嗜冷普鲁兰酶制备玉米抗性淀粉工艺优化及其表征

以玉米淀粉为原料,采用嗜冷普鲁兰酶脱支处理和压热处理相结合的方式制备玉米抗性淀粉,考察了玉米淀粉乳质量分数、耐高温α-淀粉酶添加量、嗜冷普鲁兰酶添加量、嗜冷普鲁兰酶作用时间对抗性淀粉得率的影响,采用正交试验对压热-酶解法制备玉米抗性淀粉的工艺参数进行了优化。采用扫描电子显微镜、X-射线衍射和差示扫描量热仪对玉米抗性淀粉形貌、晶体结构、热特性进行了观察与分析。结果表明,制备玉米抗性淀粉的最佳工艺条件为：玉米淀粉乳质量分数18%、耐高温α-淀粉酶添加量7 U/g、嗜冷普鲁兰酶添加量10 U/g、嗜冷普鲁兰酶作用时间9 h。在最佳条件下,玉米抗性淀粉得率为16.84%。玉米淀粉经复合酶法处理后,抗性淀粉形成了致密的层状晶体结构,表面形态结构呈现出不同于玉米原淀粉A型晶体结构的V型晶体结构;玉米抗性淀粉的起始温度、峰值温度、终止温度和相变焓值分别为117.07、140.69、153.03 ℃和1 858.12 J/g,均高于玉米原淀粉。     

压热-酶解法制备青芒果抗性淀粉

本研究采用压热-酶解法制备青芒果抗性淀粉,实验以青芒果淀粉为原料,在压热条件和α-淀粉酶作用的基础上,研究普鲁兰酶酶浓度、酶解温度、酶处理p H和酶解时间对青芒果抗性淀粉含量的影响。正交实验结果表明,压热-酶解法制备青芒果抗性淀粉的最佳条件为鲁兰酶添加量30 U/g、酶解p H5、酶解时间15 h、酶解温度60℃,该条件下,青芒果抗性淀粉产率最高可达7.368%。     

压热-酶法制备碎米抗性淀粉的工艺及其结构特性研究

研究以碎米为原料压热-酶法制备抗性淀粉的工艺.通过单因素和正交试验,获取最佳工艺条件:淀粉浆质量浓度20%、压热温度125℃、压热时间40 min、普鲁兰酶添加量3.5 U/g干淀粉,酶解时间6 h.在此条件下碎米抗性淀粉得率为16.8%;采用扫描电镜观察分析表明碎米抗性淀粉具有更稳定的晶体结构,具有抗酶解性;运用X-...     

酶法制备抗性淀粉新工艺的研究

以普通玉米淀粉为原料,采用121℃20min压热--℃24h冷却的循环处理和酶解处理相结合的方法制备抗性淀粉,对压热-冷却循环次数和普鲁兰酶的添加顺序及酶作用时间进行研究.结果表明,在选定的酶用量(30U·mL-1)和酶作用温度(60℃)条件下,压热一冷却循环结合酶水解法,即糊化或老化1次后添加普鲁兰酶,可以显著提高普通玉米淀粉制备抗性淀粉的得率.并且老化1次后加入普鲁兰酶的作用效果更好.     

酶解-压热法制备淮山药抗性淀粉

以淮山药淀粉为原料,通过正交试验研究酶解-压热法制备抗性淀粉的最佳工艺参教.在压热法的最佳工艺基础上,通过使用普鲁蓝酶处理淀粉,使产率大大提高,该法所得的产率最高可达16.47%左右.确定压热处理最佳工艺条件为淀粉乳浓度25%,pH值8.0,121℃压热处理40 min,冷藏老化时间为36 h.确定制备抗性淀粉的最佳酶作用参数为加酶量4 U/g干淀粉,作用温度55℃,作用时间8 h.     

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。     

鲜淮山抗性淀粉的研究

为了提高鲜淮山抗性淀粉的含量,该研究以鲜淮山为原料,采用压热-双酶解法制备抗性淀粉,通过单因素试验确定鲜淮山抗性淀粉的最佳制备条件为:25%淀粉乳在105℃压热50min,添加耐热α-淀粉酶0.288 KNU/g,作用15 min,添加普鲁兰酶3U/g,作用4h,老化时间24h。该条件下抗性淀粉的质量分数为43%。     

压热-酶法提高小麦中抗性淀粉及其在蛋糕中应用研究

使用压热和酶联合制备抗性淀粉,通过单因素试验和正交试验对制备工艺进行了优化,当面粉乳浓度25%、压热温度110℃、α–淀粉酶添加量0.24%、普鲁兰酶添加量6%时,制得的小麦粉抗性淀粉含量最高。对抗性淀粉添加量对蛋糕硬度的影响进行了研究,得出抗性淀粉添加量为2%~3%时,制作的蛋糕在贮藏过程中硬度增加明显变小,起到了很好的保鲜效果。     

酶法联合压热-冷却循环处理制备抗性淀粉

本研究以玉米淀粉为原料,通过酶法联合压热-冷却循环处理制备抗性淀粉,测定酶解过程中淀粉的水解度(DE值)、脱支度和直链淀粉含量、样品抗性淀粉含量及其热稳定性,采用差示扫描量热仪(DSC)、扫描电子显微镜(SEM)分别测定抗性淀粉的热力学特性和颗粒形貌。结果表明,耐高温α-淀粉酶酶解能显著提高淀粉的水解度,耐高温α-淀粉酶联合压热-冷却循环制备的抗性淀粉含量为10.51%~12.16%;淀粉脱支度、抗性淀粉含量、直链淀粉含量随着普鲁兰酶酶解前压热-冷却循环处理次数增加而显著下降,抗性淀粉的热稳定性却得到提高;先普鲁兰酶酶解后压热-冷却循环处理3次得到的抗性淀粉含量最高,达到17.94%;抗性淀粉的糊化峰值温度为119.5℃~121.1℃,糊化焓随抗性淀粉含量的增大而增大,颗粒形状为不规则的碎石型。     

甜荞抗性淀粉制备工艺的优化及形貌特征分析

以甜荞淀粉为原料,采用响应面法优化酸法制备抗性淀粉的工艺条件,在单因素试验的基础上,选取液料比、稀酸添加量、酸解时间、4℃冷藏时间为影响因素,以抗性淀粉得率为响应值,进行响应面分析。试验结果表明,酸法制备甜荞抗性淀粉的最佳工艺条件是:液料比7.69 mL/g,稀酸添加量3.08%,酸解时间2.35 h,4℃冷藏时间37.99 h。在此条件下,抗性淀粉得率可达到36.95%。对原淀粉和抗性淀粉的颗粒形貌进行观察,淀粉颗粒结构发生很大的变化,由规则光滑的球形变为不规则的晶体结构。     

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