响应面优化蒲公英多酚超声波辅助乙醇提取工艺及其抗氧化性

本实验以蒲公英全草为原料,选取超声波提取时间、超声波功率、料液比、超声提取温度四个因素为自变量,结合单因素实验结果,对蒲公英多酚超声波辅助提取工艺进行优化,最后对蒲公英不同部位多酚抗氧化活性进行评估。结果表明:四因素对提取率的影响大小依次是提取温度超声波功率超声提取时间料液比;超声波辅助乙醇提取蒲公英多酚的最佳工艺条件为提取时间37 min、超声功率380 W、提料液比1∶48、温度42℃,多酚平均提取率为3.68%±0.05%,与理论预测值3.72%误差值仅为0.94%。在优化条件下依次对蒲公英全草、叶片和根中的多酚进行提取并比较其抗氧化活性,三者均具有较强的抗氧化能力,蒲公英不同部位的抗氧化活性大小依次为蒲公英叶片蒲公英全草蒲公英根。     

超声辅助纤维素酶法提取玉米皮总多酚及其抗氧化性研究

以脱脂玉米皮为原料,优化超声辅助酶法提取玉米皮总多酚工艺,并对其抗氧化性进行体外研究。在单因素实验基础上,采用Box-Behnken响应面设计法,以总多酚提取量为响应值,对超声时间、酶解温度、酶加入量和液料比参数进行优化。确定玉米皮总多酚的最佳提取工艺为:超声时间7.5 min,酶解温度50℃,纤维素酶加入量4.20%,液料比39 mL/g。此条件下,脱脂玉米皮总多酚提取量为(5.46±0.15)mg/g,该法所得的提取工艺参数可靠,可为玉米皮的开发利用提供参考。采用DPPH·和ABTS+·清除法对玉米皮总多酚进行体外抗氧化实验,结果表明玉米皮多酚具有较强的抗氧化能力,可作为潜在天然抗氧化剂应用于食品行业。     

两种技术联用优化刺玫果多酚提取工艺及体外抗氧化活性研究

目的优化刺玫果多酚的提取工艺并探讨其体外抗氧化活性。方法采用超声波辅助酶解法,通过正交试验考察纤维素酶用量、乙醇体积分数、酶解温度、超声时间对刺玫果多酚提取得率的影响;通过测定刺玫果多酚对DPPH、ABTS自由基的清除能力及总抗氧化活性来评价刺玫果多酚的体外抗氧化活性。结果影响刺玫果多酚提取率的因素顺序是超声时间>纤维素酶用量>酶解温度>乙醇体积分数,提取刺玫果多酚最佳的工艺条件为纤维素酶用量1.5%,乙醇体积分数为55%,酶解温度为50℃,超声时间为25min。3次重复实验,刺玫果多酚提取率为183.15mg/g;刺玫果多酚质量浓度为8.67mg/mL时,对DPPH自由基的清除率为89.70%,对ABTS自由基的清除率为90.85%,总抗氧化活性能力强。结论刺玫果多酚具有较好的抗氧化活性,在天然的抗氧化活性剂与自由基清除剂方面可以进一步开发与应用。     

响应面法优化水酶法提取松子蛋白的研究

主要研究了水酶法提取松子蛋白的酶解工艺。选用Alcalase碱性蛋白酶作为水解酶,以总蛋白提取率为指标。通过单因素实验和响应面实验,得到影响实验的因素依次为加酶量>酶解温度>料液比>酶解pH>酶解时间。确定最佳的酶解参数为:加酶量1.9%,温度55℃,酶解时间2.2h,料液比1∶5,pH8.8,此时总蛋白提取率为87.92%。     

酶解-超声辅助联用提取塔尔米多糖

以生塔尔米粉为原料,分别采用超声辅助法、酶解-超声辅助联用提取塔尔米多糖,考查了酶解工艺对塔尔米多糖提取效果的影响,同时采用总抗氧化能力、DPPH·自由基和ABTS~+·自由基清除能力评价了塔尔米多糖的抗氧化活性。以提取率和纯度为考察指标,通过单因素实验和U_(10)(10~6)均匀设计实验优化超声辅助法工艺参数,采用L_9(3~4)正交实验优化酶解工艺。结果表明,酶解-超声辅助联用提取塔尔米多糖的最优工艺为:液料比20:1,酶解pH6.5,酶解温度50℃,酶解时间30 min,超声温度40℃,超声时间20 min,超声功率160W,塔尔米多糖提取率为5.24%,纯度64.32%。酶解处理显著提高了塔尔米多糖的提取效果,塔尔米多糖有一定的抗氧化能力,且呈量效关系。     

