激光共聚焦显微镜分析技术在食品体系微观结构领域应用研究进展

本文介绍了激光共聚焦扫描显微镜原理,并对其在食品体系结构研究中的应用概况进行综述。此技术可对食品体系微观结构进行三维重建,弥补了传统光学扫描电镜只能二维成像的缺陷。     

干酪微观结构观察方法与研究进展

综述了干酪微观结构分析常用的两种显微镜技术。第一,光学显微镜(LM)技术,包含明视野显微镜、偏振光显微镜、荧光显微镜和共聚焦激光扫描显微镜技术;第二,电子显微镜(EM)技术,包括扫描电子显微镜和透射电子显微镜技术,并对其优缺点和样品前处理简要流程做了阐述。     

显微技术在纸张三维结构表征中的应用

纸张三维结构即各组分在空间结构中的分布,对纸张性能具有重要影响。表征纸张三维结构有助于全面了解纸张结构与性能的关系。随着显微技术不断发展,其在表征纸张结构上的应用越来越多,进而为揭示纸张结构与性能间关系提供了重要途径。对显微技术在纸张三维结构的应用进行了概述,重点介绍了光学显微镜、扫描电子显微镜、激光共聚焦显微镜及X射线微米CT技术在表征纸张三维结构上的应用,并比较了它们的优缺点。     

原子力显微镜在食品研究中的应用

原子力显微镜(AFM)是20世纪80年代开始新兴并得到迅速发展的现代显微技术.本文简介了原子力显微镜的基本原理及其优点,着重介绍了AFM技术在食品研究领域的应用,阐述了其在多糖分子、蛋白质分子及其凝胶、结晶结构,淀粉颗粒纳米微观形貌和界面等方面的研究发现和成果,表明AFM非常适于食品组织体系在保持原生态或者不同状态条件下进行显微观察和研究,具有高清晰度、高分辨率,能够探测细微结构特征等特点,是一种具有发展潜力和广泛应用前景的显微技术.     

EGCG修饰对乳清蛋白乳液冷凝胶特性的影响

研究不同浓度表没食子儿茶素没食子酸酯(EGCG;2.7,13.3,26.6μmol多酚/g蛋白质)对乳清蛋白乳液冷凝胶微观结构及凝胶特性的影响.采用动态光散射和凯氏定氮法测定乳液的粒径、带电性质和界面蛋白吸附量,激光共聚焦显微镜观察乳液微观结构,分析EGCG对蛋白乳液微观结构和特性的影响.采用质构仪单轴压缩法测定凝胶强...     

食品乳状液稳定性检测方法研究进展

文章综述了食品乳状液稳定性的七种检测方法,包括光学法(激光粒度仪法、Turbiscan法、Lumisizer法、透射光浊度法)、电荷分布法、流变法、界面吸附法、微观结构法(显微镜观察法、原子力显微镜法、透射电子显微镜法)、高速离心分析法、直观观察法。结合实例,分析七种检测方法在食品乳状液体系中的应用。为乳状液在食品领域中的研究与应用提供了方法指导。     

油炸工艺对高油酸花生品质与微观结构的影响

研究植物油种类、油炸温度、油炸时间对油炸花生感官品质、质构特性的影响，并通过激光共聚焦扫描显微镜(CLSM)和扫描电镜(SEM)观察油炸前、后花生微观结构的变化。结果表明，油炸最佳工艺条件:植物油种类为棕榈油，油炸温度140 ℃、油炸时间8 min。在该工艺条件下油炸花生色泽均匀，口味香甜，口感酥脆，硬度7.30 kg，脆性0.27 mm，感官得分48.9，水分含量0.87 g/100 g、酸价1.20 g/100 g、过氧化值0.09 g/100 g，扫描电镜与激光共聚焦显微镜观察的结果一致，花生在油炸后细胞壁断裂，细胞质丢失，出现孔状结构，细胞内油体增加，蛋白体聚集。     

纤维的表面性能及表面分析技术

阐述了纤维表面性能的重要性,并主要介绍了扫描电镜(SEM)、透射电镜(TEM)、原子力显微镜(AFM)、激光共聚焦扫描显微镜(CLSM)、X射线光电子能谱(XPS)、二次离子质谱(SIMS)等现代表面分析技术及其在制浆造纸研究中的应用.     

