An advanced and universal method to high-efficiently deproteinize plant polysaccharides by dual-functional tannic acid-feIII complex

Deproteinization is a crucial step for the purification of polysaccharides from natural biomass. However, traditional deproteinization technologies often suffer from complicated operating processes and the usage of toxic chemical reagents. Herein, an advanced and universal deproteinization method based on dual-functional adsorbent consisted of preferential protein adsorption coating of tannic acid-Fe-III (TA-Fe-III) and magnetic Fe3O4 (Fe3O4@TA-Fe-III, abbreviated as FTF NPs) was developed. The proposed FTF NPs showed remarkable efficiency to remove protein from Lycium barbarum L. polysaccharides (LBPs) with deproteinization ratio of 96%, higher than the typical Sevag method (85%). Detailed adsorption kinetics studies demonstrated deproteinization process reached equilibrium after 10 min, faster than other reported deproteinization adsorbents. Furthermore, FTF NPs are structurally and functionally nondestructive as regards LBPs without using organic reagents. Also, it exhibited widespread-use deproteinization performance to several common plant species. Therefore, the proposed nano-separation based on TA-Fe-III complex is an advanced and universal tool to high-efficiently deproteinize plant polysaccharides.