以市售酵母细胞壁为原料,考察不同提取工艺条件下酵母甘露聚糖的得率.结果表明,最佳提取条件为:料液比1∶60,115℃,浸提90 min,此时甘露聚糖最大得率可达到18.71%,影响因素的重要性依次为:料液比浸提温度浸提时间.对甘露聚糖进行初步纯化,结果显示Polar MC 60-Q型预装纯化柱的多糖损失率较低(38.21%),而蛋白去除率最高(90.97%),显示出较好的纯化效果.经初步纯化的甘露聚糖涂膜处理苹果显示出较好的抗褐变性能;保鲜剂组分为0.2%甘露聚糖、0.3%丙酸钙、0.3%抗坏血酸时,对葡萄进行涂膜处理,测得五日失重率为3.95%,较对照组降低19.70%,五日好果率77.78%,该配方保鲜效果明显优于其他测试组. 相似文献
A new chromophore, C1 , based on a similar DπA‐structure as in the FTC ‐chromophore but with a hydroxyalkyl spacer perpendicular to the direction of the dipole moment was synthesized. Both chromophores and the CLD ‐chromophore were used to prepare high Tg nonlinear optical vinyl polymers. The influence of the position of the spacer on the DπA‐system on the NLO response of the resulting polymers was investigated.
A straightforward modification of the resolution of the identity (RI) approximation to the Coulomb interaction is described. In the limit of basis sets that are dominated by high angular momentum functions the observed speedups in realistic test systems reach a factor of 2 compared to the standard RI algorithm, and a factor of up to 300 compared to the standard algorithm to form the Coulomb matrix. More moderate savings on the order of 0-20% are obtained for the more commonly used smaller basis sets. A series of test calculations is reported to illustrate the efficiency of the algorithm. 相似文献
The photooxidation of chloral was studied by infrared spectroscopy under steady-state conditions with irradiation of a blackblue fluorescent lamp (300 nm < λ < 400 nm, λmax = 360 nm) at 296 ± 2 K. The products were hydrogen chloride, carbon monoxide, carbon dioxide, and phosgen. The kinetic results reveal that the reaction proceeds via chain reaction of the Cl atom: The results lead to the conclusion that mechanism (B) is confirmed to be more likely than mechanism (A), which was favored at one time by Heicklen for the mechanism of the oxidation of trichloromethyl radicals by oxygen molecules: The ratio of the initial rates of CO and CO2 formation gave k7/k6 = 4.23M?1, and the lower limit of reaction (5) was found to be 3.7 × 108M?1 sec?1. 相似文献