球磨-酯化复合改性槟榔芋淀粉对Pickering乳液形成的影响

为了提高淀粉颗粒的乳化能力,以球磨-酯化复合改性槟榔芋淀粉为颗粒乳化剂,大豆油为油相,制备水包油型Pickering乳液.采用激光粒度仪、研究级正置显微镜、流变仪等对Pickering乳液外观、液滴粒径、显微形态及动态流变特性进行表征,考察淀粉颗粒质量浓度(1、5、10、20、30 mg/mL)和油相体积分数(10％、20％、30％、40％、50％)对乳液稳定性和流变特性的影响.研究发现:增加颗粒质量浓度导致乳化相体积增加,液滴粒径减小;随着油相体积分数的增加,乳化相体积增加,液滴粒径增大.当颗粒质量浓度为20 mg/mL,油相体积分数为40％时,乳液的乳析现象明显改善.球磨-酯化复合改性槟榔芋淀粉颗粒吸附在油/水界面,有效抵抗了液滴聚结,使乳液在储存30 d后仍表现出良好的稳定性.流变特性表明:乳液内部存在弹性凝胶网络结构,随着颗粒质量浓度和油相体积分数的增加,液滴间堆积变得更紧密,从而增加了乳液黏度和凝胶强度,使其抵抗形变能力增强.球磨-酯化复合改性槟榔芋淀粉颗粒具有良好的作为Pickering乳液稳定剂的潜力.     

基于大豆酶解聚集体制备Pickering乳液凝胶及环境稳定性分析

以大豆酶解聚集体（insoluble soy peptide aggregate,ISPA）制备Pickering乳液凝胶,在探索ISPA制备高油相乳液性质的基础上,对比分析模拟环境对乳液凝胶性质与稳定性的影响。结果表明：随着ISPA质量分数和油相体积分数增加,乳液粒径减小,凝胶强度增强,且以质量分数1.00%的ISPA和体积分数60%的油相制备的乳液展现出较强凝胶潜能;随后,将上述乳液凝胶置于不同NaCl浓度或酸性pH值下,发现乳液凝胶强度在高浓度NaCl或低pH值下仍有所增强,且经90 d常温贮藏或90 ℃加热60 min后粒径变化较小。综上,ISPA在新型Pickering稳定剂和食品配料开发中具有较大的加工应用潜能。     

小麦醇溶蛋白/卵磷脂复合纳米粒子制备Pickering乳液研究

以小麦醇溶蛋白和卵磷脂为原料,利用pH循环法制备小麦醇溶蛋白/卵磷脂复合纳米粒子,并以此为稳定剂制备Pickering乳液。探究了纳米粒子质量分数、油相体积分数对Pickering乳液的粒径、微观形貌、乳析稳定性、储藏稳定性及流变学特性的影响。结果表明：制备的Pickering乳液为水包油型乳液。当小麦醇溶蛋白/卵磷脂质量比为2∶1时,Pickering乳液的乳化活性和乳化稳定性分别为9.33 m²/g和93.33%。固定油相体积分数为50%,当纳米粒子质量分数由0.1%增加到2.0%时,Pickering乳液的粒径由56.19μm减小到36.57μm,乳析指数由46.5%增加到91.0%;固定纳米粒子质量分数为1.5%,当油相体积分数由20%增加到60%时,Pickering乳液的粒径由31.43μm增大到38.79μm,乳析指数由54%增加到93%。流变学结果表明,乳液的表观黏度和弹性性能随着纳米粒子质量分数以及油相体积分数的增加而增加,且都具有剪切稀化的现象,形成了凝胶网络结构;环境应力稳定性实验表明,Pickering乳液具有良好的NaCl离子稳定性。     

