小麦籽粒淀粉品质与蛋白质品质关系的初步研究

通过测定32个小麦品种籽粒的11个淀粉品质性状及10个蛋白质品质性状，分析了各性状之间的简单相关关系。结果表明：直链淀粉含量与清蛋白含量显著正相关，与支链淀粉含量、膨胀势、高峰粘度、衰减值、粗蛋白含量、醇溶蛋白含量、谷蛋白大聚合体含量、沉降值显著负相关；支链淀粉含量与糊化温度显著负相关，与沉降值、面筋指数显著正相关；膨胀势、高峰粘度、低谷粘度、最后粘度两两间极显著正相关；衰减值与醇溶蛋白含量、谷蛋白大聚合体含量、沉降值，糊化温度与球蛋白含量呈显著正相关；回生值与面筋含量，峰值时间与沉降值显著负相关。文章还分析了淀粉品质和蛋白质品质与蒸煮类食品品质的关系。     

玉米籽粒品质性状及其相互关系分析

通过测定55个玉米品种（系）籽粒的物理性状、淀粉品质及蛋白质组分，分析它们之间的简单相关关系。结果表明：容重与各淀粉组分含量呈负相关，与角质率、低谷粘度、最终粘度、回冷值、峰值时间、糊化温度呈极显著正相关；角质率与醇溶蛋白、谷蛋白、总蛋白含量及峰值时间和糊化温度呈极显著正相关，与膨胀势、峰值粘度和稀懈值呈显著负相关；直链淀粉含量与稀懈值负相关，与膨胀势、峰值粘度、低谷粘度、最终粘度、回冷值、峰值时间和糊化温度均表现一定的正相关；支链淀粉含量、总淀粉含量以及支／直比与糊化温度正相关，与其它粘度指标负相关；峰值粘度与低谷粘度、稀懈值、最终粘度和回冷值的相关程度较高，是衡量淀粉糊化特性的最重要指标；醇溶蛋白与总蛋白和粘度性状问的关系更密切，醇溶蛋白含量的变化对于总蛋白含量变化及淀粉特性的影响最大。文章还提出今后要加强支链淀粉、峰值时间、糊化温度和醇溶蛋白含量等对加工品质影响的研究。     

糯小麦粉与普通小麦粉配粉糊化特性的研究

选用糯小麦品种中糯一号与普通小麦(非全糯小麦)品种豫麦47、温6和澳大利亚优质面条小麦品种Gamenya,进行籽粒蛋白质含量、淀粉含量及直链淀粉含量的测定。并将中糯一号面粉分别与豫麦47、温6面粉配粉,进行了RVA试验(快速粘度分析),研究了三种单一品种面粉及其配粉的糊化特性。结果表明:中糯一号籽粒蛋白质含量、淀粉含量与供试普通小麦品种相近。但其直链淀粉含量很低,仅为1. 45%,远低于供试普通小麦品种。在RVA试验中,中糯一号面粉糊化快,峰值时间比普通小麦缩短了一半,其粘度下降到低谷后,粘度曲线变化平缓,回冷值很小,明显与供试普通小麦不同。糯小麦与普通小麦配粉的粘度曲线呈双峰状,其粘度参数因糯、普小麦配粉比例不同而不同。总之,在普通小麦粉中加入糯小麦粉后,面粉直链淀粉含量和糊化特性发生了变化,对面制食品品质将产生一定的影响。     

糯小麦“山农糯麦1号”籽粒及淀粉品质分析

为更好地了解糯小麦的品种特性,以山东省第一个审定的高产糯小麦“山农糯麦1号”为材料,研究其籽粒和淀粉特性。结果发现：该品种几乎不含直链淀粉（仅0.1%）,较普通小麦具有较高的蛋白质含量（16.4%）和面粉白度（81.2%）。扫描电镜观察淀粉粒度分布不均匀,A型淀粉颗粒较多。快速粘度分析（RVA）测定表明淀粉具有较低的糊化温度,较短的糊化时间,较低的峰值黏度、最终粘度和回生值。加工时面团吸水率明显较高,形成时间大于稳定时间。这些结果将为山农糯麦1号适于用作配粉和加工食品提供参考依据。     

糯性普通小麦的籽粒成分和淀粉品质研究

对5个组合的13个糯麦F6（或F5）株系及其亲本的籽粒成分，直链淀粉含量和膨胀势进行测定，以及分析了它们的淀粉糊化过程和糊化参数，比较它们之间的差异。结果表明：糯性小麦籽粒的蛋白质含量，湿面筋含量均高于相应的亲本，而淀粉含量则低于相应的亲本，糯性小麦株系的直链淀粉含量远远低于其亲本；糯麦淀粉的膨胀能力和吸水力大于其亲本；糯麦株系的RVA高峰粘度，低谷粘度，最后粘度，反弹值和峰值时间显著低于其亲本。糯麦株系面粉间的RVA粘度参数值大同小异，讨论了糯性小麦的应用前景。     

