淀粉的消化性能与RVA曲线特征值的相关性研究

采用RVA 测定了禾谷类淀粉、块根类淀粉及豆类淀粉的黏滞性谱,并探讨淀粉的消化性能与RVA 谱特征值的相关性。结果表明,不同品种淀粉总体崩解值与易消化淀粉(RDS)呈极显著正相关(r=0.741,p ＜ 0.01),与慢消化淀粉(SDS)呈极显著负相关(r= － 0.833,p ＜ 0.01)。对于禾谷类淀粉,淀粉热糊的崩解值与RDS 呈极显著正相关(r=0.970,p ＜ 0.01),与SDS、抗性淀粉(RS)均呈显著负相关(r= － 0.906,p ＜ 0.05;r= － 0.978,p ＜ 0.01);对于块根类淀粉,崩解值与SDS 呈显著负相关(r= － 0.987,p ＜ 0.05),与RS 呈显著正相关(r=0.989,p ＜ 0.05);对于豆类淀粉,崩解值与SDS 呈负相关(r= － 1.000,p ＜ 0.05),糊化温度与RDS 呈正相关(r=0.998,p ＜ 0.05)。     

油莎豆抗性淀粉结构特征及体外消化特性研究

以油莎豆淀粉为原料，用压热法、酶法和压热-酶法制备油莎豆抗性淀粉（分别记为A-CRS、E-CRS和AD-CRS），研究其结构特征和体外消化特性。结果表明，油莎豆淀粉颗粒光滑饱满，形状不一，而抗性淀粉的形态发生显著变化，结构不完整，外观粗糙。油莎豆淀粉为A型晶体结构，三种抗性淀粉为C+V型结构。与原淀粉相比，三种抗性淀粉的平均粒径增大，RS含量、结晶度和热稳定性均显著提高，而平均聚合度降低， 其中AD-CRS的结构最紧密，结晶度最高。体外模拟消化显示A-CRS、E-CRS和AD-CRS的消化速率均小于原淀粉，其血糖指数（GI）分别为39.86、39.84、39.83，属于低GI食品(GI＜55)。综上所述，油莎豆抗性淀粉的结构较紧密，具有较强的体外抗消化能力和调控血糖的潜力。     

高压均质改性淮山药淀粉及其消化性的研究

本文研究了高压均质压力对淮山药淀粉颗粒形貌、偏光十字、粒径、结晶特性和体外模拟消化性的影响。研究结果表明:经高压均质处理后,淮山药淀粉颗粒表面破损明显,偏光十字强度减弱;淀粉粒径随均质压力的升高呈现先减小后增大的趋势,最小粒径为25.16μm(压力为40 MPa时),最大粒径为27.81μm(压力为100 MPa时);淀粉颗粒的结晶类型保持不变、仍为C型,淀粉结晶度从26.45%下降到21.00%;红外吸收光谱中3233.42、1164.01、1081.90、1050.27和1015.81 cm-1处的吸收峰变窄、强度变低,淀粉的有序程度降低。原淀粉中快速消化淀粉(RDS)、慢消化淀粉(SDS)和抗性淀粉(RS)含量分别为11.32%、7.00%和81.68%,经过100 MPa均质处理之后,RDS和SDS含量分别增加至20.63%和10.41%,RS含量则减少到68.96%。这说明高压均质处理能降低淀粉内部的结晶度,使得抗酶解能力降低,淀粉消化性提高,且压力越高,这种趋势越明显。     

颗粒态抗性淀粉结晶性质的研究

采用X-射线衍射仪对颗粒态抗性淀粉的结晶性质进行了研究.结果表明:原淀粉和粗抗性淀粉的结晶度和RS含量之间并不呈现一定的规律性,但各粗抗性淀粉样品结晶度都高于原高链玉米淀粉.对于相同处理工序(由酶和湿热处理)的粗抗性淀粉,随着高级微晶含量的增加,抗性淀粉RS含量增加.酶和湿热处理使高链玉米淀粉的晶型从B型转为A型.纯抗性淀粉随抗性淀粉含量的增加,结晶度增加.处理工艺相同的的纯抗性淀粉,随RS含量的增加,高级微晶含量和初级微晶含量都增加.在纯抗性淀粉中主要以A型结晶体为主.     

不同品种小米粉体外消化性的测定与分析

用α–淀粉酶和淀粉糖化酶酶解消化小米粉样品,采用3,5–二硝基水杨酸比色法(DNS)测定水解过程中产生的葡萄糖,对不同品种小米粉的体外消化特性进行比较,分析淀粉水解速率,快消化淀粉(RDS)、慢消化淀粉(SDS)和抗性淀粉(RS)含量,以及RDS、SDS、RS含量与直链淀粉含量的相关性。试验结果表明:复1、济12、市售的直链淀粉含量分别为1.96%、30.58%、35.58%;快消化淀粉(RDS)含量分别为87.18%、83.41%、80.73%;慢消化淀粉(SDS)含量分别为4.128 9%、8.72%、12.97%;抗性淀粉(RS)含量分别为8.69%、7.87%、6.31%。     

