取率和油品品质,以马齿苋籽油提取率及理化性质为指标,利用超声辅助酶解法预处理马齿苋籽,采用索氏提取法提取马齿苋籽油,并在单因素试验基础上采用正交试验确定酶解法预处理的最优条件。利用气相色谱/质谱联用仪(GC-MS)对超声辅助酶解-索氏提取联用法和传统索氏提取法制备的马齿苋籽油脂肪酸成分进行分析并比较。结果表明:酶解法预处理的最优工艺条件是加酶量2.0%,酶解温度50℃,酶解pH 6.0,液固比(mL∶g)6∶1,此条件下马齿苋籽油提取率可达86.8%,与传统索氏提取法相比提高了15.43%。两种方法所得的马齿苋籽油中均含有多种不饱和脂肪酸,且不饱和脂肪酸含量均大于85%,其中亚麻酸含量大于39%。     

不同酶处理对小麦胚芽油提取率的影响

研究不同酶处理对小麦胚芽油提取率的影响,确定最佳水酶法提取小麦胚芽油工艺。选用纤维素酶、半纤维酶、酸性蛋白酶、淀粉酶、果胶酶作为提取酶,对小麦胚芽进行酶解,研究了不同酶处理对提油率的影响。单一酶处理试验中,分别用纤维素酶和酸性蛋白酶处理的提油率较高;复合酶处理试验中,酸性蛋白酶和纤维素酶组合处理的提油率最高;且复合酶处理比单一酶处理的提油率高。经过正交试验得出小麦胚芽油水酶法最优提取工艺为:复合酶(酸性蛋白酶∶纤维素酶=5∶1),酶解pH=5,酶解温度45℃。经验证试验小麦胚芽提油率可达到65.53%。试验提取的小麦胚芽油不饱和脂肪酸含量高达82%以上,营养品质较好。     

混料设计优化水酶法提取西瓜籽油的工艺研究

以西瓜籽为原料,研究水酶法提取西瓜籽油的最优工艺并对其脂肪酸组成、理化特性进行分析。在单因素实验基础上,采用混料设计对复合酶不同配比进行优化。得到的最优分步酶解条件为:首先采用复合酶(纤维素酶、果胶酶、半纤维素酶)配比0.68∶0.22∶0.10,复合酶添加量2.0%,在p H 5.0、酶解温度50℃、液料比7∶1条件下酶解2 h;然后加入1.5%的碱性蛋白酶,在p H 7.5、酶解温度55℃条件下继续酶解2 h。在最优分步酶解条件下,西瓜籽油提取率为91.45%。所得西瓜籽油色泽淡黄,澄清透明,富含不饱和脂肪酸,其理化指标符合国家食用油卫生标准。     

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