On the Difference of the Binding Properties to Inorganic Cations between High- and Low-Methoxyl Pectin

Abstract

The difference of cation-binding properties between high- and low-methoxyl pectin was investigated in detail by comparing with cation contents of K-, Na-, Mg-, Ca- and mixed-pectinates prepared from high- and low-methoxyl pectin. The pectinates used for the analysis were prepared as follows: the high-methoxyl pectin and low-methoxyl pectin solutions containing 1.0M KCl, 1.0M NaCl, 0.50M MgCl₂, 0.50M CaCl₂, or the mixture of these salts at the same concentrations as mentioned above, were allowed to stand for 3 hours at room temperature, and then dialyzed for 30 day. The cation content in the pectinates was determined by atomic absorption spectrometry. It was found that the cation content was in order of Mg>Ca>Na>K in the pectinate prepared from high-methoxyl pectin, while Ca>Mg>Na>K in the pectinate prepared from lowm-ethoxyl pectin. From these results, it was conluded that the binding properties of high-methoxyl and low-methoxyl pectin to cation were characterized as Mg>Ca>Na>K and Ca>Mg>Na>K, respectively.