桂淮系列淮山淀粉性质的测定

选用广西新培育的淮山品种提取淀粉,研究桂淮系列淮山淀粉性质。结果表明：桂淮7号淮山淀粉具有峰值黏度、糊化温度以及回生值低的特点;桂淮8号峰值黏度高,峰值时间短,热稳定性差;紫淮山的冻融稳定性最差;桂淮系列淮山淀粉的凝聚力均较高;静置2?h后桂淮系列淮山淀粉的凝沉性较差;60～90?℃水浴条件下桂淮系列淮山淀粉的溶解度较好。不同品种淮山淀粉的各性质存在差异,可用于指导不同品种淮山的深加工应用,同时为进一步选育适合加工型的淮山新品种提供参考。     

不同品种淮山全粉的理化性质比较分析

为了探索淮山新的应用途径,本文以桂淮系列6个品种为原料,通过热风干燥制备淮山全粉,并研究了其理化性质。结果表明:6个品种淮山全粉的理化性质存在显著差异,6个品种全粉中淀粉、总糖和蛋白质含量分别为60.36~62.63%、72.32~78.77%和12.0~13.0%,灰分为3.05~3.25%,脂肪含量约为0.5%,尿囊素、儿茶素、丁香酸和黄酮含量分别为26.48~69.08 mg/g、0.25~1.64 mg/g、0.32~0.58 mg/g和0.31~0.94 mg/g。淮山全粉的平衡含水量低,吸附等温线属于BET分类中的Ⅱ型吸附等温线。桂淮6号、桂淮2号和桂淮3号淮山全粉平衡含水量高于其他品种。桂淮5号色泽最佳,碘蓝值和白度最高,且丁香酸和黄酮含量最高。桂淮4号的持水力最佳,儿茶素含量最高。桂淮6号最短的分散时间,尿囊素含量最高,桂淮2号稳定时间最长,但分散时间最长。桂淮1号冻融稳定性最好,适合于用于冷冻食品加工。     

不同品种马铃薯淀粉的微观结构及物化性质比较分析

以黑龙江、甘肃、北京三地的11个马铃薯品种为研究对象,比较分析不同品种马铃薯淀粉的直链淀粉含量,淀粉颗粒大小、热特性、微观结构特征、黏度特性、流变学特性的差异,分析不同品种马铃薯淀粉微观结构特征与物化特性的相关关系。结果显示,布尔斑克的直链淀粉含量最高为16.64%,不同品种淀粉D50值的变化范围是59.40~323.90 μm,荷兰薯的起始糊化温度、峰值温度、糊化焓值最高,淀粉颗粒多为圆形或椭圆形,陇薯9号的糊化温度最低,为62.27 ℃,陇14和陇薯7号的贮能模量显著高于其他品种。D50值与淀粉的糊化焓值（r=0.596 3）、糊化温度（r=0.502 4）呈显著的正相关,与直链淀粉含量（r=-0.576 5）、回生值（r=-0.551 8）呈显著的负相关;淀粉热特性的起始糊化温度与黏度特性的峰值温度（r=0.961 0）、峰值时间（r=0.733 6）、糊化温度（r=0.933 9）呈极显著的正相关。不同品种马铃薯淀粉的微观结构和物化性质间存在显著的相关关系,为马铃薯淀粉的加工利用及育种提供依据。     

青藏区主要青稞品种淀粉理化特性分析

以青藏区主要青稞品种藏青25、冬青8号、藏青148、喜拉19、昆仑12号、藏青320、北青6号为材料,采用湿法提取淀粉,对青稞淀粉理化特性进行分析。结果表明,7种青稞淀粉颗粒多为圆饼状,表面光滑;其偏光十字形状及明显程度差异不大,十字交叉点都接近于淀粉颗粒的中心位置,呈"X"形;平均粒径为18.30μm~20.17μm,其中藏青148的淀粉颗粒粒径最小,冬青8号的最大;直链淀粉含量由高到低依次为:冬青8号昆仑12号藏青320藏青148喜拉19北青6号藏青25,具有显著性差异;淀粉糊的透明度和热糊稳定性均较好。     

不同品种鲜食型甘薯烘烤后品质的研究

为探究不同甘薯品种烘烤后的品质,以8个不同品种的甘薯为材料,测定其品种特征特性及烤制后的相关理化、感官、质构特性等指标,并对各指标进行相关性分析和主成分分析。结果表明,冀薯8号的干率最高,蛋白质含量最低;济薯26干率、总糖含量和淀粉含量均最低;冀薯7号总糖含量和淀粉含量最高;冀粉2号蛋白质含量最高;冀紫薯3号纤维素含量最高;冀元1号的纤维素含量最低。基于质构指标及主成分分析建立2个模型,得出8种甘薯质构综合得分由高到低依次为冀紫薯3号、冀粉3号、冀粉2号、烟薯25、济薯26、冀薯7号、冀元1号、冀薯8号。感官评价得出冀粉2号接受度最好,冀薯8号接受度最差。相关性分析表明营养品质、质地品质及感官品质之间具有一定的相关性。综合分析得出冀粉2号为8个甘薯品种中最优品种,其次是烟薯25、冀紫薯3号、济薯26、冀粉3号、冀薯7号、冀元1号、冀薯8号。     