小麦面粉对油炸型方便面感官品质的影响

以同一厂家不同产品不同批次的方便面生产专用面粉和相应的成品为研究对象,测定面粉的总淀粉含量、直链淀粉含量、降落值以及面粉的糊化特性、方便面的TPA 实验指标和感官品质等指标,并对其相关性进行分析,探讨面粉各指标对方便面感官品质的影响。结果表明：降落值和直链淀粉与起始糊化温度呈极显著正相关,与峰值黏度和方便面的各个感官指标呈极显著负相关;总淀粉含量与各个感官指标成极显著正相关。因此面粉中直链淀粉含量和降落值较低、总淀粉含量较高的时候,方便面成品感官品质较好。     

小麦蛋白质和面条品质的关系

正面条是我国传统的面食品之一,目前手工制作面条的工艺已趋落后,绝大多数为大规模商业化生产。面条品质与加工该面条的面粉中的蛋白质等质量和数量关系密切。1蛋白质与面条品质面粉中的许多成分与面条的食用品质都有着不可分割的联系,其中尤以蛋白质和淀粉的影响最大。小麦面粉中蛋白质含量的变异范围较大,一般在9%～17%之间。虽然蛋白质的含量比淀粉低得多,但它对面条品质却有非常重要的作用。蛋白质吸水形成的面筋赋予小麦面团独特的物理特性,并使小麦食品成为最受人们欢迎的佳肴。一般而言,蛋白质含量与面条的白度等外观品质呈显著负相关。蛋白质含量过高,面筋强度过强,不适于机器加工(回缩严重),面条表面粗糙,白度下降,干燥后面条容易弯曲,     

小麦籽粒淀粉理化特性与面条品质关系研究

研究中国小麦的淀粉理化特性及其与面条品质的关系．为优质面条小麦品种的选育提供依据。测定了全国11个省市育成品种和高代品系的294份面粉样品和29份引进品种面粉的淀粉理化特性和面条品质,对其相关性进行了统计分析。结果是中国小麦品种直链淀粉含量的遗传资源相对丰富,面粉膨胀势偏低,淀粉糊化特性与国外品种相近,面条品质表现较好（平均评分85．27分）。直链淀粉含量、膨胀势和糊化峰值粘度与面条品质高度相关,     

小麦胚乳中直链淀粉含量分布及其对面条品质的影响

在同一生产线上对同一品种小麦按加工系统取制面粉样品,测定各粉样的直链淀粉含量;选择部分样品在其中添加整个粉路中最具代表性的系统面粉制成的谷朊粉,使各样品蛋白质含量相等、质量接近,在这种的前提下,研究直链淀粉含量对面条品质的影响。研究结果表明,小麦胚乳中,越接近皮层的部位,直链淀粉含量越低;越接近麦心的部位直链淀粉含量越高。小麦胚乳中的淀粉总量与面条品质无明显的相关性,而直链淀粉及支链淀粉含量对面条品质影响较大。直链淀粉含量与面条感官评价的表观状态、适口性、韧性、黏性、光滑性、食味及总评分都呈极显著负相关;与面条的煮制特性的干物质吸水率、蛋白质损失率和干物质损失率呈极显著正相关;而与面条质构仪TPA测定参数的黏合性、硬度和咀嚼性呈极显著负相关。     

不同制粉工艺对面粉粉质特性和糊化特性的影响

脱皮制粉工艺先除去小麦部分皮层,再入磨,使后序的皮磨以及清粉系统大大简化.本试验利用两种工艺加工面粉后,用RVA测定和分析了面粉粉质特性和糊化特性的变化.结果表明,脱皮工艺下面粉的损伤淀粉含量减少、淀粉平均粒度变大、α-淀粉酶含量减少;降落数值和平均粒度分布分别与低谷粘度呈显著正相关（r=0.581,p＜0.05;r=0.603,p＜0.05）,衰减度和平均粒度呈显著的负相关（r=0.605,p＜0.05）;制粉工艺对中筋的南阳白麦和高筋的8901二等粉的影响最为显著,脱皮工艺下这两种面粉的峰值粘度和最终粘度明显增加,并且其衰减度较大;脱皮工艺的低谷粘度均高于传统工艺的同等面粉,但回生值较低.     

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.