β-谷甾醇/γ-谷维素和月桂酸单甘油酯对蜂蜡山茶油油凝胶结构性质的影响

目的 探究基于蜂蜡(beeswax, BW)的复配凝胶剂对山茶油凝胶结构性质的影响。方法 以山茶油为基料油, 以蜂蜡为基本凝胶剂, 添加β-谷甾醇/γ-谷维素(β-sitosterol/γ-oryzanol)和月桂酸单甘油酯(glyceryl monolaurate, GML)来制备蜂蜡-β-谷甾醇/γ-谷维素(beeswax-β-sitosterol/γ-oryzanol, BSO)和蜂蜡-月桂酸单甘油酯(beeswax-glyceryl monolaurate, BGM)复配山茶油油凝胶, 并测定其色度、微观形态、晶体结构、热力学性质和硬度。结果 色度分析表明随着添加量增大, BSO复配油凝胶的颜色变化较显著, BGM复配凝胶的颜色则无明显差异。微观形态观察和硬度分析表明BSO复配油凝胶的晶体网络结构更为疏松,BGM复配油凝胶的网络空隙变大,两者硬度都远低于蜂蜡油凝胶的硬度。晶体结构分析表明随着添加量增大,BSO和BGM复配油凝胶中α晶型逐渐转变为β晶型。热性能分析表明BSO和BGM复配油凝胶的熔点和结晶点低于蜂蜡油凝胶。结论 BSO和BGM复配使蜂蜡油凝胶的性能得到一定改善,在提高油凝胶的应用价值方面具有重要意义。     

急冷温度及凝胶剂添加量对植物甾醇/谷维素油凝胶物理特性的影响

为促进植物甾醇/谷维素油凝胶在零反式、低饱和的营养型塑性脂肪中的应用,以大豆油为基料油,植物甾醇/谷维素为凝胶剂,在不同急冷温度(5、20℃)及凝胶剂添加量下制备油凝胶,测定不同急冷温度及凝胶剂添加量下植物甾醇/谷维素油凝胶的晶型、晶体形态、物理稳定性、质构和热力学特性的变化。结果表明：随着凝胶剂添加量的升高,油凝胶中晶体排列逐渐致密,硬度增大,熔点升高;尽管急冷温度对油凝胶的晶型(β晶型)没有明显影响,但相对于5℃急冷,20℃急冷得到的油凝胶晶体组装更为致密,物理稳定性增强;在与传统甘三酯固脂对比SFC与硬度和熔点的关系中发现,在油凝胶体系中熔点随SFC的增加呈现非线性关系增长,但低固体脂肪含量(4.85%)即可赋予植物甾醇/谷维素油凝胶较高的硬度。综上,急冷温度及凝胶剂添加量对植物甾醇/谷维素油凝胶的物理特性具有显著的影响。     

单甘酯与蜂蜡复配制备五步蛇蛇油基凝胶油的研究

以五步蛇蛇油为基料油,通过向其添加不同质量比的蜂蜡与单甘酯制备凝胶油。探讨不同蜂蜡与单甘酯的质量比对五步蛇蛇油基凝胶油流变性、持油性以及硬度的影响,并对其结晶型态、结晶形状进行分析。结果表明:少量单甘酯的存在(蜂蜡与单甘酯质量比8∶2)降低了五步蛇蛇油基凝胶油的黏度恢复值及硬度,促进凝胶油长枝状结晶的生成,增加α、β以及β'型晶体;随着单甘酯比例的进一步增加(蜂蜡与单甘酯质量比8∶2～0∶10),五步蛇蛇油基凝胶油析油率和黏度恢复值增加,长枝状结晶逐渐变短至消失,α型晶体逐渐消失;确定蜂蜡与单甘酯质量比4∶6为最佳比例,此时五步蛇蛇油基凝胶油的析油率为1. 8%,硬度为242 g,黏度恢复值为37%。     

γ-谷维素/β-谷甾醇与单硬脂酸甘油酯复合凝胶油的制备及性能研究

以食用棕榈油为基料油,添加分子蒸馏单硬脂酸甘油酯与γ-谷维素/β-谷甾醇制备复合凝胶油。在单因素试验的基础上,应用响应面法优化复合凝胶油的制备条件。探讨凝胶剂比例对凝胶油性能及微观结构的影响,分析γ-谷维素/β-谷甾醇在复合凝胶油形成过程中的作用。结果表明:最优制备条件为复合凝胶剂添加量9.89%、复合凝胶剂中γ-谷维素/β-谷甾醇占比52.3%、γ-谷维素与β-谷甾醇质量比3∶2、加热时间41.7 min,在此条件下复合凝胶油持油性可达94.6%。γ-谷维素/β-谷甾醇的添加对复合凝胶油热力学性质、流变学性质和红外光谱特征均产生了较大影响。在复合凝胶油中γ-谷维素/β-谷甾醇与单硬脂酸甘油酯存在范德华力等弱的非氢键作用,使得单硬脂酸甘油酯和γ-谷维素/β-谷甾醇协同形成复合凝胶油。随着单硬脂酸甘油酯含量的增加,系统内氢键作用逐渐减小直至消失,微观结构由纤维网状先转换为球状结晶,最后为针状结晶。复合凝胶油的熔点和结晶点低于单一凝胶油,黏性和刚性较小。     