甘肃定西地区主栽品种马铃薯颗粒全粉品质分析

以甘肃定西地区主栽的7个品种马铃薯为原料,采用微波工艺生产马铃薯颗粒全粉,并测定其原料品质指标(干物质、总淀粉、直链淀粉、还原糖、维生素C含量)和其颗粒全粉的功能指标(蓝值、持水性和持油性)。结果表明:除克新1号品种马铃薯的干物质含量偏低、还原糖含量较高以外,其余6个品种费乌瑞它、陇3、青薯6号、冀张薯8号、陇薯6号、庄薯3号均符合加工全粉的要求;马铃薯原料中总淀粉含量高,则游离淀粉的含量相对较高。7个品种马铃薯颗粒全粉的蓝值顺序为费乌瑞它冀张薯8号庄薯3号青薯6号陇薯3号陇薯6号克新1号;持水性顺序为冀张薯8号费乌瑞它青薯6号庄薯3号陇薯3陇薯6克新1号;持油性高低顺序是克新1号青薯6号冀张薯8号庄薯3号陇薯3号陇薯6号费乌瑞它。该结果可为甘肃省定西地区马铃薯颗粒全粉生产的原料选择和颗粒全粉应用提供科学依据。     

不同品种马铃薯全粉品质特性分析

选取河北省张家口地区7个马铃薯品种,通过色泽、微观形态、基本成分、功能特性、糊化特性及体外消化特性等指标的测定,研究了不同品种马铃薯全粉的品质特性.结果表明,冀张薯8、22号和京张薯2号干物质含量均高于22.50％,高于大西洋、夏波蒂两个国外品种;冀张薯8、12号淀粉含量高于大西洋(70.87％);京张薯2号还原糖含量...     

再生季稻米蒸煮食味品质与糊化特性、淀粉晶体结构研究

以衡阳实验点种植的8个不同品种再生季稻米为研究材料,对其蒸煮食味品质、糊化特性及淀粉的晶体结构进行了测定和相关性分析。结果表明：供试品种中和两优1号和晶两优1468的再生季稻米直链淀粉含量适中,胶稠度长,糊化温度低,其中和两优1号的结晶度低,晶两优1468淀粉内部有序程度高,RVA谱特征值表明这两个品种均具有较好的蒸煮食味品质。相关性分析发现不同品种再生季稻米的直链淀粉含量与相对结晶度显著负相关,同时,相对结晶度与碱消值呈显著负相关,与胶稠度呈显著正相关;1047/1022 cm-1值与峰值时间、最低黏度呈显著负相关。表明再生季稻米中直链淀粉含量变化会影响淀粉的晶体结构,改变其糊化特性,导致稻米蒸煮食味品质的差异。     

糜子淀粉理化性质的分析

为掌握陕西省主要糜子品种的淀粉理化性质,以陕北地区3个主要糜子品种为材料,研究了糜子淀粉的颗粒结构、糊化特性、糊特性以及凝胶质构特性.结果表明:糜子淀粉颗粒为多角形或球形,粒径为1.9～10.0μm,偏光十字较为明显,微晶结构为A型;3个糜子品种的直链淀粉含量为2.85%～19.30%,碘蓝值较高;糜子淀粉的热糊稳定性、冷糊稳定性优于马铃薯淀粉,酸、碱对糜子淀粉糊黏度性质的影响较大,在碱性(pH 10.0)条件下,糜子淀粉起始糊化温度的升高幅度大,冷糊稳定性更强.糜子淀粉糊的透明度较低,冻融稳定性和凝胶形成能力较差,凝沉顺序依次为榆糜1号淀粉>榆糜2号淀粉和玉米淀粉>YM0506淀粉和马铃薯淀粉.榆糜2号淀粉凝胶的硬度较高,回弹性和黏聚性均低于玉米淀粉和马铃薯淀粉.     

3种栗属坚果淀粉的结构及其理化特性

以我国南北方种植的3种栗属坚果(板栗、锥栗和日本栗)为原料提取淀粉,通过扫描电镜(SEM)、X射线衍射仪(XRD)、差示扫描量热仪(DSC)、快速黏度仪(RVA)等仪器和方法,研究14个品种淀粉的颗粒结构和理化特性的差异,并对其进行相关性分析。结果表明:栗属坚果的直链淀粉含量差异显著,淀粉颗粒形态较为复杂,颗粒表面光滑完整;淀粉均属于C型晶体,结晶度为20.43%～25.63%,淀粉的冻融稳定性好。不同品种淀粉的颗粒结构和理化特性之间存在多种相关性,说明直链淀粉含量和结晶结构影响淀粉的理化性质。     

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.     

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.     

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.