新奇环状淀粉——大环糊精的最新研究进展

大环糊精是一类由9个以上葡萄糖基组成的环状糊精混合物总称,由于其特异的分子结构和性质,具有广泛的工业应用前景,最近10年在国际上引起了广泛的关注和研究。分析了在大环糊精的合成、分离纯化及其结构和应用等方面的最新研究进展,指出了存在的问题和下一步的研究方向,并分析了其潜在的工业应用前景。     

生淀粉生产环糊精的研究

介绍了以马铃薯生淀粉生产环糊精的方法。对生淀粉生产过程中的马铃薯、玉米、木薯生淀粉转化做了比较 ,并对反应条件对转化的影响做了研究。     

天然胡萝卜素β-环糊精微胶囊制备工艺的研究

对胡萝卜素β-环糊精微胶囊制备工艺进行了研究,结果表明:最佳工艺条件是胡萝卜素油(mL)与β-环糊精(g)比值为1∶8,加水量80mL,搅拌时间5h,搅拌温度50℃,搅拌速度1200r/min。显微镜成像法和红外光谱法验证了胡萝卜素包埋物的形成。     

无机溶剂法制β-环糊精的工艺研究

对一种无机溶剂酶催化生产β-环糊精的工艺进行研究,并采用响应面实验法确定了生产β-环糊精的适宜工艺条件,为其开发研究应用提供参考。实验结果表明,生产争环糊精的最佳条件是选取木薯淀粉作为底物,不经过预处理,环状糊精葡萄糖基转移酶添加量是4u/g,CaCl2的浓度为30mmol/L,pH7．88,温度63．67℃,反应时间17．24h,产率可达24．02％。生产工艺和传统工艺相比,产率明显增高,提高了生产效率。     

应用环糊精控制胶黏物

环糊精是由6～8个葡萄糖单元组成的环状结构。实验室研究表明,它可以有效降低胶黏物的黏性以及抑制微胶黏物的絮聚和沉积。接触角实验表明,环糊精可提高压敏胶薄膜的亲水性,增强可湿性。环糊精在一定程度上还可以降低树脂类物质的黏性。在新闻纸厂的2次试验表明,β-环糊精可以降低滤液的黏性,且在β-环糊精低用量下就能起到很好的作用（增加其用量反而会起到相反的效果）。     

利用环糊精控制胶粘物的研究

环糊精是由6～8个葡萄糖单元组成的环状结构。实验室研究表明,它可以有效降低胶粘物的黏性并抑制微胶粘物的絮聚和沉积。接触角的测量表明,环糊精可提高压敏胶薄膜的亲水性,增强可湿性。环糊精在一定程度上还可以降低树脂类物质的黏性。在新闻纸厂的2次试验表明,β-环糊精可以降低滤液的黏性,且在β-环糊精低用量下就能起到很好的作用（用量增加反而会起到相反的效果）。     

环糊精在食品业等方面的应用

本文介绍环糊精的特性、制备和使用方法以及它在食品业等领域的应用。     

中等聚合度大环糊精的包埋能力初探

目前关于大环糊精包埋能力的研究较少。研究利用耐热性糖基转移酶制备聚合度在23~27的大环糊精,利用静态顶空气相色谱法研究大环糊精与风味成分的包埋作用,利用相溶解度法研究大环糊精与染料木苷的包埋作用,并与小环糊精的包埋能力进行了比较。结果表明,对于所选客体,中等聚合度大环糊精的包埋能力不如α-CD、β-CD和γ-环糊精。其中,大环糊精对风味庚酮、辛酮和癸酮的包埋能力很弱,对丁酸乙酯、己酸乙酯、辛酸乙酯和柠檬醛的包埋能力有所提高,对染料木苷的包埋能力相对较强。     

