甲醇-乙醇混合溶剂萃取脱酚制备脱酚棉籽蛋白的工艺研究

以脱脂棉籽湿粕为原料,利用甲醇-乙醇混合溶剂萃取脱酚制备脱酚棉籽蛋白,通过单因素试验和正交试验重点探讨了甲醇-乙醇混合比例、混合溶剂体积分数、萃取温度、萃取时间和料液比对脱酚棉籽蛋白游离棉酚含量和蛋白质氢氧化钾溶解度的影响。确定的最佳工艺条件为:甲醇-乙醇混合比例1∶1(质量比),甲醇-乙醇混合溶剂体积分数90%,萃取温度55℃,每次萃取时间25 min,料液比1∶3,分3次进行。在最佳工艺条件下制备的脱酚棉籽蛋白游离棉酚含量为157mg/kg,蛋白质氢氧化钾溶解度为62.7%。     

棉籽粕脱酚效果影响因素分析

为了降低棉籽粕中游离棉酚含量，通过实验室及生产线跟踪研究了溶剂萃取法脱酚工艺参数、脱酚方法(膨化预处理法、溶剂萃取法)、原料产地和储存时间对棉籽粕脱酚效果的影响。结果表明：工业生产中，在棉坯粉末度25%～28%、棉坯水分含量3.5%～4.5%、甲醇体积分数85%～90%、脱酚温度55℃左右、逆流萃取脱酚料液比(物料质量与新鲜甲醇溶剂体积比) 1∶(0.5～0.6)条件下，棉籽粕脱酚效果较好；溶剂萃取法脱酚效果优于膨化预处理法；对于棉籽原料产地，棉酚的脱除容易程度为北疆>南疆>河北，与棉籽的粗脂肪酸值大小正好相反；棉籽储存时间越长，棉酚越难以脱除。因此，选择新鲜、粗脂肪酸值低的棉籽原料，严格控制溶剂萃取脱酚工艺参数，可以得到更低游离棉酚含量的棉籽粕。     

响应面法优化超声辅助竹叶鸡爪茶多酚的提取工艺

目的 采用响应面法优化竹叶鸡爪茶多酚的超声提取工艺。 方法 通过超声辅助法提取竹叶鸡爪茶中的总酚, 以总酚含量为评价指标, 考察超声温度、超声功率、超声时间、乙醇浓度、液料比5个因素对总酚含量的影响, 选择4个因素(超声温度、超声时间、乙醇浓度、液料比)设计4因素3水平Box-Behnken响应面试验进行工艺优化。结果 竹叶鸡爪茶多酚的最佳提取工艺为: 超声温度71 ℃、超声时间35 min、液料比42:1 (V:m)、乙醇浓度57%, 此条件下测得的多酚含量(2.33±0.01) mg/g, 与预测值2.37 mg/g接近, 相对误差为1.68%, 表明模型预测值与实际值基本吻合。结论 超声辅助提取法能够有效地提取竹叶鸡爪茶多酚。     

超声辅助提取木瓜皮中结合酚的工艺研究

利用响应面法优化超声辅助提取木瓜皮中结合酚的水解工艺。基于单因素试验,考察盐酸浓度、料液比、水解时间和水解温度对结合酚水解率的影响,选取料液比、水解时间和水解温度为随机因子,采用响应面法优化结合酚水解条件。结果表明结合酚水解的最优条件HCl 0.20 mol/L,料液比1︰8.22(g/m L),水解时间36.92 min,水解温度46.40℃。在此条件下结合酚水解率的预测值为96.02%,实际验证值为96.11%,二者相差较小,说明该优化方法对于木瓜皮中结合酚的水解是可行的。提取木瓜皮中的结合酚对于植物总酚的精确提取与木瓜的进一步利用具有重要意义。     

棉仁低温压榨饼己烷/甲醇分步浸出工艺研究

以棉仁低温压榨饼为原料,采用己烷浸出脱脂,然后用甲醇浸出脱除棉酚,制备棉籽蛋白粉.以粕中残油率、游离棉酚含量为考察指标,通过单因素实验和正交实验,确定己烷脱脂最佳浸出工艺条件为:浸出温度55 ℃,原料粒度0.75 cm,水分9%以下,料液比1∶1.2,浸出次数8次(每次15 min);甲醇脱酚最佳浸出工艺条件为:浸出温度60 ℃,粒度0.75 cm,料液比1∶1.3,浸出次数6次(每次15 min).在最佳脱脂脱酚工艺条件下,制得棉籽蛋白粉,其残油率为0.52%,游离棉酚含量为250 mg/kg,粗蛋白含量达到52.10%(N×6.25,干基).     

