食品级皮克林乳液制备及应用研究进展

食品级皮克林乳液是依靠多糖、蛋白质等可食性固体颗粒对油水界面稳定制备的乳液。与传统乳液相比,食品级皮克林乳液具有抗聚结,稳定性好和制备简易等特点,在食品加工应用方面存在潜力。本文依据皮克林乳液的稳定机理介绍影响其稳定性的因素;依据食品级皮克林颗粒的种类综述皮克林乳液的制备方法,总结其在食品中的应用,并探讨其发展方向。     

食品级皮克林乳液的稳定机制及稳定性研究进展

本文综述了皮克林乳液的稳定机制,降解机制,稳定性调控以及皮克林乳液在食品行业的应用。皮克林乳液的稳定机制是通过胶体颗粒吸附在油水界面上,胶体颗粒形成固体网状结构以及形成较低程度的絮凝来稳定的。皮克林乳液的降解机制分为物理降解和化学降解,包括絮凝,聚集,沉淀,奥氏熟化以及脂质氧化等现象。现今常用来调控皮克林乳液稳定性的手段包括:粒子修饰,多种物质协同稳定,调节环境因素,调节粒子浓度等手段。本文旨在为研究皮克林乳液的稳定机制,降解机制以及在食品行业的应用提供一定的理论参考,从而扩大其在食品领域的应用范围。     

小麦醇溶蛋白纳米颗粒稳定皮克林乳液的研究

目的 构建负载丁香酚的小麦醇溶蛋白/果胶纳米颗粒稳定皮克林乳液,提高丁香酚生物利用率。方法 通过反溶剂法制备复合纳米颗粒,以乳液粒径、乳析指数为指标,考察复合纳米颗粒对皮克林乳液稳定性影响;以抑菌率为指标,考察皮克林乳液中丁香酚的生物利用率。结果 当负载丁香酚的小麦醇溶蛋白/果胶纳米颗粒浓度达5.00%,油相比例不超过60%,盐离子浓度低于250 mmol/L,储藏时间60 d以内时:皮克林乳液液滴颗粒分散,体系较为稳定。与此同时,当皮克林乳液最小抑菌浓度为1.00 mg/mL时,可有效抑制大肠杆菌的生长。结论 负载丁香酚的小麦醇溶蛋白/果胶纳米颗粒可在油水两相间形成界面膜以稳定皮克林乳液,其抑菌性能通过延长食品货架期的形式应用于食品保鲜领域中。     

皮克林乳液冻融稳定性研究进展

皮克林（Pickering）乳液冻融稳定性是指皮克林乳液经历冻融循环过程后仍保持其相对稳定的特性。近年有关皮克林乳液冻融稳定性的研究日渐深入,研究提出Pickering乳液具有粘弹性层和凝胶网络结构可有效地阻挡由冰晶产生的应力作用对乳液结构造成的破坏,具有良好的冻融稳定性。目前,Pickering乳液常作为活性物质包埋剂、食品包装材料和脂质替代品广泛应用于食品方面,因此具有冻融稳定性的皮克林乳液有着潜在的商业价值。冻融稳定性的影响因素较多,主要有温度、离子强度、颗粒组成、修饰技术以及制备技术等。本文综述了皮克林乳液的冻融稳定性相关机制及影响冻融稳定性因素的研究进展,随着Pickering乳液在食品以及各个领域中应用逐渐发展,基于分子层面揭示Pickering乳液冻融稳定性相关机制将更深一步引起人们的研究兴趣。     

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。     

光催化纳米二氧化钛材料及其应用

皮克林（Pickering）乳液是一种由固体颗粒代替传统乳化剂形成的新型乳液体系,具有稳定性强、对环境友好、安全性高等天然优势,在食品、化妆品、化工材料、生物医药等多个领域一直备受青睐。本文阐述了Pickering乳液的稳定机制,在其基础上从六个方面主要讨论影响Pickering乳液稳定性的相关因素,分别为固体颗粒的类型、形状、浓度、表面电荷、油水相体积分数及湿润性;同时,总结了近几年Pickering乳液用于制备智能食品薄膜、防止脂质氧化、递送生物活性物质、合成分子印迹聚合物、实现双相催化、构建4D打印食品原材料的国内外研究成果,旨在为食品工业及其他相关领域的多元化发展提供理论依据和技术支撑。