响应面分析法优化β-环糊精的制备工艺

该文对β-环糊精制备工艺用响应面分析法优化进行了研究。结果表明,生产β-环糊精的最佳条件是选取木薯淀粉作为底物,不经过预处理,环状糊精葡萄糖基转移酶添加量是7U/g,环己烷的添加量0.5mL/g,体系CaCl2的浓度是50mmol/L,pH值8.25,温度63.72℃,反应时间9.04h,产率可达51.98%。优化后的生产工艺和传统工艺相比,反应时间缩短了5h,并且产率增高了1.13倍。     

大环糊精包埋制霉菌素的研究

大环糊精（LR-CD）具有优于普通环糊精（α-环糊精、β-环糊精、γ-环糊精）的高水溶性、低粘度、不回生等特性,但目前关于大环糊精的应用研究非常少。本文以共轭四烯类大环内酯抗生素制霉菌素为客体,探讨了大环糊精对制霉菌素的包埋能力,结果表明,LR-CD的相溶解曲线为AL型,计算得到LR-CD包埋制霉菌素的包合常数为1.577L/mmol,远远大于β-环糊精和γ-环糊精对制霉菌素的包埋常数（0.375L/mmol和0.539L/mmol）;预测饱和环糊精溶液对制霉菌素的增溶倍数为2958.87倍;红外光谱鉴定表明制霉菌素的酯键及二烯部分进入到环糊精的空腔,而共轭四烯部分及羧基、氨基部分在环糊精腔体表面。      

Study on Specific Modification of Glucosyl Cyclodextrins

The time courses of the periodate oxidation of glucosyl cyclodextrins complexed with organic solvents indicated the preferential oxidation of glucosyl residues on side chains, and the modified cyclodextrins could be purified by using a reversed phase column. HPLC and ¹³C-NMR analyses ensured that the modified cyclodextrins were cyclodextrins having aldehyde residues on their side chains (aldehyde cyclodextrins).     

Cyclodextrins: Production,properties and applications in food chemistry

Cyclodextrins have diverse, important applications in food industry. These applications are based on the ability of cyclodextrins to form molecular complexes with small—molecular compounds. Cyclodextrins are harmless in oral administration and advantageous effects by cyclodextrins are achieved by simple mixing of small amounts of them to the material being stabilized. Development of convenient and cost‐effective processes for production of cyclodextrins are undergoing and there are promises in the near future for obtaining cyclodextrins which are realistic in price to be used in foods. While cyclodextrins have been used for more than ten years in Japan as natural additives in foods, the legislation for their approval in foods is still under development in Europe and USA.     

环糊精超分子自组装包合机制研究进展

环糊精因具有独特的“外亲水、内疏水”结构,可作为一种优良的包合载体对性质活泼、易挥发、易氧化分解的活性组分进行保护,从而达到提高其溶解度、稳定性和生物利用率的效果。本文从环糊精的结构与性质出发,首先对其包合机理进行探究,即分析主体环糊精与客体分子之间的相互作用和影响因素,包括环糊精单体与客体之间的包合反应、环糊精单体之间的自组装行为以及该行为下所形成的超分子体系与客体分子的包合机制;接着阐述有无表面活性剂存在的情况下环糊精界面稳定机制、表面活性剂与环糊精自组装形成复合乳化剂协同稳定客体机制等;然后,对环糊精包合物中客体分子的释放机制、缓释动力学模型及相应的影响因素进行解析;最后,从分子模拟及界面稳定机制方面对环糊精在超分子领域的研究进行展望,以期为后续研究提供参考。     

环糊精包合碘的制备、表征及其应用研究进展

环糊精包合碘由于特殊的包合碘的方式,在医药,食品和农业方面具有广阔的应用前景。本文系统地介绍了环糊精包合碘的制备、表征和应用方面的研究进展,为今后环糊精包合碘的深入研究提供理论支持。      

