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。     

超声波辅助提取霍山石斛多糖及其抗氧化活性研究

以霍山石斛为原料,利用超声波辅助法提取霍山石斛多糖,采用Box-Behnken设计和响应面分析对提取条件进行优化,同时比较了超声波辅助提取工艺和热水浸提工艺所得霍山石斛多糖的还原力和ABTS自由基清除率。结果表明,超声波辅助提取霍山石斛多糖的最优工艺条件为:液料比30:1,浸提温度81℃,浸提时间120 min,超声功率423 W,超声时间8 min,在此优化条件下多糖平均得率为19.96 mg/g,是传统热水浸提工艺的1.70倍。体外抗氧化结果显示,超声波辅助提取工艺所得霍山石斛多糖还原力和ABTS自由基清除率均优于热水浸提的多糖。该试验结果为后续霍山石斛多糖的提取和抗氧化活性研究提供了实验依据和技术支持。     

超声辅助提取苦荞芽多酚及其抗氧化活性分析

优化了超声波辅助提取苦荞芽中多酚类物质的工艺条件,并采用ABTS和DPPH自由基清除率法检测了苦荞芽多酚提取物的抗氧化活性。研究结果表明,苦荞芽多酚的最佳提取条件为:甲醇体积分数60%、超声时间30 min、超声温度50℃、料液比1:50 g/mL,在该条件下苦荞芽多酚的提取量可达72.82 mg/g。抗氧化活性测定结果表明,苦荞芽多酚提取物对ABTS自由基和DPPH自由基均有较强的清除能力,其半抑制浓度(IC50)值分别为119.26、205.24μg/mL。     

牛蒡多酚超声辅助酶法提取工艺及抗氧化活性

研究了牛蒡多酚的超声辅助酶法提取工艺及抗氧化活性。在单因素试验基础上,通过响应面分析法优化牛蒡多酚的提取工艺,并检测提取物对1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基、超氧阴离子自由基、羟自由基的清除能力。结果表明:牛蒡多酚的最佳提取条件为乙醇体积分数45%、液料体积质量比为20 mL/g、超声时间6 min、纤维素酶质量浓度1.25 mg/mL、酶解时间80 min、酶解温度50℃,此条件下多酚的提取率为41.33 mg/g,比超声波辅助法和纤维素酶法分别提高了39.30%、25.13%。所提多酚具有较强的抗氧化活性,且在一定质量浓度范围内,多酚的抗氧化能力与其质量浓度呈现一定的剂量效应关系,0.5 mg/mL的多酚溶液对DPPH自由基的清除率达55.66%,接近同质量浓度VC对DPPH自由基的清除率。     

基于RSM法优化黑果腺肋花楸多酚提取工艺及抗氧化活性研究

确定了黑果腺肋花楸多酚的最佳提取工艺,并测定其抗氧化活性。以超声波辅助提取,对乙醇浓度、液料比、提取温度、提取时间进行单因素实验,在此基础上以提取量为指标,利用响应面法优化工艺条件;通过对DPPH、ABTS及超氧阴离子自由基清除率的测定,评价其多酚类物质的抗氧化活性。结果表明:黑果腺肋花楸多酚最佳提取条件为液料比44∶1(m L∶g)、乙醇浓度55%、提取温度45℃、提取时间90 min,在此条件下黑果腺肋花楸多酚提取量达19.549 mg/g。黑果腺肋花楸多酚对DPPH、ABTS及超氧阴离子自由基有较强清除作用,并与其质量浓度呈正相关关系,说明其多酚具有良好的抗氧化活性。      

超声辅助复合酶法提取花椒多酚工艺及抗氧化作用研究

以花椒为研究对象,选择复合酶加入量、料液比、酶解时间和酶解温度进行单因素实验,以单因素结果为参考,利用响应面法优化超声辅助复合酶法提取花椒多酚工艺,并对其DPPH自由基及ABTS自由基体外抗氧化活性进行研究。结果表明,花椒多酚最佳提取工艺:超声功率180 W,溶液pH=5.0(磷酸盐缓冲液)时,复合酶用量1.28%,料液比1∶26(g/mL),酶解温度41℃,酶解时间31 min,此时,多酚得率为21.98%,与预测值接近,表示该提取方法可靠、可行。当花椒多酚浓度为0.8 mg/mL时,对DPPH、ABTS自由基均有较强的清除作用,且略小于VC的,说明其具有较强的抗氧化性。这为花椒药食两用资源开发、利用提供参考。     

