响应面法优化玉米抗性淀粉制备工艺

研究普鲁兰酶法制备玉米抗性淀粉的工艺。在单因素试验基础上,采用响应曲面法研究pH值、反应温度、反应时间和加酶量对抗性淀粉得率的影响,优化玉米抗性淀粉制备工艺,建立各因素与抗性淀粉得率关系的数学回归模型。确定最佳的制备工艺条件为普鲁兰酶加酶量12.8ASPU/g、反应时间32h、反应温度46.2℃、pH5.0。在该制备条件下,抗性淀粉得率为46.2%。     

响应面法优化微波辅助酶解制备抗性淀粉工艺研究

采用微波辅助酶解制备玉米抗性淀粉,以玉米抗性淀粉收率为指标,在单因素试验基础上,进行BoxBehnken试验设计,对耐高温α-淀粉酶添加量和酶解时间、普鲁兰酶添加量和酶解时间4个因素进行响应面优化试验分析。结果表明4个因素的影响主次关系为普鲁兰酶酶解时间耐高温α-淀粉酶酶解时间耐高温α-淀粉酶添加量普鲁兰酶添加量。响应面优化试验确定微波辅助酶解制备玉米抗性淀粉的最优工艺参数:耐高温α-淀粉酶添加量3 U/g干淀粉、酶解时间30 min,普鲁兰酶添加量8 U/g干淀粉、酶解时间4.5 h。     

超声波-酶法制备小麦RS3型抗性淀粉工艺参数的优化

以小麦淀粉为原料,抗性淀粉得率为指标,采用超声波-酶法制备小麦RS3型抗性淀粉,在优化的超声波作用条件(淀粉乳浓度15%,超声波功率225W,超声温度50℃,超声作用时间50min)基础上,通过单因素及正交试验确定最佳的酶解工艺:耐高温α-淀粉酶添加量1U/g干淀粉,耐高温α-淀粉酶作用时间20 min,普鲁兰酶添加量10 U/g干淀粉,普鲁兰酶酶解温度50℃,酶解时间7 h。经反复验证,超声波-酶法制备小麦RS3型抗性淀粉得率为13.155%。     

油莎豆复合酶法抗性淀粉的制备及纯化工艺

以油莎豆淀粉为原料,通过高温α-淀粉酶水解,普鲁兰酶脱支,对淀粉进行连续处理,研究复合酶法油莎豆抗性淀粉的制备及纯化工艺条件,单因素及正交实验结果表明,油莎豆淀粉双酶法制备抗性淀粉酶解的最佳工艺条件是:高温α-淀粉酶添加量2μ/g、酶解温度95℃、酶解时间15 min。普鲁兰酶添加量15μ/g、酶解温度50℃、酶解时间20 h。此条件下制备的油莎豆抗性淀粉得率为39.48%,抗性淀粉含量为57.72%。     

超声辅助双酶法制备RS_3型籼米抗性淀粉工艺参数优化

以微波预糊化籼米淀粉为原料,采用超声波间歇式辅助,异淀粉酶和普鲁兰酶分步脱支酶解制备了RS_3型籼米抗性淀粉。以RS_3产率为考察指标,在单因素实验的基础上,利用响应面法对制备RS_3型籼米抗性淀粉的工艺参数进行了优化。结果表明,在淀粉乳质量分数10%、异淀粉酶酶解温度50℃、异淀粉酶酶解pH5.0、普鲁兰酶酶解温度60℃、普鲁兰酶酶解pH4.5、超声功率70 W条件下,最佳工艺条件为:异淀粉酶添加量16 U/g,异淀粉酶酶解时间3 h,普鲁兰酶添加量8 U/g,普鲁兰酶酶解时间2.2 h,超声时间7 min,超声间歇时间2.3 h。在最佳条件下,RS_3型籼米抗性淀粉产率可达18.19%。     

响应面法优化板栗抗性淀粉制备工艺

为了提高板栗抗性淀粉含量,并获得抗性淀粉制备方法的最适工艺参数,本研究优化了压热—普鲁兰酶法制备板栗抗性淀粉的工艺,在单因素试验基础上,采用响应面法研究淀粉悬浮液质量分数、普鲁兰酶添加量、酶解时间和冷凝时间对抗性淀粉得率的影响,建立各因素与抗性淀粉得率关系的数学回归模型。最终根据实际工艺操作确定最佳的制备工艺条件为淀粉悬浮液质量分数11.00%,酶添加量9 PUN/g、酶解时间10 h、冷凝时间15 h。在该制备条件下,测得抗性淀粉得率为64.90%,基本符合理论预测值(65.70%)。试验证明,响应面法能够提高板栗抗性淀粉的制备率。     

微波-酶法制备RS3型玉米抗性淀粉工艺参数优化研究

运用响应面法,对微波-酶法制备RS3型玉米抗性淀粉的工艺参数进行优化。α-淀粉酶酶解的优化工艺参数为:液料比4:1,酶解温度85℃,酶解时间10min,酶浓度1．68U/g淀粉:微波糊化的优化工艺参数为:功率1．26kW,加热温度92℃,加热时间1min:普鲁兰酶脱支优化工艺参数为:酶浓度4．13 NPUN/g淀粉,酶解温度53．31℃,酶解时间3．26h。按以上工艺参数制备的抗性淀粉得率为13．45%。     

酶解处理对大米RS_3型抗性淀粉产率的影响

以大米淀粉为原料,研究比较了α-淀粉酶、葡萄糖淀粉酶和普鲁兰酶对大米RS3型抗性淀粉产率的影响,试验结果表明:普鲁兰酶对大米RS3型抗性淀粉产率影响最为显著,抗性淀粉产率相对较高。在酶法制备大米RS3型抗性淀粉过程中,α-淀粉酶在最佳添加量为1%、酶解30 min、淀粉浓度均为10%条件下,抗性淀粉产率可达14%;葡萄糖淀粉酶在酶添加量为0.5%、酶解20 min、淀粉浓度均为10%条件下,抗性淀粉产率可达15%左右;普鲁兰酶添加量为40μL/g淀粉、酶解12 h、淀粉浓度为20%条件下,大米RS3型抗性淀粉产率高可达20.57%。研究结果可为酶法制备大米RS3型抗性淀粉提供参考。     

微波-酶法制备马铃薯抗性淀粉工艺参数的优化

以马铃薯精制淀粉为原料,抗性淀粉得率为评价指标,通过单因素及正交试验确定了微波-酶解法制备马铃薯抗性淀粉的最佳工艺条件:在淀粉乳质量分数15%,微波作用时间90 s,微波作用功率800 W,耐高温α-淀粉酶添加量10 CU/g干淀粉,耐高温α-淀粉酶作用时间30 min,普鲁兰酶添加量0.10 PUN(G)/g干淀粉,普鲁兰酶酶解时间6 h,普鲁兰酶作用温度55℃的条件下,4℃老化24 h。经重复验证,RS得率最高达14.0%。     

α-淀粉酶水解马铃薯淀粉制备抗性淀粉

以马铃薯淀粉为原料,研究制备RS3型抗性淀粉制备工艺,以抗性淀粉制备产率为考察指标,探讨淀粉浓度、淀粉糊化温度、酶加量、作用时间、作用温度、老化温度和时间等对抗性淀粉产率影响。结果表明,马铃薯回生抗性淀粉最佳制备工艺参数分别为:淀粉乳浓度为10%、高压温度120℃、高压时间30min、α–淀粉酶加入量为120U/mL,淀粉溶液酶解时间30min、pH为6、老化温度4℃、老化时间12h,马铃薯回生抗性淀粉产率达1.126%。     

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