微生物多糖在农业上的应用

三种由微生物发酵生产的多糖，短梗霉多糖（ｐｕｌｌｕｌａｎ）、小核菌多糖（ｓｃｌｅ－ｒｏｇｌｕｃａｎ）和黄原胶（Ｘａｎｔｈａｎｇｕｍ）由于其独特的物理、化学性质在农业上具有应用潜力。短梗霉多糖可形成透气性能低的膜和具有良好可塑性，可用于农产品保鲜、颗粒肥料和农药成型；小核菌多糖和黄原胶具有优良悬浮性能，可用于流动杀虫剂、液体饲料；小核菌多糖能与多种盐类配伍，可用于悬浮液体肥料。     

瓜尔胶对浆膜性能和粘附力影响的探讨

介绍了瓜尔胶的性能,对添加瓜尔胶以降低淀粉混合浆中PVA的用量进行了浆膜性能和浆液粘附力试验.结果表明,瓜尔胶的加入能提高变性淀粉的用量,有效改善混合浆的成膜性和粘附性.     

黄原胶溶液减阻特性实验

采用较粗水平圆管对两种温度多种浓度黄原胶溶液进行了较系统的实验研究,并应用Metzner-Reed广义雷诺数定义,对管道中不同流动状态的广义雷诺数进行了计算,得到了Fanning系数和广义雷诺数关系图,发现黄原胶溶液从层流到紊流转捩点的广义雷诺数随着溶液浓度的升高而增大,给出了转捩点广义雷诺数与溶液浓度变化的关系表达式.此外还发现:在层流区,黄原胶溶液的Fanning阻力系数与广义雷诺数之间具有良好的线性关系,与牛顿流体阻力系数图吻合,这与前人的理论分析及实验研究结果一致;在紊流区,黄原胶溶液具有明显的减阻效应,减阻效应随着溶液浓度的升高而增大.     

中药杜仲炮制的现代研究进展

目的对杜仲现代炮制的研究进展作一综述。方法通过文献研究,详细分析杜仲炮制火候、辅料及单一成分与药理作用在炮制前后的变化,全面了解杜仲现代炮制研究进展。结果杜仲炮制以盐炙法为主流方法,但炮制方法及条件尚需进一步深入全面的考察。结论建议综合分析杜仲数种活性成分与药理作用在炮制前后的变化,考察影响杜仲炮制效果的主要因素。     

杜仲叶中抗氧化活性成分的提取

以体外总抗氧化能力为活性跟踪指标,采用单因素试验研究了超声波提取杜仲叶中抗氧化物活性物质的提取条件。结果表明,杜仲叶中总抗氧化物质的最佳提取条件为:以20%乙醇水溶液为提取剂,料液比为1:18,提取40 min,提取2次。     

A study of the effect of locust bean gum on the rheological behaviour and microstructure of a β-lactoglobulin gel at pH 7

The effect of locust bean gum (LBG), a non-gelling polysaccharide, on the thermal gelation of -lactoglobulin, at 80 °C, and on the gel properties after quenching to 20 °C was studied by small deformation rheology and by confocal laser scanning microscopy (CLSM). The concentration of -lactoglobulin was kept constant at 10 wt% and that of LBG varied from 0 to 0.78 wt%. For all the concentrations studied, the presence of LBG enhanced the aggregation rate and the strength of the protein gel, but the magnitude of these effects depended on the -lactoglobulin/LBG ratio: 0.35 wt% LBG resulted only in a very slight increase of G, whereas 0.45 wt% LBG caused a ~fivefold jump; for higher LBG concentrations, the differences between the systems were quite small. The linear viscoelastic behaviour, at 20 °C, was characterized over the 10^–5 to 100 rad/s frequency range by combining the dynamic and retardation tests. Compliance data were converted from the time to the frequency domain. The viscoelastic plateau was seen to extend down in the 0.001–0.0001 rad/s range and its lower limit seemed not to vary much with LBG concentration. Its upper limit was visibly beyond 100 rad/s. The observed microstructure of the gels showed that they were two-phase and that the state of aggregation of -lactoglobulin was influenced by the -lactoglobulin/LBG ratio.This paper was presented at the first Annual European Rheology Conference (AERC) held in Guimarães, Portugal on September 11–13, 2003     

Tragacanth gum‐based pH‐responsive magnetic hydrogels for “smart” chemo/hyperthermia therapy of solid tumors

