Changes of Na-, Ca- and Mg-content in Pectin Fractions of Radish Root during Soaking in Sodium Chloride Solution

Abstract

Changes of the Na-, Ca- and Mg-content in the aqueous pectin solution, prepared from radish root and placed in a dialyzing membrane tube, by soaking in sodium chloride solutions was investigated. Infrared spectroscopy and atomic absorption spectroscopy revealed that most of the carboxyl group in the pectic substance was easily changed into the Na-salt and both Ca and Mg in the pectin were replaced by Na of sodium chloride. From these results, it is assumed that the leak of Ca and Mg from the crude cell wall during salting of radish root for pickles manufacture, as reported in the previous paper, may be caused by the exchange of Ca and Mg with Na of sodium chloride, and also by the change of carboxyl group into Na-salt, in the tissue pectin.