Enhancement of Lipase-catalyzed Synthesis of Caffeic Acid Phenethyl Ester in Ionic Liquid with DMSO Co-solvent☆

Caffeic acid phenethyl ester (CAPE) is a natural and rare ingredient with several biological activities, but its indus-trial production using lipase-catalyzed esterification of caffeic acid (CA) and 2-...     

茶叶中茶多糖茶多酚茶咖啡碱的高压脉冲电场快速提取

以10倍质量的0．001MEDTA缓冲液为提取液，应用高压脉冲电场（PEF）技术成功从等外绿茶中提取功能成分茶多糖、茶多酚和咖啡碱，并与水提法的提取率进行了比较。结果表明：在缓冲液pH9．5，场强度为25kV／cm，脉冲数为10的条件下，茶多糖有最大提取率，PEF法提取率是水提法的1．91倍；在缓冲液pH9．5，脉冲电场强度为25kV／cm，脉冲数为12时，茶多酚有最大提取率，提取率是水提法的1．11倍；在缓冲液pH4．0，脉冲电场强度为25kV／cm，脉冲数为10时，咖啡碱有最大提取率，是水提法的1．05倍。     

论欧美“科学咖啡馆”的实践及其启示

作为一种新型科学传播模式,科学咖啡馆在欧美国家越来越流行。它让科学家与普通公众聚集在休闲场所,在轻松愉快的氛围下讨论科学。它是一种公益性的草根运动,具备自发组织、低成本、平等性、灵活性等特点,赋予普通公众参与科学、评估科研的权利,体现了科学民主化趋势。虽然也存在一些困境,如听众身份、地域、资金等限制,但总的来说,其前景十分光明,对我国科普工作者颇有启发意义。     

Colour properties,stability, and free radical scavenging activity of jambolan (Syzygium cumini) fruit anthocyanins in a beverage model system: Natural and copigmented anthocyanins

The colour and stability properties of jambolan anthocyanins, both natural and copigmented forms, were investigated in beverage model as well as their radical scavenging ability. Natural anthocyanins of jambolan revealed low colour intensity due to glycosylation structure of the anthocyanins as diglucoside. The intermolecular copigmentation of anthocyanins with sinapic acid, caffeic acid, ferulic acid, and rosemary polyphenolic extract could enhance the colour intensity, which was observed through spectrometric parameters, such as hyperchromic effect (ΔA_vis-max) and bathochromic shift (Δλ_vis-max). In addition of sinapic acid, caffeic acid, and rosemary polyphenolics also increased the stability of the anthocyanin colour during exposure to white fluorescent light and storage at refrigeration and room temperatures, whereas on high thermal treatments, this phenomenon was not observed. Furthermore, beverage model coloured with natural or copigmented anthocyanins revealed DPPH radical-scavenging activity. The AEAC values indicated that the beverage models with copigmented anthocyanins had higher scavenging activity than the beverage with natural anthocyanins.     

从圣经原型视角解读《伤心咖啡馆之歌》

卡森·麦卡勒斯是美国南方代表作家之一。她深受美国南方宗教氛围影响,在《伤心咖啡馆之歌》中大量地运用了圣经主题、场景和人物原型,并通过对这些原型的"置换变形"和"魔幻变调",极大地加深了作品的深度,表达了强烈的宗教意识,使其具有永恒的艺术魅力。