超细化豆渣作为皮克林乳液稳定剂的特性研究

将普通粉碎豆渣进行湿法超细化处理,研究超细化豆渣作为皮克林乳液稳定剂的特性,考察颗粒浓度、油相体积分数、pH及离子强度对乳液液滴尺寸、稳定性和流变学性质的影响。研究发现,超细化提升了豆渣颗粒的悬浮稳定性,且当油相分数φ=0.6,水相中豆渣颗粒质量分数≥0.4%时,形成皮克林乳液的粒径为80~140μm,在1~30 d存放期内乳析指数未发生显著变化。水相pH=7时乳液的粒径最大,pH降低时乳液的平均粒径呈单调递减,且乳液稳定性增强。水相中NaCl浓度在100~350 mmol/L对乳液粒径无显著影响。研究还表明,超细化豆渣稳定的皮克林乳液为剪切变稀型流体,其流变学特性受颗粒添加量及水相pH的影响。此研究表明,超细化豆渣具有良好稳定O/W型皮克林乳液的能力。     

大豆分离蛋白颗粒稳定的鲢鱼油Pickering乳液的制备及其性能表征

以鲢鱼鱼糜加工副产物鲢鱼油为油相,大豆分离蛋白（soy protein isolate,SPI）热聚集颗粒为稳定剂,构建SPI颗粒稳定的鲢鱼油Pickering 乳液体系,研究SPI 颗粒浓度（1.0%、1.5%、2.0%、2.5%、3.0%）、油相体积分数（0.1、0.2、0.3、0.4、0.5）、离子强度（0、0.1、0.2、0.3、0.4 mol/L）对Pickering 乳液的粒径、微观结构、流变特性、乳化特性、冻融稳定性等性能的影响。结果显示,SPI-鲢鱼油Pickering 乳液粒径呈多峰分布,当SPI 颗粒浓度增加,液滴粒径逐渐减小,乳化活性（emulsifying activity,EAI）逐渐降低;当SPI 颗粒浓度为2.5%时,乳化稳定性（emulsifying stability,ESI）最高,乳析指数（creaming index,CI）最低。当油相体积分数增高,液滴粒径变大,EAI 逐渐升高,ESI 逐渐降低;油相体积分数为0.3～0.5 时,冻融后的乳液CI 升高且伴有液态油析出。体系中加入氯化钠后,液滴粒径减小,粒度分布更加集中,液滴絮凝度升高,乳液稳定性增强;氯化钠浓度升高,粒径变大、EAI 先降低后升高,ESI 无明显差异。流变学特性分析表明,乳液的弹性模量大于黏性模量,乳液是以弹性为主的体系。结果表明,当SPI 颗粒浓度2.5%、鲢鱼油体积分数0.2及离子强度0.4 mol/L 时,SPI 颗粒稳定的鲢鱼油Pickering 乳液体系分布更加均匀,冻融稳定性更高。     

大豆分离蛋白-高酯柑橘果胶-没食子酸复合Pickering乳液制备及其稳定性分析

以大豆分离蛋白、高酯柑橘果胶、没食子酸为原料,制备一种蛋白质-多糖-多酚复合物,利用单因素试验、正交试验优化复合物制备条件,并通过流变特性、粒径及分布、Zeta电位、乳液稳定性等分析手段对Pickering乳液稳定性能进行表征。结果表明：在pH 4.5、温度35 ℃、没食子酸含量40 mg时复合乳液的吸光度达到最大值3.082,此时大豆分离蛋白-高酯柑橘果胶-没食子酸结合最紧密;当油相体积分数为0.7时,Pickering乳液弹性和黏性最好,形成的较好凝胶网络结构,此时的电位为（－54.08±2.74）mV,平均粒径为（220.36±7.13）nm;与25 ℃常温贮存相比,Pickering乳液在4 ℃冷藏析乳现象更弱,油滴粒径变化更小,更有利于维持乳液稳定性;随热处理温度升高,乳液析乳情况逐渐增强,油相体积分数为0.7和0.8时,液滴粒径受温度变化不明显;冷冻会破坏复合物形成的界面层,随着油相体积分数升高和冷冻时间的延长乳液析油现象明显导致稳定性大大降低;随着pH值升高,析油现象逐渐明显,当乳液体系pH值接近4时,乳滴粒径最小且分布相对均匀;高浓度的盐离子会破坏复合物结合的紧密程度,液滴发生聚集,乳液析乳情况明显,稳定性下降。     