白花丹参多糖酶法提取条件的响应面优化及其抗氧化活性研究

研究响应面优化复合酶法提取白花丹参多糖的工艺,并评价其抗氧化活性。以白花丹参多糖提取率为响应值,液料比、酶解温度、酶解时间、复合酶(木瓜蛋白酶:纤维素酶:果胶酶=2:2:1)添加量为实验因素,采用响应面法建立数学模型,优化提取条件,并初步探讨白花丹参多糖的理化性质,考察白花丹参多糖对DPPH和·OH自由基的清除能力。结果表明,通过二次回归模型响应面分析,液料比、酶解时间、温度、复合酶添加量四因素对白花丹参多糖提取率的影响依次减弱;最佳工艺条件为酶解温度52℃、时间70 min、复合酶添加量8.0 mg/mL、液料比例为45:1 mL/g,在此条件下多糖提取率为13.36%,模型方程理论预测值为13.70%,两者相对误差小于5%。白花丹参多糖为左旋型、酸性多糖,易溶于水,并具有较强的抗氧化活性,对DPPH和·OH自由基的半数抑制浓度分别为0.969 mg/mL和3.114 mg/mL,但抗氧化活性小于VC。采用响应面法优化得到了白花丹参多糖的最佳复合酶提取工艺,得到的多糖具有较强的抗氧化活性。     

复合植物水解酶提取花生油脂体工艺研究

为了提高花生油脂体的提取率,选用复合植物水解酶辅助提取花生油脂体。通过单因素实验考察了料液比、酶用量、酶解时间、酶解温度对复合植物水解酶提取花生油脂体提取率的影响。在单因素实验的基础上,采用正交试验对复合植物水解酶提取花生油脂体的工艺进行优化。实验结果表明,在所选取的参数范围内,各因素对花生油脂体提取率的影响由大到小为:料液比、酶解温度、酶解时间、酶用量。获得其较佳工艺条件为料液比1:4(g/mL)、酶用量1.25%、酶解时间80min、酶解温度50℃,在该条件下花生油脂体提取率为48.92%。     

神秘果种子多酚超声双水相复合提取工艺及其抗氧化活性

利用超声波与双水相体系复合提取神秘果种子多酚,研究不同条件下提取的多酚的抗氧化能力。分别考察丙酮浓度、硫酸铵用量、超声波温度、超声波时间、料液比对神秘果种子多酚提取率的影响;采用单因素试验及响应面设计,优化神秘果种子多酚提取工艺。结果表明,最佳提取工艺条件为:丙酮浓度50%、硫酸铵用量0.22g、超声波温度60℃、超声波时间100min、液料比1∶20(m∶V),多酚理论提取率为11.54%。该条件下神秘果种子多酚的平均提取率为11.56%。该体系提取的多酚纯度为87.85%,优于单独采用超声波提取,可实现初步纯化。抗氧化性试验结果表明,神秘果种子多酚提取物对DPPH·的清除能力和还原能力较强,且还原力和DPPH·清除率与总多酚含量呈正比关系;其抗氧化活性强于抗坏血酸。     

石吊兰总多酚体外抗氧化活性研究

研究石吊兰总多酚的体外抗氧化活性。采用单因素实验研究提取时间、超声波功率、提取温度、乙醇浓度、提取次数和料液比对总多酚提取率的影响。用还原能力、·OH清除率、DPPH·清除率来考察石吊兰总多酚的体外抗氧化活性。结果表明,超声提取石吊兰总多酚的最佳工艺条件为:提取时间32min,超声波功率为100%,提取温度为25℃,乙醇浓度为80%,提取次数为3次,液料比为20∶1,此时石吊兰总多酚得率为14.0mg GAE/g。此外,石吊兰总多酚的还原能力、对·OH以及DPPH·的清除均高于VC。石吊兰总多酚是天然的抗氧化活性剂和自由基清除剂。     

猕猴桃可溶性膳食纤维酶法制备工艺及抗氧化活性研究

以猕猴桃皮渣为原料,采用酶法制备猕猴桃可溶性膳食纤维。在单因素实验的基础上,以纤维素酶添加量、酶解时间、酶解温度和液料比为实验因素,以可溶性膳食纤维提取率为响应值,采用四因素五水平的响应面分析法进行实验,优化提取工艺参数。同时,考察了猕猴桃可溶性膳食纤维对DPPH和ABTS+自由基的清除效果及其还原能力。结果表明,酶法制备猕猴桃可溶性膳食纤维的最佳工艺条件为:酶添加量0.86%、酶解时间2.5h、酶解温度62℃和液料比27∶1(mL/g),在该条件下猕猴桃可溶性膳食纤维提取率预测值为13.379%,验证值为12.983%,响应面法对猕猴桃可溶性膳食纤维提取条件的优化是可行的,可用于实际预测。抗氧化活性实验表明猕猴桃可溶性膳食纤维具有较强的自由基清除效果和还原能力,对DPPH和ABTS+自由基的EC50分别为4.68mg/mL和1.28mg/mL。     

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