响应面法优化酥李果汁的酶法提取工艺

目的:研究酶解提取酥李果汁的最佳工艺条件,为李深加工利用提供理论参考。方法:以酥李出汁率为指标,在单因素实验基础上采用响应面试验优化,对单一果胶酶、单一纤维素酶、复合酶（果胶酶和纤维素酶）提取酥李果汁的工艺条件分别进行优化。结果:不同加酶方式中对酥李出汁率的影响因素顺序均为酶解温度>加酶量>酶解pH>酶解时间;果胶酶酶解提取酥李果汁的最佳工艺条件为:加酶量0.45 g/L、酶解温度38 ℃、酶解pH3.8、酶解时间72 min,出汁率提高27.13%;维素酶酶解提取酥李果汁的最佳工艺条件为:加酶量0.55 g/L、酶解温度41 ℃、酶解pH4.2、酶解时间105 min,出汁率提高20.18%;复合酶酶解提取酥李果汁的最佳工艺条件为:果胶酶添加量0.45 g/L、纤维素酶添加量0.55 g/L、酶解温度41 ℃、酶解pH4.0、酶解时间87 min,出汁率提高31.79%。三种加酶方式中,回归模型均能较好地反应相应酶制备酥李果浆的出汁率,所得工艺合理可靠。结论:在酶法提取酥李果汁过程中,果胶酶和纤维素酶的不同添加方式均能有效提高酥李出汁率,其中采用复合酶提取酥李果汁效果最佳。本研究成果为贵州李产品开发提供了一定的技术参考。     

果胶酶在拐枣果汁提取应用中的工艺优化

为提高拐枣果汁提取的出汁率,采用果胶酶酶解打浆后的拐枣果浆,研究果胶酶用于拐枣果汁提取的工艺条件。通过单因素试验,以出汁率为指标,初步确定果浆酶解时果胶酶质量分数、提取温度和作用时间的取值范围。在此基础上,通过正交试验优化提取工艺。结果表明,采用果胶酶提取拐枣果汁时,影响出汁率的因素顺序为:酶解温度对出汁率影响最大,果胶酶添加量次之,酶解时间影响最小;提取果汁的优化工艺条件为:果胶酶的质量分数0.07%,提取温度35℃,作用时间90min。在此条件下,出汁率可达50.41%,比不加酶的对照实验结果高6.07%,果汁的可溶性固形物为24%25%。因此,果胶酶可用于拐枣果汁的提取,并能增加出汁率。     

响应面法优化猕猴桃果浆酶解工艺参数研究

本文研究果胶酶反应温度和作用时间及酶用量对猕猴桃果浆出汁率、果汁澄清度和乙醇不溶物的影响,采用通用旋转设计和响应面分析猕猴桃果浆酶解最优条件。结果表明,猕猴桃果浆的最佳酶解条件为:反应温度为45℃,作用时间为113min,果胶酶用量为0.013%,在此条件下,猕猴桃果浆预测出汁率达到83.30%,乙醇不溶物0.98g/100ml,果汁的澄清度为81.47%。验证试验表明,响应面优化后得到猕猴桃果浆出汁率、果汁澄清度和乙醇不溶物回归方程的相关系数分别为0.958、0.904和0.922。     

果胶酶与半纤维素酶复合酶解制备费约果果汁的工艺优化

为减少费约果细胞壁中果胶和半纤维素等物质对果汁品质的负面影响,提高果汁出汁率,本文研究了复合酶(半纤维素酶和果胶酶)比例、加酶量、温度、时间对“Unique U-100”费约果果汁出汁率和可溶性固形物的影响。在单因素实验的基础上,进行四因素三水平的响应面优化。结果显示：在复合酶(半纤维素酶/果胶酶)比例为2.14:1,加酶量19.6 g/L,酶解温度56.8℃,酶解时间92 min的条件下,费约果果实出汁率最高,为79.5%,与模型预测值相对误差为5.67%;果汁中可溶性固形物含量为15.7%,与模型预测值相对误差为0.83%。此外,与直接压榨的费约果果汁相比,酶解后的果汁表现出更高的澄清度、总酚含量(24.4 mg GAE/100 g)和V_C含量(2.42 mg/100 g)。因此,本研究优化了复合酶酶解制备费约果果汁的工艺,提高费约果果汁出汁率和营养品质,可为后续费约果果汁深加工提供理论依据。     

