环糊精的性能,生产及其在食品中的应用

环糊精由６－１２个葡萄糖单位连接而成，分子呈环状结构，形如空心圆筒，其它物质可装填其中而形成包络物，产生许多新的功能，由此而在食品、医药、化工等行业得到广泛应用。环糊精的生产主要用酶法降解淀粉再分离精制而得。本文介绍了环糊精的结构、性能、生产方法及应用研究发展等情况。     

环糊精的性能、生产及其在食品工业中的应用

本文介绍了环糊精的结构、性能、生产方法及其在食品工业中的应用等。     

β—环糊精的性质及其利用

β—环糊精是环糊精(Cyclodcxtrin,简称CD)的一种。环糊精是由6—12个葡萄糖单元以2—1.4糖甙键连结而成的一族低聚糖化合物。由于它们的环状空筒形结构能包合其它一些物质,因此成了引人注目的一种新型包合材料。目前生产应用最多的是β—环糊精(β—CD)。     

环糊精及其衍生物在废纸造纸湿部中的应用现状及展望

环糊精是由不同的β-吡喃葡萄糖单元环状排列而成的圆锥状中空桶形分子,其独特的外亲水、内疏水结构决定了其特殊的性能。目前环糊精及其衍生物在医药、水处理方面应用广泛,但在造纸湿部中的应用很少。该文主要介绍了环糊精的结构、环糊精衍生物和环糊精聚合物的合成方法及其种类;综述了环糊精衍生物在废纸造纸湿部中的应用现状,预测了其在阴离子垃圾捕捉剂和助留助滤剂中的广阔应用前景。     

基于β-环糊精稳定的Pickering乳液微观结构与流变性质研究

以食用大豆油为油相,采用高速均质方式制备了β-环糊精稳定的水包油型Pickering乳液,考察了环糊精质量浓度、油水体积比等对乳液微观结构与流变性质的影响,并与非离子表面活性剂吐温-80稳定的乳液进行粘度及稳定性比较。实验结果表明:随着β-环糊精质量浓度的增加,乳液乳化系数增大,粒径减小;β-环糊精乳液粒径显著小于吐温-80乳液;β-环糊精乳液的粘度显著高于吐温-80乳液的粘度,β-环糊精乳液粘度随剪切速率的增加而降低,而吐温-80乳液粘度随剪切速率的增加而增加;随着油水体积比增加,β-环糊精乳液乳化系数增大,粒径增大。     

环糊精的选择性化学修饰及其应用

外形似"锥筒",腔内疏水、腔外亲水的环糊精(Cyclodextrin,CD)包括α、β、γ等,以其特有的结构在模拟酶、分子识别,以及食品、日用品、医药、化学工业和农业等众多领域深受广大科学工作者的重视.β-环糊精分子本身作为主体模型在具体应用中还有一定的局限性,为了获得更好的β-环糊精功能主体模型,对β-环糊精进行适当的选择性化学修饰是很有必要的.本文综述了环糊精的结构、性能及环糊精的改性方法和改性后环糊精的应用.     

β-环糊精及其衍生物增加客体分子水溶性的研究进展

β-环糊精及其衍生物对不同结构的客体分子的包合稳定性会因包合介质、包合温度、客体分子大小及氢键的形成等诸多因素的影响而产生较大差异,而环糊精包合物的形成不仅对疏水性客体分子的溶解度、生物利用度、安全性和稳定性有显著影响,还在减小疏水性客体分子刺激性、去除和掩盖其不良气味以及控制其释放速率等方面发挥重要作用。本文对常见β-环糊精衍生物的特点进行了归纳,并重点讨论了黄酮类化合物、多酚类化合物、香豆素类化合物和萜类化合物等客体分子与β-环糊精及其衍生物形成稳定包合物时包合方式的差异以及β-环糊精及其衍生物在增溶方面的应用,为β-环糊精及其衍生物在食品相关领域对不同疏水性功效成分增溶作用的探究提供理论参考。     

β-环糊精的选择性化学修饰

最近20多年来，外形似“锥筒”，腔内疏水、腔外亲水的环糊精（Cyclodextrin，CD）包括α、β、γ等，以其特有的结构在模拟酶、分子识别，以及食品、日用品、医药、化学工业和农业等众多领域深受广大科学工作者的重视。β-环糊精分子本身作为主体模型在具体应用中还有一定的局限性，为了获得更好的β-环糊精功能主体模型，对β-环糊精进行适当的选择性化学修饰是很有必要的。本文综述了环糊精的结构、性能及环糊精的改性方法和改性后环糊精的应用。     

