天麻苦瓜面条加工工艺研究

以高筋小麦粉为原材料,添加天麻粉、苦瓜粉制备纯天然的营养面条。以感官评分为评价标准,在单因素试验的基础上,研究天麻粉、苦瓜粉、饮用水的添加量以及面团熟化时间对天麻苦瓜面条品质的影响。结果表明:影响天麻苦瓜面条工艺的顺序为面团熟化时间饮用水添加量天麻粉添加量苦瓜粉添加量。天麻苦瓜面条的最佳工艺条件:以面粉质量为基准,天麻粉添加量1.0%、苦瓜粉添加量2.5%、饮用水添加量29.0%、熟化时间35 min。在该工艺条件下,天麻面条的感官评分为88.7,熟断条率为0。     

浸泡和微波处理对三种高粱熟化的影响

为研究浸泡和微波处理对三种高粱熟化工艺参数的影响,采用单因素实验的方法,探讨浸泡时间和浸泡温度对高粱吸水率,以及微波时间和微波功率对高粱蒸煮熟化程度和熟化时间等工艺参数的影响。结果表明,随着浸泡时间的增加,三种高粱的吸水率均呈现先上升后平稳的趋势,龙米粮1号、龙杂13号和红糯高粱的最佳浸泡时间分别为2、2和3 h;随着浸泡温度的增加,三种高粱的吸水率呈上升的趋势,最佳浸泡温度分别为45、35和35 ℃。在最佳浸泡时间和浸泡温度条件下,当微波功率600 W和微波处理8 min时,龙米粮1号高粱熟化程度达到100%,蒸煮熟化时间缩短20 min;微波功率800 W和微波处理时间11 min时,龙杂13号高粱熟化程度达到100%,蒸煮熟化时间缩短20 min;微波功率800 W和微波处理时间11 min时,红糯高粱熟化程度达到100%,其蒸煮熟化时间缩短15 min。研究确定了三种高粱最佳浸泡和微波处理工艺参数,为高粱熟化工艺提供了技术参数。     

面团熟化对面条品质影响研究进展

该文概述面条生产发展过程,并介绍面条熟化工艺,对熟化概念,面团熟化作用和要求及影响熟化因素进行详细阐述。     

面条熟化工艺研究进展

阐述了面团熟化的机理以及在熟化过程颗粒中淀粉发生的变化,总结了前人对熟化工艺的研究成果,并对现在工业生产中常用的面团和面带熟化工艺做了介绍。针对原面条评价标准主观性过强及改进后缺乏统一标准体系的特点,有必要建立一个同仪器评价相结合的标准体系。     

面团熟化对面条品质影响研究进展

概述了面条生产发展过程,并介绍面条熟化工艺,对熟化概念,面团熟化作用和要求及影响熟化因素进行详细阐述。结论：由于面团形成过程中传质和化学变化进程较为缓慢,和面过程中外部供给机械能量转化成面团物质内能,所以面团从和面机移出时属于不稳定状态,必须经熟化处理,即静置或进行低速搅拌,以消除面团内应力,调整面团内部结构。     

面筋含量与面筋指数在面团熟化过程中的变化

以高筋粉、中筋粉、低筋粉为原料粉.三种原料粉在温度为30℃,湿度为70%的条件下,分别选取熟化0min,18min,36min,54min,72min,90min为熟化点来制取样品.采用手洗法测定各熟化时间点上的湿面筋含量;利用干面筋仪与面筋指数仪测定各熟化时间点上的干面筋含量及面筋指数.得到面筋含量与面筋指数在面团熟化过程中的变化规律,从而为制面行业根据产品要求,制定最佳熟化时间提供了理论上的依据.     

天麻面条加工工艺研究

以德江天麻、面粉为原材料进行实验室制作天麻面条,在单因素试验的基础上,选择加水量、天麻粉添加量、面团熟化时间、面带熟化时间为自变量,天麻面条感官评分为评价指标,设计L9(34)的正交试验,研究各自变量交互作用及其对天麻面条品质的影响。试验结果表明,天麻面条的最佳工艺条件为:加水量为37%、天麻粉添加量为3%、面团熟化时间为30 min、面带熟化时间25 min,在此工艺条件下,天麻面条感官评分为89.6。     

快速发酵冷冻面团馒头的品质变化研究

本文研究快速发酵工艺条件下冷冻面团的品质变化,以及添加剂对馒头品质的影响.观察测量馒头的比容、柔软性、弹性、组织结构等(与空白的面团相比)的方法来评价冷冻面团和馒头品质的变化,并以发酵时间、单甘脂、Vc、CMC进行了正交试验并获得了最佳配方:单甘脂0.35%,Vc 0.12%,CMC 0.075%.     

压延对面团纵横向拉伸应力特性的影响

本文对面团经压延后产生的纵横向应力的差异现象进行了研究,面团纵向抗拉应力明显大于横向抗拉应力.同时提出了影响压延后面团纵横向应力的差异的因素,初步研究了加水量、熟化时间、压延道数和静置时间对面团纵横向应力影响,为进一步研究面团流变学提供了新的依据.     

响应面法优化酸面团馒头的加工工艺

通过响应面试验设计对酸面团馒头加工工艺进行优化。通过单因素试验、Plackett-Burman试验和最陡爬坡试验筛选出发酵时间、发酵温度、加面碱量为显著影响因素以及最佳响应区域,采用Box-Behnken设计进行响应面试验,以酸面团馒头感官评分为响应值得到最佳工艺参数。各因素对酸面团馒头感官评分的影响顺序为:发酵温度发酵时间加面碱量,最佳工艺条件为:发酵时间4.25 h,发酵温度30℃,加面碱量1.0%。响应面法可以较好地对酸面团馒头加工工艺进行优化。     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

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.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.