肉桂酸基油凝胶及其乳液的制备及理化性质表征

选择玉米油为溶剂,肉桂酸为凝胶剂制备油凝胶,探究其流变学、质构、持油性、热力学特性及凝胶剂晶体形态;以油凝胶为分散相,制备油凝胶乳液（O/W型）,分析其粒径、流变学、稳定性等物理性质。结果表明：肉桂酸临界成胶质量分数为4%,4?℃条件下存放的油凝胶持油性较常温条件下更好;肉桂酸质量分数越大的油凝胶硬度越大,热稳定性越好;肉桂酸在油凝胶中呈现随机分布的长纤维状聚集体;油相质量分数为10%～20%时,油相含量越低,其乳液粒径越小、黏度越低、物理稳定性越好。油凝胶在常温下稳定性较差,而油凝胶乳液在常温下能保持良好的稳定性,有益于其在食品工业领域的研发与应用。     

脱脂芝麻粕稳定高内相乳液的制备及特性

分别以去皮和带皮脱脂芝麻粕为稳定剂制备了高内相乳液(HIPEs),研究了该乳液的基本性质,探讨了脱脂芝麻粕添加量、油相体积分数、体系pH以及离子浓度对HIPEs微观结构、粒径及流变性质的影响。结果表明:油相体积分数为0. 75时,去皮和带皮脱脂芝麻粕稳定HIPEs的最低添加量分别为5. 0%和3. 0%;去皮和带皮脱脂芝麻粕添加量为5. 0%时,其稳定HIPEs的最高油相体积分数分别为0. 75和0. 85;脱脂芝麻粕在中性pH以及添加适量NaCl下,制备的HIPEs更稳定。流变性质研究表明,HIPEs内部存在以弹性为主的凝胶网络结构,随着脱脂芝麻粕添加量的增大,HIPEs粒径逐渐减小且呈均匀分布,黏弹性能逐渐增大。     

大豆蛋白稳定乳液油凝胶的制备及其在肉糜中的应用

以大豆蛋白为稳定剂,葵花籽油为油相,通过高速剪切乳化技术制备乳液油凝胶,研究载油量、大豆蛋白浓度和热处理时间对乳液油凝胶的影响,并将乳液油凝胶应用于肉糜中替代动物脂肪。结果表明：大豆蛋白颗粒可以承载体积分数达70%的油相,且在大豆蛋白浓度超过1%的条件下,能形成稳定的乳液油凝胶,其粒径随着大豆蛋白浓度的增加而略微变小。乳液油凝胶经80 ℃热处理后,粒径大小随加热时间基本不变,显示良好的热稳定性。流变分析表明乳液油凝胶的黏度随剪切速率升高而下降,不同加热时间下的储能模量均比损耗模量高,表明乳液形成了弹性的类凝胶网络,且加热处理45 min 的乳液油凝胶黏弹性最为突出。肉糜经高温蒸煮后,肉糜蒸煮得率随乳液油凝胶替代比例的升高而提高,当乳液油凝胶完全替代猪油脂时,油脂和水分的渗出率明显降低。     

南瓜籽油乳液的制备及稳定性

采用高压均质法,以乳清分离蛋白为乳化剂制备南瓜籽油乳液,对均质压力、均质次数、乳化剂添加量以及南瓜籽油质量分数对南瓜籽油乳液粒径、多分散系数（PDI）、Zeta电位和分光比（SRI,800 nm下吸光度与400 nm下吸光度的比值）的影响进行考察,并研究了南瓜籽油乳液的稳定性。结果表明：南瓜籽油乳液的最佳制备工艺条件为均质压力50 MPa、均质次数5次、乳化剂添加量2.5%、南瓜籽油质量分数10%,在最佳工艺条件下,南瓜籽油乳液的粒径为（213.33±5.60）nm,PDI 为0.215±0.002,Zeta电位为（-5680±0.66）mV,SRI为 0.27±0.02;在15 d的室温储藏期间内南瓜籽油乳液具有较好的物理稳定性和较高的氧化稳定性。     

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.     

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.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.