德国瓦克公司开拓食品配料新领域

<正>今年在FIC展会上,德国瓦克公司向中国市场推出了一系列高性能的食品配料:即α-环糊精、β-环糊精和γ-环糊精。据公司高级工程师张忠慧女士介绍,环糊精是瓦克利用生物技术通过酶解玉米、土豆等植物原料生产而来,它具有独特的环状结构,其中间的桶状空腔可包合其他一些具有疏水性的物质,起到稳定敏感成分、提高功能性成分的生物利用率、掩盖异味的作用。德国瓦克公司是一家全球著名化学品公司,旗下拥有世创电子材料、瓦克有机硅、瓦克聚合物、瓦克多晶硅和瓦     

羟丙基环糊精性质、应用及前景展望

该文主要介绍羟丙基环糊精,特别是羟丙基-β-环糊精制备方法、结构、功能和毒理学特性,羟丙基环糊精与客体分子复合物形成和客体分子释放,及目前羟丙基环糊精在食品、医药、农业等领域应用,并对其应用前景进行展望。     

Structural and physical properties of dietary fibres,and consequences of processing on human physiology

Dietary fibre encompasses very diverse macromolecules exhibiting a large variety of physico-chemical properties. They might be naturally present in the food (in cell walls of vegetables and fruits, for instance) or introduced in the food to improve their nutritional properties (e.g. bran in bread products) or their physical characteristics (e.g. gelling agents or improved resistance to storage). The properties that are nutritionally relevant are mainly the particle size and bulk volume, the surface area characteristics, the hydration and rheological properties, and the adsorption or entrapment of minerals and organic molecules. Amongst these properties, the viscosity and ion exchange capacity are the main contributors to metabolic effects (glucose and lipid metabolisms) whereas fermentation pattern, bulking effect and particle size are strongly involved in effects on colonic function. Technological treatments can modify the physico-chemical properties of the fibre. This can be further exploited to optimise both their techno-functional and physiological properties.     

Use of Water Properties in Food Technology: A Global View

Water is a major component of drinking water, beverages, and most foodstuffs. In this study, an effort has been made to employ selected properties of water for: (1) evaluation of interactions of water with other food components; (2) discussion on the effects of water properties on food and beverage products; (3) applications of water properties in food technology; and (4) comparison of water properties with corresponding properties of similar substances. This study provides the following major conclusions: (i) unusual properties of water are mostly due to its high permanent dipole moment, partial ionic character of O–H covalent bonds, and extensive hydrogen bonds; (ii) different properties of many foodstuffs are strongly related to various properties of water; (iii) the properties of food products change depending on water availability and temperature; (iv) preparation of drinking water is a prerequisite for production of any safe drinks and foodstuffs; (v) water contributes important roles in quality, flavor, and shelf-life of foods; and (vi) water is used in food industries as a fluid for heat transfer; as a medium for temperature moderation in food processing; as a solvent for sugars, salts, water-soluble vitamins, and acids; as a dispersing agent for hydrophilic food components; as a dispersed phase for emulsified products; or as a reactant for several reactions in food processing.     

Non-linear Theory of the Biaxial Deformation of a Triaxial-weave Fabric

A new theory predicting the biaxial tensile properties of a triaxial-weave fabric is presented. This theory is based on the plain-weave theory developed by Kawabata, Niwa, and Kawai in 1973 and improved by Kawabata in 1984. The basic structures of the fabric are (i) the thread-spacing of two warp threads and one weft thread, (ii) the weave-crimp shrinkage of the three threads, and (iii) the crossing angles between these threads. The yarn properties applied in this theory are the tensile properties, the lateral-compressional properties, the bending property, and the yarn-crossing-torque property. The biaxial tensile properties of the triaxial-weave fabric are then derived by solving an equilibrium equation of the forces acting at a thread-crossover point. The prediction and the experimental result coincide well over the wide range of deformation from the small-strain region to the finite-deformation region near breaking strain. The theoretical analysis shows that the yarn lateral-compressional properties have a significant effect upon the fabric tensile properties, and the effects of the yarn-bending and crossing-torque properties are negligibly small except for the very small-strain region. It is also shown that the tensile properties of the triaxial-weave fabric are much more isotropic than those of the ordinary woven fabric because of the symmetrical structure which appears for every 30° angle rotation of the fabric in the plane of the fabric, and it is demonstrated that the tensile properties of the triaxial-weave fabric are, in fact, almost completely isotropic.     

Recent advances in phosphorylation of food proteins: A review

Phosphorylation is a useful method for improving the functional properties of food proteins. In this article, various methods of phosphorylation are reviewed. Dry-heating phosphorylation, a method developed recently, is also introduced. Some characteristics of phosphate groups are involved, and the effects of phosphorylation on the structural changes, the functional properties, and the physiological functions in vitro of food proteins, are discussed. The types of phosphate linkages and the phosphopeptides from phosphorylated proteins are identified. The molten (partially unfolded) conformations of food proteins formed by phosphorylation are discussed. The phosphorylation of food proteins improved a number of functional properties, including heat stability, emulsifying properties, foaming properties, gelling properties, water absorption capacity, oil absorption capacity, and calcium phosphate-solubilizing ability. In vitro physiological function studies of protein (α-lactoalbumin) indicated that the digestibility (ovalbumin) was improved and the inflammatory response (α-lactoalbumin) was suppressed by phosphorylation. Experiments with animals are necessary to evaluate the toxicity and physiological functions of phosphorylated proteins.     

