大米抗性淀粉压热处理制备工艺的研究

抗性淀粉以其显著优点及特殊的生理功能,成为食品营养学的一个研究热点。以大米淀粉为原料,制备大米抗性淀粉对大米的深加工具有重要的经济意义。以抗性淀粉得率为评价指标,通过单因素及正交试验研究了压热法制备抗性淀粉的最佳工艺参数。结果表明,对大米淀粉进行压热处理时,影响抗性淀粉得率的主次因素为:热处理温度热处理时间淀粉乳质量分数,最佳工艺条件为:热处理温度120℃,热处理时间70 min,淀粉乳质量分数30%。采用此组合进行验证性试验得抗性淀粉产率为9.54%。     

压热法制备荞麦抗性淀粉的研究

以荞麦淀粉为原料,通过单因素及正交试验研究了压热法制备抗性淀粉的最佳工艺参数.结果表明:淀粉乳质量分数为20%,调节pH值为7.O,120℃压热处理90 min,4℃放置24 h.按此工艺参数制备荞麦抗性淀粉,其得率可达到15.54%.     

纤维素酶-压热法制备马铃薯抗性淀粉工艺参数优化

为了提高抗性淀粉的得率,并获得抗性淀粉制备方法的最佳工艺参数,该试验以马铃薯淀粉为原料,抗性淀粉得率为评价指标,采用纤维素酶-压热法制备马铃薯抗性淀粉。研究淀粉乳浓度、酶添加量、酶解时间、压热温度、压热时间5个因素对马铃薯抗性淀粉得率的影响,在单因素试验的基础上,通过正交试验优化得出马铃薯抗性淀粉的最佳制备工艺条件,即淀粉乳含量25%、淀粉乳pH 5.0、酶用量30 U/mL、酶解时间50 min、压热温度125 ℃、压热时间30 min、老化温度4 ℃、老化时间18 h,在此条件下抗性淀粉的得率为30.33%。     

反复冻融处理对大米RS3型抗性淀粉产率的影响

以大米淀粉为原料,采用反复冻融法制备了大米RS3型抗性淀粉,研究了反复冻融处理对大米RS3型抗性淀粉产率的影响,并优化了工艺参数。实验结果表明,大米RS3型抗性淀粉冻融法制备过程中,影响因素依次为:冻融温度结晶时间冻融次数淀粉乳浓度,而且冻融温度对大米RS3型抗性淀粉的产率影响最显著,其次为结晶时间和反复冻融次数,淀粉乳浓度影响最小。大米RS3型抗性淀粉最佳制备工艺参数:冻融温度为-18℃(解冻温度25℃)、反复冻融次数为15次、淀粉乳浓度为20%、结晶时间为48 h,在此条件下大米RS3型抗性淀粉产率最大可达14.97%。研究实验结果可为大米RS3型抗性淀粉加工提供依据。     

压热法制备白扁豆抗性淀粉的研究

研究压热法制备白扁豆抗性淀粉的工艺参数.以白扁豆淀粉为原料,采用压热法制备RS3型抗性淀粉,并通过单因素试验和正交试验,以抗性淀粉的产率作为评价指标确定抗性淀粉制备的最佳工艺参数.实验结果表明抗性淀粉制备的最佳工艺参数为淀粉糊浓度15%,pH为8,温度为125℃,时间为1.5 h,老化处理时间为36h,在此工艺条件下制...     

大米抗性淀粉双酶制备及其结构表征

以大米淀粉为原料,α-淀粉酶与普鲁兰酶为酶解剂,利用单因素试验研究大米抗性淀粉的制备工艺条件;通过抗酶解试验研究了其抗酶解性;采用扫描电子显微镜(SEM)、差示扫描量热仪(DSC)和X-射线衍射(X-RD)表征了大米抗性淀粉的结构。确定最佳工艺条件为:pH 5.5、温度80℃、反应时间40 min、酶α-淀粉用量4 u/g,抗性淀粉得率为45.2%。利用抗酶解试验,通过与单酶法和湿热法制备得到的抗性淀粉相比较,发现双酶法制备的抗性淀粉具有较强的抗酶解性能,24 h时的酶解率为8.02%。DSC、SEM和X-RD分析表明:双酶解法制备所得抗性淀粉具有糊化热性能稳定、空间结构紧密以及结晶度高等特点。表明双酶法制备的大米抗性淀粉抗消化能力强。     

抗性淀粉工业化生产工艺的优化研究

以普通玉米淀粉为原料,通过正交实验确定了压热法和酸解法生产抗性淀粉的最佳工艺,研究了各工艺参数对抗性淀粉产率的影响.通过成本和产率的对比,确定酸解法适合工业化生产,其最佳工艺为:淀粉乳浓度20%,1%HCl水解1h后.沸水蒸煮2h,在4℃条件下储藏24h,抗性淀粉得率为27.24%.     

压热法制备荞麦抗性淀粉工艺优化

研究了压热法制备荞麦抗性淀粉的工艺参数。比较了不同淀粉乳浓度、热处理温度、热处理时间、淀粉乳pH值对荞麦抗性淀粉得率的影响。采用三因素二次回归旋转正交组合设计,优化荞麦抗性淀粉制备参数,建立了各因子与荞麦抗性淀粉得率关系的数学回归模型,确定了最佳的制备条件:淀粉乳浓度为59.41%,压热处理温度为123.33℃,压热时间60.79min,荞麦抗性淀粉的产率理论最高值可达16.6053%。     

压热法制备燕麦抗性淀粉的工芝研究

通过单因素和正交实验,确定压热法制备燕麦抗性淀粉的最佳工艺参数为:淀粉乳浓度20%、pH6.0,经沸水预糊化后在121℃压热处理50min,冷却至室温,在4℃条件下保存24h,80℃烘干24h.按该工艺制备燕麦抗性淀粉,其得率可以达到17.26%.     

挤压-酶解联用抗性淀粉制备工艺的优化研究

为制备高含量抗性淀粉,以玉米淀粉为原料,采用双螺杆挤压机挤压预处理与普鲁兰酶酶解技术联用的方法,研究了挤压参数物料含水量、螺杆转速、机筒温度和喂料速度对抗性淀粉含量的影响。通过线性回归分析确定最优工艺条件为:物料含水率20%、螺杆转速300 r/min、机筒温度145℃、喂料速度37.5 kg/h,在此条件下抗性淀粉质量分数达(24.72±0.87)%。通过样品中直链淀粉含量、抗性淀粉含量、扫描电镜图和X-射线衍射图对比,说明挤压-酶解联用技术制备的淀粉直链淀粉含量和抗性淀粉含量增加,淀粉颗粒形成大小不匀的多孔疏松结构,淀粉晶体类型由A型转变为B+V型。     

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