黄原胶对大豆蛋白营养棒体系质地及微观结构的影响

通过质构仪、激光共聚焦显微镜、电子扫描显微镜和低场核磁共振技术等手段,研究了添加1%黄原胶对含有大豆蛋白的营养棒模型体系质构、微观结构、水分子及亲水小分子的迁移等的影响。结果表明:黄原胶的添加改变了体系微观网状结构,同时影响了体系内水及糖醇等小分子的分布,从而对大豆蛋白模型体系的质构有明显的软化效果,改善其质构和口感。     

研究速递

芬兰开发出高精度手机显微镜模块芬兰国家技术研究中心开发出一种可用于手机、具有拍照功能的显微镜模块,使手机成为高精度显微镜。该发明是在手机摄像头处嵌入多个发光二极管,形成三维成像技术,将显微镜头贴在手机镜头上,无球面透镜成像和三维成像相结合,即能使手机成为高效显微镜。该显微镜可显示各种物体表面和结构的微观细节,分辨率可达10μm。     

Wheat Dough Microstructure: The Relation Between Visual Structure and Mechanical Behavior

The microstructure of food matrixes, and specifically that of wheat-flour dough, determines mechanical behavior. Consequently, the analysis of such microstructure is both necessary and useful for understanding the physico-chemical and mechanical alterations during the production of cereal-based products such as breads. Confocal laser scanning microscopy (CLSM) is an established tool for the investigation of these matrix properties due to its methodical advantages such as easy preparation and handling, and the high depth resolution due to the optical sectioning of probes. This review focuses on the microstructure of wheat-flour dough from a mechanical and visual point of view. It provides an overview of the dependencies between the visibly detectable microstructural elements achieved by CLSM and the physical determined rheological properties. Current findings in this field, especially on numerical microstructure features, are described and discussed, and possibilities for enhancing the analytical methodology are presented.     

抗冻剂对速冻南瓜泥品质影响及其机理探究

为研究果胶、胶原肽及海藻糖组成的新型复配抗冻剂对速冻南瓜泥品质的影响并探究其机理,以析水率、粒径、Zeta电位值表征产品稳定性,采用质构特性、色度、可溶性固形物含量评价产品品质,并结合扫描电子显微镜与激光扫描共聚焦显微镜观察样品微观结构。结果显示,抗冻剂可显著减缓冻藏过程中速冻南瓜泥的析水率、平均粒径的升高趋势,以及L*、a*、b*、硬度、内聚性、可溶性固形物含量、Zeta电位绝对值的降低趋势,并且能够有效保护速冻南瓜泥的超微结构,使大分子分布均匀。     

La microscopie confocale: interet pour l'analyse du relief cutané. Un outil d'évaluation dermo-cosmétique

Nowadays, the determination of human skin microtopography is usually carried out by methods based on mechanical techniques (profilometry and surfometry), or founded on optical conception (shadowing method and profilometry). Negative skin replicas made of a silicone rubber material (Silflo((R))) or positive casts performed from an epoxy resin (Araldite((R))), are used to assess the skin microstructure. Skin surface microtopography is quantified by measuring furrows depths and spaces between them. An original application using confocal scanning laser microscope (CLSM) is described in this paper. The CLSM gives simultaneously images of the skin surface associated with quantitative measurements of the microtopography. With this apparatus, it is easy to achieve perfect skin replica images with assessment of its microstructure, before and after applications of topical medicines or cosmetic products to evaluate the skin surface restoration. It is worth to mention that it is indispensable to analyse the same skin surface (same plateaux and same furrows). For this reason, it is necessary to localize exactly and to replicate the same skin surface area (4 mm(2)) before and after the cosmetic use, whatever the extended period of the topical application.     

Implementation of a novel tool to quantify dough microstructure

A method was developed to quantify the microstructure of wheat dough proteins assessed by a confocal laser scanning microscope (CLSM) in combination with an image processing and analyzing tool. A variation of the water addition especially showed high significant (p<0.01) linear correlations with the branching index (r=-0.92). This branching index exhibited high significant correlation coefficients with the rheological measures complex shear modulus (r=0.88), creep compliance (r=-0.71) and relative elastic part (r=0.82). In summary the results submit a novel view on the microstructure of dough. The obtained visual structure of the dough via CLSM in combination with image processing and analyzing has proven to be a reliable and powerful tool for the acquisition and validation of dough protein microstructure. The high dependency of rheology from structural elements could be verified.     

