Changes of chlorogenic acid content and its synthesis-associated genes expression in Xuehua pear fruit during development

According to synthetic pathway of plant chlorogenic acid （CGA）, the expression patterns of genes encoding enzymes that are associated with CGA synthesis were studied in normally developed Xuehua pear fruit. The study demonstrated that CGA content in peel and flesh of Xuehua pear decreased as fruit development progressed, with a higher level in peel. The expression levels of PbPAL 1, PbPAL2, PbC3H, PbC4H, Pb4CL 1, Pb4CL2, Pb4CL6, PbHC T1 and PbHC T3 genes decreased in fruit, which was consistent with the pattern of variation in CGA content. That indicated that these genes might be key genes for influencing fruit CGA synthesis in Xuehua pear. However, Pb4CL7 gene expression profile is not consistent with variation of CGA content, hence, it may not be a key gene involved in CGA synthesis.

魔芋葡甘聚糖改性研究进展

魔芋葡甘聚糖(konjac glucomannan,KGM)是魔芋中特有的天然无端基可溶性膳食纤维,具有改善肠道生态、清除巨噬M1内固醇、拮抗HIV逆转录等多种功能,在食品、医药、生物等众多领域有着良好的应用与发展前景。在KGM多元化产品生产与加工中,天然KGM因为溶解度低、溶胶稳定性差、凝胶可塑性弱等缺陷,需要从理化性质等方面进行深入分析,通过共混、物理和化学等改性方法加以改进。本文综述了近年来国内外魔芋葡甘聚糖改性方法的研究进展,提出了以KGM共混为基础的多糖、蛋白质类改性体系,对比了KGM物理改性的优缺点,构画出KGM的三种氧化及一种中间态结构、阐明了KGM接枝改性作用位点的变化及交联改性的现状,分析了KGM改性中值得关注和研究的问题,并展望了KGM改性未来发展和应用的趋势。