Effect of extraction techniques on properties of polysaccharides from Enteromorpha prolifera and their applicability in iron chelation

The structural characteristics of polysaccharides directly affect their property, function, and application. Enteromorpha prolifera, a resource-rich green alga, contains special sulfated rhamnose-rich polysaccharides. In this study, the physicochemical properties of polysaccharides extracted from E. prolifera using different techniques were compared, and significant differences in yield, molecular weight, and chemical composition were observed. The acid extraction had the highest extraction yield (24.7%), and the obtained polysaccharides (ACP) had a molecular weight of 41.1 kDa and sulfate content of 16.2%. ACP showed a good iron(III) chelating capacity, and after response surface optimization, the iron content of ACP-iron(III) complex reached 20.85%. According to the structure analysis, iron(III) was bound with hydroxyl and carboxyl of ACP. Soluble polysaccharides are the main component of E. prolifera tissue, easy to prepare, and with unique properties. The prepared ACP-iron(III) complex may be a powerful candidate for iron supplements.