植物甾醇+γ-谷维素型凝胶油的制备及其影响因素的研究

以米糠油为油溶剂制备植物甾醇+γ-谷维素型凝胶油,采用流变仪、质构仪、X-射线衍射仪和偏振光显微镜分别研究了凝胶油的流变性、硬度、脆性、晶型、晶体形态等。结果表明:植物甾醇与γ-谷维素质量比为40∶60时所形成的凝胶油硬度最大,熔点最高,脆性最小;随着植物甾醇与γ-谷维素添加量的增大,凝胶油硬度和熔点随之增大,脆性随之减小;甾醇酯和植物甾醇不能使体系凝胶化,甾醇酯的存在会表现出拮抗性,阻碍凝胶的形成,凝胶油的硬度、黏度随着甾醇酯添加量的增加而减小,脆性和熔点则随着甾醇酯添加量的增加而增大,其次,凝胶形成的时间随着甾醇酯添加量的增加而延长;冷却过程中施加一定的剪切会降低凝胶体系的硬度、黏度和熔点,脆性增大;植物甾醇+γ-谷维素型凝胶油为β-晶型,随着储藏时间的延长,其中的纤维网络结构逐渐形成并聚集延伸。     

β-谷甾醇与γ-谷维素键合特征的红外光谱分析

建立了傅里叶红外光谱法表征β-谷甾醇与γ-谷维素键合特征的方法.在红外图谱中可以看出,β-谷甾醇的羟基伸缩振动峰明显向低波数移动,并导致谱带变宽,γ-谷维素的羰基吸收峰也出现向低波数位移,说明β-谷甾醇与γ-谷维素之间产生了分子间的氢键效应.当β-谷甾醇与γ-谷维素质量比为2∶3时氢键效应最强,并且质构和锥入度分析表明其硬度也最大.β-谷甾醇与γ-谷维素的油脂样品在偏振 光显微镜下呈现四瓣形的自组装新晶体.     

谷维素/谷甾醇与单甘酯复合凝胶油形成过程及分子作用特性

以谷维素/谷甾醇和单甘酯为凝胶剂,葵花籽油为原料油制备复合凝胶油,探讨复合凝胶油的形成过程以及单甘酯对凝胶化过程的影响,实验发现凝胶油的形成可分为3?个阶段,在凝胶剂到达过冷、过饱和的平衡阶段,受单甘酯影响较小;在凝胶剂分子聚集成核的对数阶段,单甘酯会增加单位体积焓值,降低总吉布斯自由能,促进成核;而在晶体生长、组装的线性阶段,逐渐形成凝胶油的一级、二级、三级结构,其中三级结构与宏观特性最为紧密,三级结构中永久交联和瞬时交联的比例决定了凝胶油的主要性质。通过核磁分析表明物理截留油是凝胶化植物油的主要机理,在此基础性上通过X-射线衍射和小角X-射线散射分析了凝胶剂的组装结构,结果表明谷维素/谷甾醇凝胶油形成的为六边对称结构,单甘酯凝胶油形成的为层状对称结构,同时含有谷维素/谷甾醇和单甘酯的复合凝胶油为立方对称结构。     

分子蒸馏单甘酯对谷维素-谷甾醇凝胶油结构和性质的影响

以精炼葵花籽油为基料油,添加分子蒸馏单甘酯与谷维素-谷甾醇制备复合凝胶油,探讨凝胶剂分子间比例对凝胶油结构和性质的影响,以分析单甘酯在复合凝胶油形成过程中的作用。结果表明：在复合凝胶油中单甘酯会与谷甾醇存在着范德华力等弱的非氢键作用力,使得单甘酯和谷甾醇在临界凝胶浓度下,协同形成复合凝胶油。单甘酯的添加对复合凝胶油热力学性质和流变学性质等宏观特性均产生较大影响,添加单甘酯后复合凝胶油微观结构和红外光谱产生了显著变化,随着单甘酯含量的增加,氢键作用逐渐减小直至消失,而微观结构由纤维网状到球状结晶最后为针状结晶;结果还表明添加单甘酯后凝胶油氧化更慢,利于长期贮藏。     

油茶籽油基复合油凝胶的制备工艺研究

以油茶籽油为基料油,通过添加单甘酯与蜂蜡制备复合油凝胶,探讨复合凝胶剂添加量、单甘酯与蜂蜡质量比、加热温度以及加热时间对油茶籽油基复合油凝胶持油性的影响。在单因素试验的基础上,采用Box-Behnken试验设计方法优化试验条件,并对复合油凝胶体系的性质进行分析。结果表明,油茶籽油基复合油凝胶的最优制备工艺条件为:复合凝胶剂添加量9.9%,单甘酯与蜂蜡质量比4∶6,加热温度71℃,加热时间47 min。在最优工艺条件下,复合油凝胶持油性为98.70%,体系中存在α、β、β'3种晶型,并且与单一凝胶剂油凝胶相比,油茶籽油基复合油凝胶具有较好的持油性和适中的硬度。     

葵花籽油凝胶油的制备及其在冰淇淋中的应用

以葵花籽油为原料,添加一定量的蜂蜡或蜂蜡与谷维素混合物制备葵花籽油凝胶油,研究不同添加量的凝胶因子对葵花籽油凝胶油的硬度值、黏度值、持油性和微观形态的影响;将得到的凝胶油代替黄油制备冰淇淋,研究其在冰淇淋中的应用。结果表明:蜂蜡添加量对凝胶油的质构特性、持油性和微观形态影响较为显著,并确定5%蜂蜡添加量为凝胶油制备的最优条件;添加5%复合凝胶油(5%蜂蜡+1%谷维素)和5%黄油制备的冰淇淋营养丰富、抗融性好、色泽均匀、组织细腻、滑润爽口,与添加10%黄油制备的冰淇淋较为相近,表明可以通过进一步的优化代替饱和脂肪在冰淇淋中应用。     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the