Electrification of Oxidized Starch Production – Influence on Product Quality

Abstract

Industrial starch oxidations are commonly carried out using sodium hypochlorite (NaOCl). Electrification of this process via continuous generation of NaOCl from sodium chloride (NaCl) in situ has the potential to substantially lower the environmental impact thereof, as brine waste streams are reduced, while occupational health and safety risks associated with the use of NaOCl, such as during transport, handling, and storage, can also be minimized. In the present study, the influence of continuous electrochemical generation of NaOCl from NaCl on the quality of the starch oxidation process is evaluated based on measurements of oxidized starch carboxylate contents (DSCO2H), molecular weights (Mws), and pasting characteristics in comparison to those of commercially available reference oxidized starches produced by oxidation with NaOCl in batch suspension processes. Recycling of the NaCl solution and how this affects the quality of the oxidized starch products is also investigated. By successfully preparing oxidized granular starches almost identical to the reference starches, the results show that it is feasible to electrify the oxidation process and that the original NaCl chloride solution can be recycled at least four times for in situ electrochemical generation of NaOCl.