响应面法优化玫瑰花酱无硫护色剂配方

为解决传统玫瑰花酱在加工过程中极易发生褐变的问题,选取护色剂柠檬酸、苹果酸、抗坏血酸、氯化钠和L-半胱氨酸作为自变量,以玫瑰花酱的褐变度为响应值,进行响应面分析及采用模糊数学感官评价法研究护色剂对玫瑰花酱品质的影响。结果表明,抗坏血酸和L-半胱氨酸对玫瑰花酱没有护色效果,柠檬酸、苹果酸和氯化钠对玫瑰花酱有护色效果,复合护色剂的最优配方为0.16%柠檬酸、0.16%苹果酸和0.31%氯化钠,在此条件下,加工的玫瑰花酱护色效果好,玫瑰花酱感官评得分最高。     

响应曲面法优化花生芽菜护色剂配方

以花生芽菜为原料,选取三种护色剂氯化钠、柠檬酸及抗坏血酸进行护色试验。单因素试验结果表明三种护色剂均对花生芽菜具有良好的护色效果。在单因素试验基础上,采用响应曲面法,以褐变抑制率为评价指标,分析不同护色剂配方对花生芽菜褐变抑制率的影响。结果表明:三种护色剂对花生芽菜褐变抑制率的影响顺序为抗坏血酸>氯化钠>柠檬酸,最佳配方为氯化钠0.31g/100mL、柠檬酸0.93g/100mL、抗坏血酸0.57g/100mL,在此条件下褐变抑制率为73.13%。     

杏鲍菇片干制的非硫护色剂研究

为解决杏鲍菇片干制过程中的褐变问题,采用新鲜杏鲍菇为原料,以L*值为评价指标,通过单因素试验法研究了柠檬酸亚锡二钠、柠檬酸、抗坏血酸、EDTA-2Na、Na Cl、CaCl_2、焦亚硫酸钠7种护色剂对杏鲍菇片的护色效果,并通过正交试验筛选了非硫护色剂的最优组合。结果表明:不同护色剂对杏鲍菇片的褐变均有一定的抑制作用,其中柠檬酸亚锡二钠、柠檬酸、EDTA-2Na和抗坏血酸的护色效果较好,均优于焦亚硫酸钠;非硫复合护色剂的最优组合为:柠檬酸亚锡二钠0.012%、柠檬酸0.3%、EDTA-2Na0.4%、抗坏血酸0.025%,因素主次顺序为:柠檬酸抗坏血酸柠檬酸亚锡二钠EDTA-2Na。经验证,最优参数组合的L*值为80.10±0.07。     

双孢菇干制的非硫护色剂研究

为解决双孢菇干制过程中的褐变问题,选用柠檬酸、氯化钙、氯化钠、抗坏血酸、乙二胺四乙酸二钠、L-半胱氨酸和六偏磷酸钠7种护色剂对双孢菇进行护色处理。单因素实验表明:不同护色剂对双孢菇褐变都有一定的抑制作用,其中氯化钙、抗坏血酸、L-半胱氨酸和六偏磷酸钠护色效果明显。通过响应面优化实验得出非硫复合护色剂的最佳组合为:抗坏血酸0.053%,L-半胱氨酸0.021%,六偏磷酸钠0.047%,氯化钙0.061%。该复合护色剂重复使用25次仍有很好的护色效果。     

柠檬酸亚锡二钠对双孢菇罐头的护色作用

研究柠檬酸亚锡二钠(DSC)对双孢菇罐头的护色作用。在双孢菇切片预处理和罐头汤汁中添加DSC与其他常用护色剂及其正交复合护色剂,测定产品的PPO残余酶活和褐变度BD等质量指标。在预处理阶段,较之植酸、柠檬酸、VC,DSC对双孢菇酶促褐变有更佳的抑制作用,预煮前以最佳复合护色剂(质量分数)0.2%柠檬酸,0.03%DSC,0.02%植酸,0.03%VC护色液浸泡预处理可有效防止菇片褐变;DSC用于双孢菇罐头汤汁比其他护色剂有更显著的褐变抑制效果,汤汁复合护色剂的最佳参数组合为(质量分数):0.03%DSC,0.02%植酸,0.3%CaCl2和0.1%柠檬酸,各因素对其影响程度为:DSC>植酸>氯化钙。DSC复合护色剂可有效抑制双孢菇罐头褐变,效果可与焦亚硫酸钠媲美,可作为蘑菇罐头中替代焦亚硫酸钠的新型安全高效护色剂。     

