Esterification of Quercetin Increases Its Transport Across Human Caco‐2 Cells

Plant polyphenols showed useful biochemical characteristics in vitro; however, the assessments of their clinical applications in vivo are restricted by their limited bioavailability due to their strong resistance to 1st‐pass effects during absorption. In order to improve the bioavailability of quercetin (QU), the ester derivative of QU (3,3′,4′,5,7‐pentahydroxy flavones, TAQU) was synthesized, followed by examining the oil–water partition coefficient as well as the transport mechanisms of QU and its ester derivative (TAQU) using human Caco‐2 cells. The transport characteristics of QU and TAQU transport under different conditions (different concentrations, time, pH, temperature, tight junctions, and potential transporters) were systematically investigated. Results showed that QU had a lower permeability coefficient (2.82 × 10^?6 cm/s) for apical‐to‐basolateral (AP‐BL) transport over 5 to 50 μM, whereas the transport rate for AP to BL flux of TAQU (5.23 × 10^?6 cm/s) was significantly greater than that of QU. Paracellular pathways were not involved during the transport of both QU and TAQU. QU was poorly absorbed by active transport, whereas TAQU was mostly absorbed by passive diffusion. Efflux transporters, P‐glycoproteins, multidrug resistance proteins were proven to participate in the transport process of QU, but not in that of TAQU. These results suggested that improving the lipophicity of QU by esterification could increase the transport of QU across Caco‐2 cells.     

魔芋葡甘聚糖的研究现状

魔芋葡甘聚糖是由D-葡萄糖和D-甘露糖以β-1,4糖苷键结合而成一种天然的高分子多糖,主要存在于魔芋块茎中。我国是魔芋生产大国,深度开发魔芋葡甘聚糖的应用途径,将会推动国民经济的发展。魔芋葡甘聚糖具有良好的吸水性、成膜性、胶凝性、保湿性以及降血压、降血脂等特殊的生理功效,在食品、医疗和化工等领域受到广泛应用。本文综述了魔芋葡甘聚糖应用现状和提纯方法,并分别从接枝共聚、氧化、交联、酯化等方面对魔芋葡甘聚糖化学修饰研究进行了阐述,以期为魔芋葡甘聚糖的进一步开发提供理论依据。     

基于有限差分法的食品包装材料不稳定性数值模拟

基于有限差分方法数值模拟了塑料食品包装材料化学物向食品(模拟物)的迁移及迁移物在食品内的不稳定性。利用数值计算软件Matlab进行数值模拟得出了不同损耗模式下的迁移预测曲线。结果表明,扩散系数D决定了迁移的动力学过程,分配系数K_(PF)表征平衡时化学物在包装材料和食品内的浓度比值,平衡时食品内的化学物浓度随化学物在包装材料内的初始浓度C_(in)的增加而增加。化学迁移物在食品内存在不稳定现象,这将导致实验结果低估其向食品的迁移。利用损耗函数得到了2种不同损耗模式下的迁移预测曲线。     

废旧涤棉类织物再利用技术的发展

再利用技术的发展是促进废旧纺织品回收再利用的根本。本文从纺织品与环境资源的关系着手,综述了近年来废旧涤棉类纺织品再利用技术方面的发展现状。分析后得出:涤棉类织物再利用技术发展较快;物理法从简单的机械利用向物理熔融和溶解多元化方向发展;化学法从传统的造纸或降解向生物质材料应用方向发展;生物酶解技术也得到了关注。另外,涤棉混纺织物从只利用涤纶或棉纤维的单一模式向综合利用发展,同时越来越多的跨学科研究融入到废旧涤棉织物再利用技术上来。目前,一些研究方法虽已初步应用,但由于技术的局限性,再利用情况仍不乐观。     

云南野生牛角瓜纤维的吸湿与吸水性

为了解云南野生牛角瓜纤维的吸湿与吸水性能,测试了这种纤维的标准回潮率、吸放湿曲线及吸水率,建立了吸、放湿回归方程和吸、放湿速率回归方程,并与棉纤维比较。结果显示：牛角瓜纤维比棉纤维有更好的吸湿性,其标准回潮率为１１.４％。牛角瓜纤维的吸湿滞后性大于棉,其吸、放湿行为可以用指数模型描,放湿速率显著高于棉纤维,吸湿与放湿平衡时间的差异更大。牛角瓜纤维比棉纤维的吸湿量和吸、放湿速率明显高,将使其织物有更好的穿着舒适性。牛角瓜纤维和棉纤维都表现出不易浸润的特性,但牛角瓜纤维的吸水率（１３３.６２％）明显高于棉（７４.９８％）,有作为吸水材料的潜在价值。     

Ball milling improves extractability and antioxidant properties of the active constituents of mushroom Inonotus obliquus powders

Inonotus obliquus has been used as a folk remedy for a long time. An improved method using fine grinding by ball mill was investigated, and the main chemical components and physicochemical properties of Inonotus obliquus powders were analysed. The Inonotus obliquus fine grinding powders were prepared by pulverising the coarse powder with planetary ball mill for different time. The results showed that the yields of polysaccharides increased from 41.08 mg g^?1 (coarse powder) to 319.62 mg g^?1, and the yields of polyphenols were also increased fourfold in ball‐milled powders as compared to the untreated one. Ball‐milled powders showed higher values in the bulk density, angles of repose and slide, water solubility index and swelling capacity (P < 0.05), but lower values in the water‐holding capacity and oil‐holding capacity. The shape and surface morphology of the powders were changed after ball mill treatment. The antioxidant properties of the extracts from ball‐milled powders were significantly improved (P < 0.05). The results will be helpful for the application of Inonotus obliquus in food and pharmaceutical industries.     

食品机械的防腐蚀措施

介绍了食品机械的腐蚀机理及其防止措施。     

打顶时间与留叶数对烤烟产质量及内在化学成分的影响

进行了不同打顶时间及留叶数的组合,对烟株叶片大小、株型等农艺性状,及烟叶产质量、内在化学成分等方面影响的试验.结果表明:在本试验设置的处理范围内,随着打顶时间的推迟和留叶数的增加,烟株的株高和节距呈逐步增加的趋势;打顶时间的早晚和留叶数的多少对中、下部叶片大小影响较小,但影响这些部位叶片的单叶重,对上二棚及顶叶的开片及单叶重都具有深刻的影响;留叶数偏少或打顶时间过迟,烟叶的产量会受到一定影响,而留叶数过多,均价、上等烟比例将受到影响,综合产、质量效益以留叶18-20片为最佳;另外,低留叶水平,推迟打顶时间对烟碱含量具有显著的降低作用,高留叶水平时,本试验设置的不同打顶时间对烟碱含量的影响不显著.     

甘蔗茎中化学元素的微区分布

用扫描电镜-能谱仪研究了甘蔗茎皮层的外表面和横切面中Si等元素的含量及分布.结果表明,皮层外表面不同形态区域中Si等元素的含量不同,颗粒物是Si高度密集的部位,Si的含量高达58.23%;平坦处的Si含量较低,为44.42%;颗粒物块及其连接处中所含Si的原子数相同,但所含C、O元素的原子数则相反.横切面中,皮层中Si的密度高且分布呈外层低里层高的规律性;维管束及薄壁细胞中Si的含量较低且分布较均匀,皮下纤维层中Si的含量最低,具有明显不同于麦秆的特点.实验结果预示不同部位中硅化物的组成及元素化学状态的差异.