乳清蛋白及其水解物对马铃薯淀粉体外消化性和理化性质的影响

本文通过构建乳清蛋白及乳清蛋白水解物与马铃薯淀粉的共糊化体系来探究乳清蛋白及其水解物对马铃薯淀粉体外消化性和理化性质的影响。结果表明,经过胃蛋白酶和胰酶水解处理的乳清蛋白水解物对淀粉的消化率抑制效果最为明显。其中,天然马铃薯淀粉中快消化淀粉（RDS）含量最高（94.54%）,抗性淀粉（RS）含量最低（3.10%）。而经过胃蛋白酶处理后经胰酶处理120 min的样品中的RDS含量最低（67.51%）,RS含量最高（12.69%）。乳清蛋白水解物对马铃薯淀粉的溶胀和糊化的抑制作用均强于乳清蛋白。这说明乳清蛋白水解物的分子量对马铃薯淀粉的理化特性和消化性均有较大影响。此外,乳清蛋白及其水解物增强了体系中的氢键作用并提高了淀粉结构的有序程度,表明乳清蛋白及其水解物与马铃薯淀粉之间的相互作用会降低淀粉的消化性。     

糯米粉储藏过程中的消化性能

研究糯米淀粉的消化性能,与玉米淀粉、马铃薯淀粉和豌豆淀粉进行对比,研究发现,经过糊化后的淀粉比天然淀粉中的快消化淀粉(RDS)含量增加50%左右,而原先品种不同淀粉的慢消化淀粉(SDS)和抗性淀粉(RS)含量均会减少至10%左右,并且基本没有差异性。糊化后,糯米淀粉的RDS上升到最大,说明淀粉糊化后的消化性能和支链淀粉的含量呈负相关的关系。在短期储藏中,多数淀粉体系中的SDS和RS含量上升幅度均在5%左右,而RDS的含量下降幅度在10%。但糯米淀粉较特殊,因为在储藏早期影响淀粉消化性能的主要是直链淀粉,糯米淀粉主要含的是支链淀粉,支链淀粉的重结晶发生缓慢。所以,在储藏早期其对糯米淀粉消化性能的影响非常小,RDS、SDS和RS含量基本没有变化。     

山西谷子全粉淀粉指标间相关性及消化特性研究

本文主要研究了77个山西谷子全粉样品中淀粉组分的相关性以及淀粉消化特性。分别测定了谷子金粉中淀粉、直链淀粉和抗性淀粉(RS)含量。制备谷子淀粉并分析了淀粉中快速消化淀粉(RDS)、慢速消化淀粉(SDS)、RS的含量以及淀粉消化指数(SDI)和持续消化淀粉(LS)。结果表明:各品种间RS含量差异性较大;全谷物以及制备得到的淀粉所测定的备指标间相关性较强。其中。谷子中RS与直链淀粉相关性最强(r=0.885),对谷子中RS聚类分析后发现。RS与直链淀粉近似呈线性相关(r=0.954)。对谷子淀粉体外消化研究表明:黄谷(2010)等品种中SDS舍量较高,晋谷21号(2010)等品种中RS含量较高,而陇谷10号(2012)等品种中LS含量相对较高,这些品种适用于糖尿病等人群食用或有助于开发相关降糖产品。     

不同热处理下橡子淀粉理化性质和体外消化性分析

该研究系统比较了干热、预糊化、湿热处理后橡子淀粉理化性质和体外消化特性,结果表明：橡子淀粉表面光滑,主要为椭圆形、球形和不规则形状,粒径分布范围为0.42~26.30 μm,糊化温度为76.75 ℃,干热处理使水分子迁移和脱除,未涉及明确的淀粉糊化与回生,对橡子淀粉的颗粒形状、粒径大小、糊化温度和A型晶体结构等理化指标亦无显著影响;预糊化处理、湿热处理改变了原淀粉的颗粒结构和结晶类型,增大了淀粉颗粒尺寸,粒径分布范围为1.26~416.87 μm,淀粉颗粒变为不规则形状,表面粗糙,糊化温度降为50.17 ℃,ΔH、To、Tp、Tc、冻融稳定性显著降低（P<0.05）;橡子淀粉体外消化速率大小顺序为：干热处理>对照组>湿热处理>预糊化处理,抗性淀粉（RS）含量与之相反,预糊化处理RS含量最高,为38.21%,干热处理RS含量最低,为16.15%。本研究为橡子淀粉的深加工提供一定参考依据,有利于高品质橡子淀粉制品的开发。     

超微粉碎处理对木薯淀粉结构及消化特性的影响

为研究超微粉碎改性木薯淀粉及其对消化性的影响,以粒度分析、扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶红外分析(FT-IR)以及Englyst法为分析手段,研究木薯淀粉经过不同时间(0、15、30、45、60 min)超微粉碎处理后的粒度、微观结构及消化特性的变化。结果表明:木薯淀粉经超微粉碎处理60 min后,颗粒结构被严重破坏,淀粉颗粒之间发生团聚,淀粉粒径由13.50 μm增加至36.17 μm;超微粉碎处理对木薯淀粉的晶型没有影响,仍为A型,但其相对结晶度由21.33%下降至1.14%;木薯淀粉在3000~2800 cm-1与1080 cm-1处的吸收峰强度减弱,表明超微粉碎处理使木薯淀粉的结构遭到破坏,氢键相互作用减弱;天然木薯淀粉的快消化淀粉(RDS)、慢消化淀粉(SDS)、抗性淀粉(RS)的含量分别为3.91%、44.71%、51.38%,经过超微粉碎处理60 min以后,RDS与SDS的含量分别增加至6.87%和45.91%,RS的含量下降至47.21%,说明超微粉碎处理能够在一定程度上改变木薯淀粉的消化性。     

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.