Charge equilibria and pKa of malvidin-3-glucoside by electrophoresis
Charge equilibria and pKa of malvidin-3-glucoside by electrophoresis
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DOI：
10.1016/s0003-2697(03)00249-5
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发表时间：
2003-07-15
影响因子：
2.9
通讯作者：
Jones, GP
中科院分区：
文献类型：
--
作者：
Asenstorfer, RE;Iland, PG;Jones, GP
在pH 1.2至10.4范围内使用纸电泳测量锦葵色素-3-O-葡萄糖苷的表观pK（a）值，pKa（1）1.76 +/- 0.07，pK（a2）5.36 +/- 0.04，和pK（a3）8.39 +/- 0.07。使用缓冲水溶液和正辛醇之间的溶剂分配，还确定了锦葵素-3-O-葡萄糖苷的几个微pK（a）常数，突出了锦葵素-3-葡萄糖苷平衡的复杂性。作为一个非分光光度法的程序，电荷依赖的电泳迁移率方法提供了独立的信息，净电荷和颜色的花青素物种在葡萄酒的pH值（约。3.6）。在此pH值下，红葡萄酒中锦葵色素-3-葡萄糖苷的颜色仅与不带电的醌碱一致，作为平衡的主要有色组分。(C)2003 Elsevier Science（美国）。All rights reserved.
Paper electrophoresis has been used over the pH range 1.2 to 10.4 to measure apparent pK(a) values for malvidin-3-O-glucoside of pKa(1) 1.76 +/- 0.07, pK(a2) 5.36 +/- 0.04, and pK(a3) 8.39 +/- 0.07. Using solvent partitioning between buffered aqueous solutions and n-octanol, several micro-pK(a) constants for malvidin-3-O-glucoside were also identified, highlighting the complex nature of malvidin-3-glucoside equilibria. As a nonspectrophotometric procedure, the charge-dependent electrophoretic mobility method provided independent information on the net charge and color of anthocyanin species at wine pH (ca. 3.6). At this pH, the color of malvidin-3-glucoside in red wines is consistent only with the uncharged quinonoidal base as a major colored component of the equilibria. (C) 2003 Elsevier Science (USA). All rights reserved.