酶催化魔芋葡甘聚糖的可控降解

魔芋葡甘聚糖 (KGM)是一种来自植物的天然高分子 .它具有优异的可生物降解性和生物相容性 ,并具有许多独特的生理和药理功能 .本实验首先测定了 β 甘露糖酶在不同条件 (温度、pH值、介质 )下的活性 ,发现 β 甘露糖酶在 5 0℃左右 ,pH 9 4附近 ,乙醇含量低于 5 %的水介质中具有较高的活力 ;而在pH 7 0以下 ,或温度低于 3 0℃ ,或加入 2 0 %乙醇的条件下均基本上失活 .在此研究基础上 ,探讨了 β 甘露糖酶催化KGM降解反应的规律 ,通过调节反应条件制备了一系列分子量不同的降解样品 ,并确定了KGM的分子量与特性粘数之间的关系为 :[η]=5 0 6× 1 0 - 4M0 754w ,使得酶催化KGM的可控降解成为可能 ,从而为深入研究KGM及其衍生物的结构与性能 ,扩展其应用领域奠定了良好的理论和实验基础     

Molecular Dynamics Simulation of Glucomannan Solution

1 INTRODUCTION Konjac Glucomanan (KGM), found in konjac plant with molecular weight ranging from 2×105 to 2×106[1], is neutral polyoses with excellent water solubility. The structural studies of KGM have been well presented, but its accurate structure has not been clearly clarified so far, so the investigation is still in progress. According to the previous studies[2～4], the conjectural structure of KGM is as follows: KGM is natural polyoses formed by D-glucose and D-mannose link…     

红枣汁与魔芋凝胶复合果冻的研制

采用正交优化方法,以红枣汁与魔芋精粉为主要原料研制红枣汁复合果冻.对红枣汁、魔芋精粉、κ-卡拉胶混合胶等的用量、氯化钾添加量、蔗糖与柠檬酸添加比例等工艺条件进行了研究,得到了红枣汁魔芋凝胶复合果冻的最佳工艺配方:红枣汁8.00%、魔芋精粉0.28%、κ-卡拉胶0.42%、氯化钾0.60%、白沙糖5.00%、柠檬酸0.10%.该配方制作的果冻呈橘黄色,香味浓郁,爽滑可口.     

交联羧甲基魔芋葡甘聚糖空心微球制备及应用

以魔芋葡甘聚糖(KGM)为壁材,通过羧甲基化并经乳状液化学交联制备球体较为完好的羧甲基魔芋葡甘聚糖(CMKGM)空心微球.通过扫描电镜(SEM)和透射电镜(TEM)对CMKGM空心微球的形貌和粒径进行了表征.结果表明,KGM溶胶浓度为0.5%-1%、乳化剪切速率为8000r/min、环氧氯丙烷(ECH)为5ml时,可以得到粒径均匀、形貌规整、溶胀性能良好的CMKGM空心微球.增大溶液的pH和羧甲基试剂的用量均有利于CMKGM空心微球对水中Cu2+的吸附.     

Structure of Narcissus tazetta Glucomannan

Naturally acetylated glucomannan with MW 31,000 and []_D ²⁰ -29.1° was isolated from bulbs of Narcissus tazetta L. Chemical methods and IR and ¹³C NMR spectroscopies were used to show that the polysaccharide contains 12.9% O-Ac groups and consists of D-mannose and D-glucose in a 1:5.6 ratio that form a linear polymer through -1,4-glycoside bonds.     

Water-Soluble Polysaccharides from Narcissus poeticus and Their Biological Activity

A homogeneous native acetylated glucomannan of molecular weight 32000 was isolated from bulbs of N. poeticus. A linear chain polymer consisting of -14-bound D-manno- and D-glucopyranoses was found using periodate and chromic oxidation and methylation. The glucomannan has low toxicity and exhibits distinct hypolipidemic activity.     

Hydrogel Emulsion with Encapsulated Safflower Oil Enriched with Açai Extract as a Novel Fat Substitute in Beef Burgers Subjected to Storage in Cold Conditions

This study evaluates the effects of using a fat substitute in beef burgers composed of a hydrogel emulsion enriched with encapsulated safflower oil and açai extract. The influences of the fat substitute on the chemical (TBARS, fatty acids, and volatile compounds profile) and physical (weight loss, cooking loss, water-holding capacity, color, and texture analyses) characteristics of the burgers were analyzed after 0, 4 and 8 days of storage at 4 ± 1 °C. The obtained results were compared with control groups (20 g of tallow or 8 g of safflower oil). The fat substitute used improved burger parameters such as chewiness, hardness and the a* color parameter remained unchanged over storage time. The addition of açai extract slowed the oxidation rate of polyunsaturated fatty acids and reduced the changes in the volatile compounds profile during the storage of burgers. The utilization of a fat substitute enriched the burgers with polyunsaturated fatty acids and lowered the atherogenic index (0.49 raw, 0.58 grilled burger) and the thrombogenicity index (0.8 raw, 1.09 grilled burger), while it increased the hypocholesterolemic/hypercholesterolemic ratio (2.59 raw, 2.09 grilled burger) of consumed meat. Thus, the application of the presented fat substitute in the form of a hydrogel enriched with açai berry extract extended the shelf life of the final product and contributed to the creation of a healthier meat product that met the nutritional recommendations.     

Studies on the Effect of Structure to Property Stability of Glucomannan

1 INTRODUCTION Directive action of hydrogen bond paves the way for new fields of biological activity, molecular re- cognition and crystal engineering[1]. Hydrogen bond plays an important role in the physical and chemical properties, such as melting point, boiling point, solu- bility, acid strength, viscosity and hardness degree[2]. At present, the popular tools used to investigate hy- drogen bond include wet melting point method, chromatography analysis method, spectrum method and diffract…     

分子量及酰基供体对酶促魔芋葡甘聚糖酰化反应的影响

研究了在有机介质叔丁醇中魔芋葡甘聚糖(KGM)的分子量及酰基供体对固定化脂肪酶Novozym 435催化KGM乙酰化反应的影响.KGM的分子量对酶促其酰化反应的活性及产物取代度有显著影响.随着KGM分子量的增大,酶催化反应的速率逐渐下降,产物的取代度逐渐减小.KGM分子量对该反应的影响与不同分子量KGM的溶解度、体系粘度、空间位阻及颗粒形态等因素有关.以不同链长的脂肪酸乙烯酯为酰基供体时,随着酰基供体中脂肪酸碳链的增长,酶促KGM酰化反应速率逐渐下降,产物的取代度逐渐减小,且该酰化反应具有高度的区域选择性,反应均发生在C6-OH上.     

The Effect of Boron on the Properties of Glucomannan： An Experimental and Molecular Dynamics Simulation Study

1 INTRODUCTION gel using KGM and borax at 60 ℃, which can be used as slow-released reagent of theophylline and Generally, the mixture of Konjac Glucomanan dibucaine. And Hogi Tsuneo utilized KGM and tetra- (KGM) and salts that could be hydrolyzed to form valent boric acid to prepare artificial crystal[1]. This multi-hydroxyl hydrates leads to the generation of kind of crystal has good light transmission property, gelatum. Among the familiar salts, such as borate, elasticity, intensi…