共查询到18条相似文献，搜索用时 78 毫秒
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魔芋精粉中甘露聚糖含量的测定 总被引：2，自引：0，他引：2
魔芋精粉是由鲜魔芋块茎，经过干燥、机械粉碎、风选等工序得到的一种初级产品。魔芋精粉主要成分为甘露聚糖，其次还有淀粉、纤维素、蛋白质。游离还原糖等。魔芋甘露聚糖是由甘露糖和葡萄糖，通过β-（1→4）苷键和β-（1→3）苷键连接而成的高分子多糖（分子量达106）［1］。研究证明，魔芋甘露聚糖具有减肥作用，对血清胆固醇、肝胆固醇和中性脂肪的上升有明显的抑制作用，并具有调节代谢正常化和增强免疫功能的作用，被广泛应用于保健食品和医药上［2］。甘露聚糖含量是魔芋精粉质量的一个关键指标。目前，生产中仅以粘度的高低判断甘… 相似文献
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利用热风干燥装置,在风温50～80℃,风速0.5m/s,厚5～12.5mm,面积78.5cm2的条件下,研究了风温、厚度对魔芋甘露聚糖干燥特性和效率的影响,提出了魔芋甘露聚糖热风干燥工艺。 相似文献
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Nondestructive estimation of wood chemical composition of sections of radial wood strips by diffuse reflectance near infrared spectroscopy 总被引：2，自引：1，他引：2
P. David Jones Laurence R. Schimleck Gary F. Peter Richard F. Daniels Alexander Clark III 《Wood Science and Technology》2006,40(8):709-720
The use of calibrated near infrared (NIR) spectroscopy for predicting the chemical composition of Pinus taeda L. (loblolly pine) wood samples is investigated. Seventeen P. taeda radial strips, representing seven different sites were selected and NIR spectra were obtained from the radial longitudinal face of each strip. The spectra were obtained in 12.5 mm sections from pre-determined positions that represented juvenile wood (close to pith), transition wood (zone between juvenile and mature wood), and mature wood (close to bark). For these sections, cellulose, hemicellulose, lignin (acid soluble and insoluble), arabinan, galactan, glucan, mannan, and xylan contents were determined by standard analytical chemistry methods. Calibrations were developed for each chemical constituent using the NIR spectra, wood chemistry data and partial least squares (PLS) regression. Relationships were variable with the best results being obtained for cellulose, glucan, xylan, mannan, and lignin. Prediction errors were high and may be a consequence of the diverse origins of the samples in the test set. Further research with a larger number of samples is required to determine if prediction errors can be reduced. 相似文献
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Zhenfu Jin Youming Yu Shunliu Shao Jiewang Ye Lin Lin Kenji Iiyama 《Journal of Wood Science》2010,56(6):470-476
Cunninghamia lanceolata wood meal samples with different lignin contents after delignification with an acidic NaClO2 system were carboxymethylated, and the degree of substitution (DS) and the distribution of the carboxymethyl (CM) groups
were investigated by proton nuclear magnetic resonance (1H NMR) spectroscopy. Cellulose samples prepared from bleached kraft softwood pulp, food-grade konjac mannan, and commercial
oat xylan (containing 10% arabinosyl and 15% glucosyl residues) were also investigated. The chemical shift of methylene protons
in 1H NMR spectra of CM groups of carboxymethyl konjac mannan and commercial oat xylan appeared in the same region as those of
carboxymethylcellulose. The DS of carboxymethyl lignocellulose (CMLC) increased slightly from 1.36 to 1.48 with decreasing
lignin content, but the water solubility of CMLC clearly increased with decreasing lignin content. It was suggested that the
covalent linkages between lignin and cell-wall polysaccharides play the role of cross-linker in CMLC. Water absorbents were
synthesized by graft-copolymerization of acrylic acid onto CMLC samples with different lignin contents. The highest level
of water absorbency was obtained from CMLC containing 14% of lignin, suggesting the importance of lignin as the cross-linker. 相似文献
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Effects of pressure and temperature in the chamber during vacuum drying on the relative humidity and evaporation of wood surface were investigated by using the vacuum chamber. The setting temperature during vacuum drying included dry-bulb temperature td, the wet-bulb temperature tw and the temperature difference between the air in the vacuum chamber and the cooling water in the condenser. Results indicated that relative humidity during vacuum drying was affected by the dry-bulb temperature td, the wet-bulb temperature tw and the temperature difference between the air in the vacuum chamber and the water in the condenser. Relative humidity of wood decreased with the increase in temperature at the given temperature of the water in the condenser. The relative humidity was affected slightly by pressure in the vacuum chamber pA, and it decreased from 70% to 65% with pA increased from 50 kPa to 101 kPa. Moreover, there was nearly no evaporation under the vacuum without external heating. 相似文献
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普及型欧式木窗应用中空玻璃的性能分析 总被引：2，自引：2，他引：0
从人们对普及型欧式木窗与中空玻璃的需求出发，介绍了普及型欧式木窗和中空玻璃的性能，阐述了在普及型欧式木窗中应用中空玻璃的特点以及应注意的问题。 相似文献