无元素氯漂白浆的性质

氧脱木素的硫酸盐浆,采用 ECF无元素氯漂白,以 DEoD1ED2流程漂白浆为参比,对比了(DZ)EoD1ED2、DEoQ(PO)和(DZ)EoQ(PO)漂白浆的强度及其漂白废水污染的特性.     

壳聚糖改性水性聚氨酯的性能

以聚酯218、聚四氢呋喃醚二醇(PTMEG-2000)和异佛尔酮二异氰酸酯(IPDI)为主要原料,2,2-二羟甲基丁酸(DMBA)为亲水扩链剂,柠檬酸化壳聚糖(CA-CS)为改性剂,合成了壳聚糖改性水性聚氨酯抗菌整理剂(CA-CS-WPU).采用傅里叶变换红外光谱、热重分析、差示扫描量热法对乳液及胶膜的各项性能进行表征...     

不同结构厚截面三维机织碳纤维复合材料的弯曲性能对比

为准确分析不同结构厚截面复合材料不同方向上的弯曲性能差异,通过设计织造三向正交、浅交直联、浅交弯联3种典型机织结构的厚截面碳纤维三维机织物,并采用真空辅助树脂成型工艺制备了近似纤维体积含量的碳纤维复合材料板,对其进行了XYZ方向的弯曲实验。结果表明:三向正交结构由于内部纤维束近似平直,碳纤维束自身性能得到最大利用,对应复合材料经向弯曲强度最好;浅交直联结构复合材料的Z经和Z纬弯曲强度累加值最大,其厚度截面上的综合弯曲性能最好,且其他各方向的弯曲强度较为均衡;浅交弯联结构内部纱线交织摩擦损伤严重,且经纱屈曲程度最大,对应复合材料经纬向弯曲性能均为最差。     

THERMAL AND RHEOLOGICAL PROPERTIES OF BRINE FROM FERMENTED AND SULFITE‐PRESERVED CUCUMBERS1

Pickling cucumbers may be temporarily preserved by fermentation in brine (6–8% NaCl) or without fermentation in salt‐free, sulfite solution (300 ppm sulfite, pH 3.5). Brines obtained from preservation processes are often discarded. Due to environmental concerns, there is increasing consideration for further use of the brine solutions by recycling for use in bulk storage or filtration and incorporation into finished products. Thermal and rheological properties are fundamental to the reuse of the brine. The effect of temperature was determined on the rheological (5–45C) and thermal properties (5–75C) of brine. The properties of the brine samples were found to be significantly different (P < 0.05) from each other and from water. Salt content was the most important factor affecting the thermal and rheological properties of brine. At the same conditions, the values of the properties (thermal conductivity, specific heat, and thermal diffusivity, viscosity) were about 5 to 23% less than the corresponding values for water.     

碱性H2O2漂白及其对高得率浆性能的影响

高得率浆(HYP)的生产过程中采用碱性H2O2漂白工艺.漂白工段是控制HYP浆性能,使其满足特定纸种对纸浆的质量要求的关键工艺过程.在碱性H2O2漂白过程中,纤维素、木素、半纤维素、果胶、抽出物及其他木材成分发生一系列化学和物理变化.本文对这些变化及草酸钙引起的结垢和阴离子垃圾的产生等问题做了概括性总结.除了白度提高之外,碱性H2O2漂白可以大大提高HYP浆的抗张强度,但同时也在一定程度上降低其光散射系数和松厚度,这3个性能指标互相关联.本文也总结性地讨论漂白对HYP浆性能的影响.     

相思木浆用于文化用纸生产时的滤水性能和留着性能

对来自印度尼西亚的相思木 (Acacia)浆与混合阔叶木浆和来自北欧的桦木浆进行对比分析 ,以期获得用于文化用纸生产时湿部的潜在滤水、留着性能及相关的手抄片性能 ,这些性能比较均基于恒定的抗张强度水平。相思木浆被证明拥有在文化用纸生产中至关重要的光散射能力、湿部成形和填料留着能力方面的优越性。需要改进的地方是 :它的滤水速率和湿纸幅强度较低 ,这些将是现代高速纸机湿部的瓶颈所在。相比之下 ,桦木浆具有较快的滤水速率和较高的湿部固含量 ,但其留着性能还有待改进