     

食品级固体颗粒稳定Pickering乳液机制的探讨

Pickering乳液是一种由固体颗粒分散,稳定于水相和油相的乳液。食品级固体颗粒采用多糖、蛋白质与多酚复合形成用于稳定Pickering乳液。文章从食品级固体颗粒的分类与制备方法,论述固体颗粒结合机制与Pickering乳液的应用,并从构成Pickering乳液固体颗粒、水相和油相三方面因素对乳液稳定性的影响进行综述,分析产生Pickering乳液类型。由食品级固体颗粒的湿润性(接触角)、尺寸及形状、表面电荷和颗粒的浓度,水相的pH值与盐离子浓度,油相的种类和体积分数,论述阐明Pickering乳液的稳定机制。最后对食品级Pickering乳液的应用及其发展趋势给予展望,为食品级Pickering乳液的研究前景提供思路。     

光催化大豆蛋白纳米颗粒皮克林乳液的制备及稳定性研究

利用光催化技术使大豆蛋白自组装形成纳米颗粒,并以此制备皮克林乳液。研究光催化时间对颗粒自组装形成过程的影响,并对乳液分别进行粒径分布、乳析指数、离心稳定性和贮藏稳定性的测定。结果表明,随着光催化时间的延长,蛋白颗粒的粒径增加,PDI值减小,疏水性增强,Z电位增大。当光催化时间超过30 min时,PDI值增大,疏水性减弱,Z电位降低。颗粒间主要以疏水作用和二硫键来维持光催化大豆蛋白颗粒稳定性。与大豆蛋白乳液相比,光催化大豆蛋白颗粒稳定的乳液表现出良好的贮藏稳定性和离心稳定性。利用激光共聚焦显微镜观察发现,皮克林乳液具有更高的界面蛋白吸附量和较厚的界面膜。光催化大豆蛋白颗粒有望成为食品级皮克林稳定剂的有效材料。     

大豆纤维稳定水包油型皮克林乳液的研究

近年来,由于食品级皮克林乳液在开发新型功能食品方面表现出潜在应用价值,关于食品级皮克林乳液的稳定剂的研究备受关注。本文主要研究了大豆纤维稳定玉米油的水包油型皮克林乳液的性质,通过测定ζ-电势、显微结构、乳液粒径变化、乳析指数、离心稳定性,分析了大豆纤维浓度(c;0.125%~1.0%,m/m)和油相质量分数(Φ;10%~40%,m/m)对乳液稳定性的影响。结果表明:Φ=10%时,随着大豆纤维的浓度增加乳液的粒径增大,絮凝程度增加,抗聚集稳定性和抗分层稳定性增强;c=0.75%时,随着油相质量分数增加乳液粒径显著增大,乳液稳定性迅速下降,且有明显油析现象出现。研究结果表明大豆纤维作为皮克林乳液的稳定颗粒有良好的潜力,对进一步深入研究大豆纤维稳定的皮克林乳液有指导意义。     

食品级凝胶颗粒的制备及应用研究进展

凝胶颗粒是具有颗粒形态的微凝胶大分子物质,由大分子聚合物交联形成,微观上具有三维网络结构。凝胶颗粒具有稳定的网络结构,可以分散在溶液中,在宏观上具有流体力学性质。凝胶颗粒的制备可通过挤压法、喷雾干燥法、剪切法以及高压均质法等机械方法对凝胶或胶体颗粒溶液进行分离、破碎,得到含有微米或纳米级凝胶颗粒的溶液。因其兼具凝胶性质和流体力学性质,故可以对功能因子进行包埋和保护。凝胶颗粒具有良好的稳定性,可以作为乳液中的稳定剂制成皮克林乳液。本文概述了凝胶颗粒的种类以及国内外几种常用的机械制备方法,简述了其目前在食品工业中的应用状况,为进一步研究凝胶颗粒在食品领域中的应用拓展奠定基础。     

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.     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Detection of adulteration of locust bean gum with guar gum by capillary electrophoresis and polarized light microscopy

Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH₃CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH₂PO₄-20.6 mM Na₂B₄O₇ buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.