棉籽蛋白提取工艺研究

以脱酚无毒棉籽粕为原料提取蛋白,研究了料液比(W/V)、pH、提取温度、提取时间对棉籽蛋白提取率的影响.在单因素实验分析基础上,进行了正交实验,对相关因素在不同水平上对结果的影响进行了分析.结合考虑实际操作的可行性,最终确定棉籽蛋白质最佳提取工艺条件为:料液比1:25(W/V),提取液pH为11.5,50℃条件下浸提2h.蛋白质提取率达到83.40%,蛋白质纯度为94.91%.     

响应面法优化超声提取苦参中总酚工艺

利用Design-Expert 7.1.6软件Box-Benhnken中心组合试验和响应面分析法优化苦参中总酚的提取工艺条件。在单因素试验的基础上,考察乙醇浓度、超声时间、液料比和超声温度的单一和交互因素对苦参提取率的影响。结果表明:苦参总酚的最佳提取工艺为乙醇浓度44.20%、超声时间29.50 min、液料比32.50∶1(m L/g)、超声温度57.00℃,在此条件下苦参总酚提取率可达4.51%。     

棉籽浓缩蛋白制备及其物理改性工艺研究

以低温脱溶棉籽粕为原料,选用乙醇洗涤法制备棉籽浓缩蛋白。考察了乙醇体积分数,醇洗温度,醇洗时间,醇洗次数,料液比对棉籽浓缩蛋白产品蛋白质含量的影响。得到的最佳工艺条件为:乙醇体积分数70%,醇洗温度50℃,醇洗3次(每次20 min),料液比1∶7;在最佳工艺条件下,制得棉籽浓缩蛋白产品蛋白质含量为68.25%(N×6.25,干基),游离棉酚含量下降到0.035 4%。为提高产品的溶解性,对醇洗棉籽浓缩蛋白进行物理改性研究,探讨了热水温度,捣碎均质时间,蛋白质溶液p H,超声波处理时间对产品溶解性的影响。得到的最佳工艺条件为:热水温度95℃,捣碎均质时间10 min,蛋白质溶液p H 9,超声波处理时间15 min;在最佳工艺条件下,制得的改性棉籽浓缩蛋白产品NSI由12.30%上升到26.59%,且高于原料棉籽粕的24.46%。     

超声辅助提取花生粕中植酸工艺优化

用响应面法研究超声波辅助提取花生粕中植酸的最佳工艺,考察超声温度、超声时间、超声功率、液料比和盐酸浓度5 个因素对植酸提取率的影响。经响应面优化的超声波辅助提取植酸的优化工艺条件：超声温度40℃、超声时间24min、超声功率72W、液料比11:1(mL/g)、盐酸浓度0.01mol/L,此时提取率为1.48%,与模型预测值1.44% 相差不到3%。实验结果说明超声波方法可较好地应用于花生粕中植酸的提取,同时得到一个能较好预测实验结果的提取模型方程。     

超声波辅助碱提香菇柄中水溶性蛋白的工艺

以蛋白质得率为指标,研究液料比、pH、超声功率、超声温度及超声时间对蛋白质得率的影响,在单因素基础上,选取液料比、超声温度及超声时间为自变量,利用响应曲面法对超声波辅助碱提香菇柄中水溶性蛋白的提取工艺进行优化。结果表明,超声辅助碱提香菇柄中水溶性蛋白的最佳提取工艺条件为:液料比值16.8 mL/g,超声温度45.3℃,超声时间46.4 min。在此条件下,蛋白质得率达到2.87%。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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