超声辅助酶解提取水蜜桃果核多酚工艺优化及抗氧化性研究

目的:挖掘水蜜桃果核作为特色农产品加工副产物的利用途径。方法:考察酶添加量、超声温度、乙醇体积分数和超声时间对水蜜桃果核多酚提取量的影响，并分析其抗氧化性能。结果:果核多酚的最佳提取工艺为酶添加量5.2%、超声温度63℃、乙醇体积分数60%、超声时间37 min,此条件下果核多酚提取量为8.63 mg/g。多酚提取物对ABTS自由基、DPPH自由基、羟自由基、超氧阴离子自由基清除率分别为75.22%,85.91%,44.72%,45.76%,对4种自由基的半抑制质量浓度(IC₅₀)分别为0.099,0.098,0.332,0.320 mg/mL。结论:超声辅助酶解法可有效提取水蜜桃果核中的多酚，水蜜桃果核多酚具有良好的抗氧化活性。     

杏仁及杏仁皮多酚超声提取优化及抗氧化能力差异性研究

为获得杏仁及杏仁皮内多酚提取的最优方案,采用超声波处理样品,以料液比、超声温度、功率和时间为影响因素多酚得率为指标进行研究。结果表明:杏仁多酚超声提取最佳条件为料液比1∶10、超声温度50℃、超声功率400 W,超声时间60 min。而杏仁皮多酚超声提取最佳条件为料液比1∶10、超声温度60℃、超声功率400 W,超声时间60 min。采用还原力、OH、DPPH和ABTS自由基清除率四个抗氧化能力指标对杏仁及杏仁皮多酚的抗氧化能力进行差异性分析,以期为杏仁多酚这一功能性成分的开发提供参考依据。研究结果表明,杏仁多酚抗氧化能力大小与其含量成正比。甜杏仁多酚的还原力、OH和ABTS自由基清除率均高于苦杏仁多酚,而甜苦杏仁多酚的DPPH自由基清除率接近一致,且在0.024 mg/m L浓度时依次为25.4%和23.7%。甜苦杏仁皮多酚抗氧化能力差异不明显,其还原力、DPPH和ABTS自由基清除率三者基本一致,而在0.24 mg/m L浓度时,甜杏仁皮多酚的OH自由基清除率约为苦杏仁皮的2倍。总体来说,甜杏仁多酚的抗氧化能力优于苦杏仁多酚,潜在利用价值更高。      

铁皮石斛多糖复合酶法提取工艺及其抗氧化性

探讨复合酶法提取铁皮石斛多糖的最佳工艺以及酶解多糖的抗氧化活性。利用单因素及L₁₈(3⁷)正交实验研究了酶配比、酶浓度、酶解温度、酶解时间、料液比及pH对多糖得率的影响,并通过清除DPPH、ABTS自由基研究酶解多糖的抗氧化活性。结果显示酶解最优条件:中性蛋白酶与纤维素酶比例为2:1,酶浓度为10%,料液比为1:120,酶解温度为55 ℃,pH6.0,酶解时间为3 h,在此条件下多糖得率为43.85%±1.8%;酶解多糖对DPPH、ABTS自由基的IC₅₀分别为1.331、0.467 mg/mL,说明酶解石斛多糖具有较好的抗氧化活性。     

青荚叶多酚超声波辅助提取工艺及抗氧化活性研究

确定超声波辅助提取青荚叶多酚的最佳工艺条件及其体外抗氧化活性。在单因素实验的基础上,固定超声功率65 W,提取次数2次,通过响应面法优化设计提取多酚的工艺参数,并对其抗氧化活性进行测定分析。结果表明:超声辅助提取青荚叶多酚的最佳工艺参数为乙醇体积分数40.8%、提取时间4.8 min、料液比1∶60(g∶m L)、提取温度67.5℃,多酚提取量为29.43 mg/g。青荚叶多酚具有较强的还原能力,清除DPPH自由基和ABTS+·自由基IC50分别为44.28、35.07 mg/L。因此,青荚叶可作为潜在天然抗氧化剂应用于食品和医药工业中。     

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