鲜切莴苣护色处理的试验研究

研究贮藏条件及抗坏血酸、植酸和柠檬酸等护色剂对鲜切莴苣色泽变化的影响。结果表明,真空冷藏可较好地抑制酶促褐变,把鲜切莴苣片置入0.05%抗坏血酸、0.25%植酸、0.05%柠檬酸和0.5%氯化钙组成的复合护色液中,浸泡5min可有效护色,护色时间可达5d。     

全藕粉生产过程中护色技术的研究

在全藕粉的生产过程中,通过单因素实验和正交实验确定防止鲜切藕片褐变的护色剂组合。研究结果表明:当护色液组成为柠檬酸0.15%,抗坏血酸0.15%,DL-苹果酸0.25%,L-半胱氨酸0.15%时,其护色效果优于护色效果较好的含硫护色剂,而组合护色剂不含硫,对人体无害,更符合现代食品安全的要求。     

川明参无硫护色工艺

为解决川明参加工处理后产生的褐变问题,采用新鲜川明参为原料,以L*、b*值及褐变度为评价指标,通过单因素试验研究柠檬酸、氯化钙、氯化钠、L-半胱氨酸、抗坏血酸5种不同浓度的护色剂对川明参的护色效果,通过正交试验筛选适宜川明参加工的护色剂种类及添加量。结果表明,单一护色剂中柠檬酸、氯化钙、氯化钠护色效果较好;川明参在最佳复合护色剂柠檬酸浓度0.5%,氯化钙浓度0.2%,氯化钠浓度1.6%中浸泡60 min,所得L*值为62.03, b*值为18.20,褐变度为0.135。     

响应曲面法优化鲜青花椒护色剂配方

以新鲜青花椒为原料,选取碳酸钠、葡萄糖酸锌、柠檬酸、抗坏血酸4种护色剂进行不同浓度梯度的鲜青花椒护色的单因素试验;选择对青花椒褐变度和叶绿素含量效果较好的3种护色剂及不同浓度,以褐变度为指标,采用响应曲面法研究对鲜青花椒护色效果最好的护色剂复配配方。单因素试验结果表明:研究选取的葡萄糖酸锌、柠檬酸和抗坏血酸浓度均对青花椒褐变度和叶绿素含量产生显著影响(P0.05);同时,响应面试验结果表明,各因素对鲜青花椒褐变度的影响顺序为:柠檬酸葡萄糖酸锌抗坏血酸;最优的护色剂配方为:葡萄糖酸锌0.07%,柠檬酸0.46%,抗坏血酸0.69%,在此条件下,鲜青花椒的褐变度为5.88,与对照组相比降低6左右,说明此护色剂配方可有效降低鲜青花椒的褐变度。     

褐变抑制剂对干制香蕉片护色效果的影响

为了提高香蕉片干制后的颜色品质,获得最佳护色方法,以褐变度和L*值为考察指标,研究植酸、抗坏血酸、氯化钠、EDTA、柠檬酸5种褐变抑制剂对干制香蕉片颜色品质影响,并优选出提高干制香蕉片颜色品质的护色方法。结果表明:单一护色剂护色效果依次为植酸柠檬酸EDTA氯化钠抗坏血酸,将鲜切香蕉片放入植酸(质量分数为0.9%)和柠檬酸(质量分数为0.3%)组成的复合护色液中浸泡20 min,干制后的香蕉片L*值达65.93,褐变抑制率达84.4%。     

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