An effective, green and mild deproteinization method for polysaccharides of Ruditapes philippinarum by attapulgite-based silk fibroin composite aerogel

Abstract

A large amount of protein impurity severely restricts the application of polysaccharides of Ruditapes philippinarum (PRP) in food and medicine. Moreover, the traditional Sevag deproteinization method always involves organic reagents. The purpose of this paper was to develop an effective, green and mild deproteinization method from PRP by attapulgite-based silk fibroin composite aerogel (ASA). Firstly, ASA was synthesized and applied to remove protein from PRP. Secondly, the deproteinization parameters were optimized with selectivity coefficient as index as follows: dose of ASA 1% and pH 7.0. Under these conditions, deproteinization ratio (Dr%), polysaccharide recovery ratio (Rr%) and selectivity coefficient (Kc) reached 79.44 ± 1.87%, 95.81 ± 2.95% and 18.95 ± 1.55, respectively. Next, the feasibility of ASA method was evaluated. As a result, ASA method not only achieved higher deproteinization efficiency in less time compared with Sevag method, but also retained structure and antioxidant activity of polysaccharides. ASA was also proven with recycling ability and could be reused more than five times. Furthermore, it was found that protein adsorption on ASA was better fitted by pseudo second-order kinetic and Freundlich model. Taking together, the data implied that ASA method would be promising of deproteinization from PRP suitable for polysaccharides processing.