Cyclodextrins and Antioxidants

In recent years, the growth of the functional foods industry has increased research into new compounds with high added value for use in the fortification of traditional products. One of the most promising functional food groups is those enriched in antioxidant compounds of a lipophilic nature. In spite of the numerous advantages reported for such antioxidant molecules, they may also have disadvantages that impede their use in functional foods, although these problems may well avoided by the use of encapsulant agents such as cyclodextrins. This explains the recent increase in the number of research papers dealing with the complexation of different guest molecules possesing important antioxidant properties using natural and modified cyclodextrins. This paper presents a review of the most recent studies on the complexes formed between several important types of antioxidant compounds and cyclodextrins, focusing on the contradictory data reported in the literature concerning to the antioxidant activity of the host/guest molecule complexes, the different complexation constants reported for identical complexes, the bioavailability of the antioxidant compound in the presence of cyclodextrins and recommendation concerning the use of natural or modified cyclodextrins. Moreover, the use of cyclodextrins as antibrowning agents to prevent enzymatic browning in different foods is revised. Finally, we look at studies which suggest that cyclodextrins act as ‘‘secondary antioxidants,” enhancing the ability of traditional antioxidants to prevent enzymatic browning.     

改性环糊精及其应用

该文主要介绍环糊精改性意义,改性环糊精分类,改性方法及主要改性衍生物,并介绍改性环糊精在食品、医药、农业等领域应用前景。     

A Polarographic Cyclodextrin Assay Based on Linoleate-Cyclodextrin Complex Formation in a Lipoxygenase Reaction

A polarographic assay of cyclodextrins in turbid dextrin mixtures is described. The method is based on the ability of cyclodextrins to form complexes with linoleic acid and on the inability of soybean lipoxygenase to oxidize the complexed acid. The degree of complexation is measured with a simple Clark's electrode as a reduced rate of oxygenation of linoleate. Cyclodextrin concentrations down to 0.02–0.04-mM can be assayed. The method is rapid to carry out because several successive samples can be added into a single lipoxygenase assay mixture. The method was applied to analyses of immobilized cyclodextrins as well as cyclodextrins in complex mixtures of starch and starch degrading enzymes. The conditions for spectrophotometric measurement of the reaction are also described.     

Interference of Cyclodextrins with Amylolytic Activity Assays of Cyclodextrin Glycosyltransferases

Cyclodextrin glycosyltransferases (CGTases) catalyse the cyclisation of starch dextrins to cyclodextrins and concomitantly show amylolytic activity which is commonly determined by the starch-iodine assay. In the present study it was found that cyclodextrins interfere with this assay. Adding cyclodextrins in concentrations ranging from 0.01mM to 0.6mM to starch-iodine complex solution resulted in a significant decrease in absorbance at 600nm due to α- and β-cyclodextrin competing with starch in the iodine complex formation. The largest reduction was caused by α-cyclodextrin. Therefore, the use of the starch-iodine assay will result in an overestimation of the amylolytic activity of CGTases – particularly when the enzyme has a high α-cyclodextrin production activity. In contrast, determination of the amylolytic activity by measurement of released reducing sugars with CuSO₄/bicinchonate was not disturbed by cyclodextrins.     

Cyclodextrins: a new group of industrial basic materials

Adequate toxicological studies, discovery of numerous potential fields of utilization and last but not least, the production of cyclodextrins on industrial scale with high homogeneity and low price led to their recognition as a new group of industrial basic materials. Until now cyclodextrins were considered merely as agents for molecular encapsulation, however intensive research of the past few years revealed quite new and unexpected aspects: cyclodextrins, their derivatives and polymers can be applied--not exclusively due to their complexing ability--in foods, cosmetics, pharmaceuticals, chromatography, pesticide formulations, in photochemistry, etc.     

Cyclodextrin Degrading Enzymes

Cyclodextrinase is an enzyme that hydrolyzes cyclodextrins. Some amylolytic enzymes can also hydrolyze cyclodextrins. A comprehensive review of these cyclodextrin degrading enzymes and their action pattern is presented.