高压均质对玉米淀粉机械力化学效应研究

以玉米淀粉为原料,通过扫描电镜(scanning electron microscope,SEM)、X-射线衍射(X-ray diffraction,XRD)、激光共聚焦显微镜(confocal laser scanning microscopy,CLSM)、快速黏度分析仪(rapid visco analyser,RVA)、差示扫描量热仪(differential scanning calorimetry,DSC)、偏光显微镜(polarizing microscope,PLM)等手段研究高压均质处理对玉米淀粉微观结构及理化性质的影响,揭示高压均质对玉米淀粉机械力化学效应。结果表明,高压均质对淀粉颗粒的无定形区、结晶区产生很强的机械力化学作用,推断淀粉颗粒内部依次发生了聚集和团聚效应。     

Microscopic structure,viscoelastic behaviour and 3D printing potential of milk protein concentrate-hydrocolloid complex coacervates

To prepare a milk protein-enriched ink for extrusion-based 3D food printing, this study investigated the effects of a wide range of hydrocolloids on the microstructures, viscoelastic characteristics and 3D printing performance of milk protein concentrate (MPC). The distributions of hydrocolloids and milk protein in mixed coacervates were characterised by fluorescent covalent labelling and confocal laser scanning microscope (CLSM), and the microstructure of the coacervates was observed by scanning electron microscopy (SEM). In addition, the rheological properties of prepared protein coacervates, including steady shear test, dynamic oscillatory test, thixotropy and creep recovery were investigated. Meanwhile, Burger’s model was fitted to the creep behaviour to further study their viscoelastic properties. The results showed that κ-carrageenan, pectin, guar gum and sodium alginate significantly increased the zero-shear viscosity, thixotropy and solid-like behaviour while xanthan showed an opposite phenomenon. Results showed that the presence of hydrocolloids improved the 3D printability of MPC by forming a complex network between protein particles and hydrocolloids, and guar gum, pectin and κ-carrageenan better help maintain the deposited 3D structures of MPC ink than xanthan.     

Comparing techniques for detecting the number of somatic cells in raw milk

Evaluating the quality of milk and monitoring for cow mastitis requires an evaluation of the somatic cell count (SCC), an important parameter in the dairy industry. We studied the somatic cells of raw milk using a confocal laser scanning microscope (CLSM), flow cytometry (FCM), and a light microscope (LM). The CLSM method gave a good correlation (r=0.987) with the LM counts of somatic cells in raw milk. The FCM method also correlated well (r=0.904) with the LM method. The CLSM method gave a good correlation (r=0.908) with the FCM method. This study shows that the CLSM method and the FCM method both offer rapid and simple approaches to somatic cell detection.     

Influence of Different Cations on Chemical Composition and Microstructure of Pidan White and Yolk During Pickling and Aging

Effects of different cations on chemical composition and microstructure of pidan white and yolk were investigated. During 3 weeks of pickling and further 3 weeks of ageing, ammonia and ash contents were increased but varied with types of cations used. Lower protein degradation of pidan white was observed in pidan treated with 0.2% PbO₂, compared with other treatments. Scanning electron microscopic (SEM) studies indicated that the greater aggregation of egg proteins took place in pidan white treated with PbO₂. Yolk of pidan treated with 0.2% PbO₂ had more release of free lipid as visualised by confocal laser scanning microscope (CLSM).     

酸法脱酰胺大米蛋白/葡聚糖体系微结构性质研究

研究了酸法脱酰胺大米蛋白(ADRP)/葡聚糖混合体系的微观结构及流变性质。采用共聚焦激光扫描显微镜观察了ADRP/葡聚糖混合体系的微观结构,结果显示出ADRP之间产生了有效的交联,并且在蛋白质质量分数较高的混合体系中形成了蛋白质网状结构。流变仪观察了混合体系的动力学性质,黏度-剪切速率曲线表明蛋白质交联程度较高的体系黏度增加明显,频率扫描结果进一步证实蛋白质质量分数较高的体系凝胶网络结构的形成;质构仪测试了此凝胶体系的强度,证实混合体系凝胶比单一ADRP的蛋白凝胶具有更高的破裂强度。ADRP和葡聚糖的相分离是混合体系中蛋白质网络结构形成的可能原因。     

纸浆纤维表面特性与表面化学成分的研究方法和研究进展

该文以表面分析技术为出发点,阐述了纸浆纤维表面性能的重要性,并通过介绍主要的表面分析技术,如原子力显微镜(AFM)、激光共聚焦扫描显微镜(CLSM)、二次离子质谱(SIMS)等现代表面分析技术及其在制浆造纸领域中的应用,综合论述了纸浆纤维的表面特性和表面化学成分的研究方法和研究进展。