酶法制备海棠果汁的酶解条件优化研究

以海棠果为原料,采用正交试验分析不同酶解条件对海棠果果汁出汁率的影响,获得最佳的酶解条件。结果显示,在果胶酶添加量为0.02%,酶解时间120 min,酶解温度45 ℃的条件下,海棠果出汁率最高,达到40%,与未加果胶酶处理的试验相比,出汁率提高了52个百分点。     

酶法液化火龙果果浆的工艺研究

本文研究了采用酶解法处理火龙果果浆的影响效果,并以火龙果果浆处理后的黏度和出汁率为指标,探讨最佳工艺条件。先进行单因素实验确定温度、时间、酶的添加量、pH值的最适取值范围,再通过试验确定单一酶和复合酶种类的最佳选择,最终使用L9(34)正交试验确定火龙果果浆液化的最佳工艺条件,并对最佳工艺条件进行验证。研究表明,在温度为50℃、时间为45 min、各种酶的添加百分含量为0.07%、pH值为4.3的条件下,用果胶酶、纤维素酶和半纤维素酶组成的复合酶处理新鲜火龙果果浆为最佳的工艺条件,处理后的火龙果果浆黏度大幅下降,出汁率明显提高,黏度较空白对照下降170.5 mPa·s,出汁率提高14.8%,且色泽口感保持良好,且作为调配饮料原料酸度在可接受范围内。     

酶解对枸杞果出汁率的影响

以宁夏枸杞鲜果为原料,经打浆与护色后,用不同酶制剂进行酶解处理,结合酶量、反应温度、反应时间及底物p H,考察对枸杞出汁率和可溶性固形物的影响。经单因素和Box-Behnken优化实验,确定枸杞浆最佳酶解工艺。实验确定的果胶酶酶解最优条件为:果胶酶添加量0.016%,温度41℃,酶解时间1.3 h,枸杞浆出汁率为48.75%。复合酶酶解最优条件为:复合酶(果胶酶∶纤维素酶=3∶7)添加量0.09%,酶解温度35℃,酶解时间2.7 h,枸杞浆出汁率为49.20%。且两种酶对可溶性固形物无显著性影响(p0.05)。结果表明:果胶酶及复合酶均能大幅度提高枸杞果的出汁率,但复合酶比单一果胶酶对提高枸杞果出汁率效果更好。     

浑浊型光皮木瓜果汁的配方优化

以新鲜的光皮木瓜为原料,将取汁后的果渣经酶解、打浆后再利用,来提高果汁的感官品质。通过正交试验对果渣酶解工艺进行优化,采用模糊数学感官评价法优化浑浊型果汁配方。结果表明,果胶酶与纤维素酶按质量比1∶1混合添加,添加量0.022 g/L,于pH 4.0、35℃条件下酶解60 min,出汁率可达（28.45±0.62）%;果渣酶解打浆后,浆液添加量为7%,将白砂糖与果葡糖浆按质量比1∶3、总添加量1.6 g/L进行调配,可明显改善果汁口感。     

响应面法优化柿子果汁的酶解工艺研究

本文研究了柿子果汁的酶解工艺。通过单因素试验分别考察了酶解时间、酶解温度和酶添加量对柿子果汁出汁率的影响,并利用响应面分析法优化了柿子果汁酶解的最佳工艺条件。结果表明：柿子汁最佳酶解条件为：酶解温度55℃、酶添加量56U/g、酶解时间109min。     

果胶酶对番石榴出汁率的影响

为探索果胶酶对番石榴果浆的出汁率的影响,以廉江本地番石榴为试材,采用单一果胶酶酶解方法,研究果胶酶添加量、酶解温度及酶解时间三个因素对番石榴出汁率的影响。结果表明,酶解的最佳工艺为:酶添加量0.05%、酶解时间4 h、酶解温度为45℃。在此基础上进行验证试验,测得番石榴出汁率为81.54%,相比于未加果胶酶处理的空白试验,番石榴的出汁率提高了13.78%。     

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