Development of a novel determination method for alginic acid

Abstract

Various determination methods for alginic acid have been developed for specific samples. As we were unable to directly compare the results of these methods, we developed a novel determination method. The procedure is as follows : ' extraction of dietary fiber fraction from samples ; ' selective extraction of alginic acid from the dietary fiber fraction ; and'colorimetric determination of alginic acid by carbazol-sulfuric acid reaction. When kelp (alginic acid content : 26.6 g/100 g) assessment was repeated 7 times, the intermediate precision (relative standard deviation) was 2.1%. The lower limit of determination was 0.1 g/100 g when using dextrin as a blank sample. Based on the present results, the trueness (mean recovery) ranged from 67.3% to 99.2% for 7 types of food.