Nanoparticle as a novel foam controller for enhanced protein separation from sweet potato starch wastewater

Abstract

This is an article describing a novel technology where hydrophobic nanoparticle acts as a foam controller to facilitate protein separation. Valuable sweet potato protein (SPP), a protein model, mainly exits in sweet potato starch wastewater (SPSW), and its separation is desperately needed to enable a sustainable utilization of waste and reduce the environmental burden. We firstly used hydrophobic silica nanoparticle (SNP) in situ modified by dodecyl dimethyl betaine (BS12) as a foam stabilizer instead of surfactants to improve SPSW foam stability. Somewhat unexpectedly, the particle also intensified the interfacial adsorption of SPP. Subsequently, a foam separation column with a vertical ellipsoid-shaped channel (VEC) was proposed to gently strengthen foam drainage and then enhance the enrichment ratio of SPP (ESPP). Most importantly, the negative impact of VEC on the recovery percentage of SPP (RSPP) was found to be negligible in the presence of modified SNP because it maintained the film thickness. After the foam separation, unmodified SNP served as a defoamer to accelerate bubble breakage. Eventually, RSPP and ESPP reached 80.6 ± 4.0% and 9.1 ± 0.5, respectively, using the SNP as a foam controller. We expect this technology to be a complementary and/or alternative strategy for protein separation.