The drug delivery performances of pH‐responsive magnetic hydrogels (MHs) composed of tragacanth gum (TG), poly(acrylic acid) (PAA), and Fe₃O₄ nanoparticles (NPs) were investigated in terms of physicochemical as well as biological features. The fabricated drug delivery systems (DDSs) were analyzed using Fourier transform infrared spectroscopy, X‐ray diffraction, vibrating sample magnetometer, scanning electron microscopy, and transmission electron microscopy. The synthesized MHs were loaded with doxorubicin hydrochloride (Dox) as a universal model anti‐cancer drug. The MHs showed excellent Dox loading and encapsulation efficiencies, mainly due to strong hydrogen bonding and electrostatic interaction between the drug and polymeric matrix, as well as porous micro‐structures of the fabricated MHs. The drug‐loaded MHs showed negligible drug release values in physiological condition. In contrast, in cancerous condition (pH 5.0), both MHs exhibited highest drug release values that qualified them as “smart” DDSs. The cytocompatibilities of the MHs as well as the cytotoxicity of the Dox‐loaded MHs were investigated against human epidermoid‐like carcinoma (Hela) cells through MTT assay. In addition, hyperthermia therapy induced by Fe₃O₄ NPs was applied to locally raise temperature inside the Hela cells at 45 ± 3°C to promote cell death. As a result, the Dox‐loaded MHs can be considered as potential DDSs for chemo/hyperthermia therapy of solid tumors.     

Effect of Cryostructuring Treatment on Some Properties of Xanthan and Karaya Cryogels for Food Applications

Cryogels are novel materials because the manufacturing process known as cryostructuring allows biopolymers to change their properties as a result of repeated controlled freeze–thaw cycles. Hydrogels of xanthan and karaya gums were evaluated after undergoing up to four controlled freeze–thaw cycles in indirect contact with liquid nitrogen (up to −150 °C) to form cryogels. Changes in structural, molecular, rheological, and thermal properties were evaluated and compared to those of their respective hydrogels. Samples were also analyzed by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), Rotational Rheology (RR), Modulated Differential Scanning Calorimetry (MDSC) and zeta potential (ζ). In general, significant differences (p < 0.05) between the numbers of freeze–thaw cycles were found. Karaya cryogels were not stable to repeated cycles of cryostructuring such as the three-cycle xanthan cryogel, which has the best structural order (95.55%), molecular interactions, and thermal stability, which allows the generation of a novel material with improved thermal and structural properties that can be used as an alternative in food preservation.     

Effect of dry heat modification and the addition of Chinese quince seed gum on the physicochemical properties and structure of tigernut tuber starch

To expand industrial utilization of tigernut starch and meet the demand for industrial starch, the influence of dry heat treatment (130 °C for 2 h and 4 h, 7% moisture) on the functional properties and structure of tigernut starch alone and mixed with Chinese quince seed gum (1% w/w) was investigated. Modifying the starch significantly (p < 0.05) increased peak, trough and final viscosity, and reduced the swelling power and gelatinization enthalpy. In addition, the freeze–thaw stability and pseudoplastic flow were enhanced by this modification process. Microscopic and crystalline structure results indicate that dry heat treatment without gum destroys the surface and the internal crystals of the starch granules, but when gum was present, the granule becomes more resistant to dry-heating. Overall, the treatment with dry heat and the addition of Chinese quince seed gum improved the physicochemical properties of tigernut starch, in particular by increasing freeze–thaw stability and viscosity to expand the application of the starch in food industry.     

Preparation of epoxidized Eucommia ulmoides gum and its application in styrene‐butadiene rubber (SBR)/silica composites

In this article, we primarily introduced a method to prepare epoxidized Eucommia ulmoides gum (EEUG) and studied its application as interfacial additive in styrene‐butadiene rubber (SBR)/silica composites. We prepared the EEUG from the Eucommia gum extract solution using E. ulmoides leaves pretreated with enzymatic solutions as the raw material, petroleum ether as the solvent, and peracetic acid (CH₃COOOH) as the oxidant under a certain temperature. Accordingly, we focused on studying the effects of a series of factors, such as the mole ratio (γ) of peracetic acid to double bonds of Eucommia gum and reaction time on the epoxidation degree and crystallization degree of Eucommia gum in the epoxidation process, in order to control the properties of the EEUG. Regarding the study of the application of EEUG in SBR/silica composites, we found that the addition of EEUG greatly promoted the properties of SBR/silica composites by improving the dispersion of silica in SBR composites, which possessed excellent mechanical properties, including higher tensile strength, tear strength, 100 and 300% modulus, wear resistance, and low heat buildup. Copyright © 2016 John Wiley & Sons, Ltd.