面包老化抑制因素的研究

在西方国家,面包是餐桌上的主食,面包的质量与人们的健康和幸福息息相关.随着经济水平的提高,面包已经悄悄走进了我们的生活.但是,老化的面包口感差,易掉屑且香味丧失,不为广大消费者所接受.我们需要研究面包老化的机理,并从理论上寻找抑制面包老化的方法,提高面包的质量.本文综述了近年来国内外对面包老化的研究结果,从水分、淀粉结晶、添加剂、淀粉酶、贮存和温度几方面论述了抑制面包老化的方法.并对抑制面包老化,全面提高面包质量的研究趋势进行了展望.     

面包老化抑制因素研究

随着经济水平提高,面包已悄悄走进我们的生活;但是,老化面包口感差,易掉屑且香味丧失,不为广大消费者所接受。为此,需要究面包老化机理,并从理论上寻找抑制面包老化方法,提高面包质量。该文综述近年来国内外对面包老化研究成果,从水分、淀粉结晶、添加剂、淀粉酶、贮存和温度几方面论述抑制面包老化方法;并对抑制面包老化,全面提高面包质量研究趋势进行展望。     

影响面包老化因素及抗老化途径

该文综述近年来国内外有关面包老化研究成果,介绍影响面包老化主要因素,并从改变原辅料、添加酶制剂、乳化剂和亲水性胶体等方面论述抑制面包老化方法。     

影响面包老化因素研究进展

该文综述近年来国内外对面包老化研究成果,从水分、淀粉酶、添加剂、起酥油、贮存和温度等方面论述抑制面包老化方法,以期能对面包行业具有一定理论指导作用。     

面包老化机理及延缓老化方法的研究进展

面包老化一直以来是一个难以解决的难题,给生产和消费带来极大的损失,因此,研究面包老化机理有着重要的意义.综述了国内外近年来研究成果,从面包老化的内因和外因两方面详细论述了面包老化的机理.并提出了延缓面包老化的方法.     

γ-聚谷氨酸对夹心面包货架期的影响

人们在研究面包老化时,对水分的的迁移和分布做了大量的研究,发现面包水分的变化是老化的一个关键因素,面包中水分的损失加速了面包的老化进程。γ-聚谷氨酸可以结合面包中的水分,减缓面包在储藏状态中水分的流失,因此在同等储藏条件下可以延长面包的储藏期。利用NMR测定技术,结合电镜技术、酸价检测及感官评定分析在储藏期中面包品质的变化,分析面包中的水分变化,综合弛豫特性分析、质构特性分析、酸价测定、环境扫描电镜分析和感官评价可知,未添加γ-聚谷氨酸的夹心面包、仅果酱中添加γ-聚谷氨酸的夹心面包、仅面包中添加γ-聚谷氨酸的夹心面包和两组分均添加γ-聚谷氨酸的夹心面包的最佳品质保持时间分别为3、5、6、7d。说明γ-聚谷氨酸的添加,可以提高面包在储藏期中的品质质量,抑制面包的老化,延长面包的储藏期。     

发酵方法对面包老化的影响

研究了常见发酵方法对面包老化的影响。实验结果表明,发酵方法对面包老化的影响大小按照老化速率从高到低的顺序依次是:快速发酵法、一次发酵法、二次发酵法、过夜种子面团法、三次发酵法。其中,三次发酵法和过夜种子面团发酵法所制作的面包老化速率比较接近。随着发酵次数的增多、发酵时间的延长,所制作出的面包抗老化效果更好,面包品质更好。     

硬脂酰乳酸盐和面包

研究面包老化的原因及其防止方法,国外已有一百余年历史,并已取得较好的结果。国内近几年来由于面包的需求量增加,生产规模不断扩大,尤其是在实现四化的新的长征途中,为了改变我国人民的食品结构和减少做饭时间,出现了主食面包,这样,对于解决面包老化的问题就显得更为迫切。关于延缓面包老化的问题,国内外已有不少报导,概括这些研究的结果,可以从原材料和配方的选用,加工工艺的合理选择,添加剂的使用,面包成品的包装和贮藏条件等方面采取措施,以达到延缓面包老化的目的。近几年来,焙烤工作者都致力于使用添加剂来延缓面包老化,收效较为显著。本文就硬脂酰乳酸盐的性状,制备过程及其对延缓面包老化的效果加以讨论。     

谷氨酰胺转氨酶对藜麦-小麦面团及面包品质的影响

为开发烘焙品质较好的藜麦-小麦粉面包,利用谷氨酰胺转氨酶对其进行改良。从藜麦-小麦粉的粉质参数、糊化特性、面团质构、面包烘焙品质及老化特性等方面研究谷氨酰胺转氨酶(transglutaminase,TGase)对藜麦-小麦粉品质的影响,综合评价TGase对藜麦-小麦粉面团、面包品质的影响。结果表明,TGase增大混粉体系的吸水率、延长稳定时间。增大混合粉体系的糊化黏度、抑制体系的老化及回生。随着TGase的添加量的增大,面团硬度、弹性、黏聚性增大,当超过1.0%时,变化不显著(p>0.05)。面包品质结果表明,TGase的加入改善面包的持气能力,增大比容、感官评分、弹性及黏聚性,降低了面包的硬度,但是高剂量的TGase(>1.0%)会导致交联过度,面包品质降低。老化特性结果表明,TGase的加入使得面包老化程度降低,抑制面包老化。     

β-环糊精抑制面包老化及其机制初步分析

对β-环糊精(β-CD)抑制面包老化特性进行了研究。结果表明:添加2.0%的β-CD能明显地改善面包物性,延缓面包老化;一定程度上改变面包老化过程中晶体成核模式以及延缓面包储藏过程中淀粉晶型由V型向更稳定的B型晶体转化。这主要是因为在面包烘焙冷却过程中,β-CD与淀粉作用形成复合物。该复合物增强面包的网络结构,改善淀粉老化结晶环境,从而延长面包的有效储藏期。     

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