High efficient preparation of low molecular weight galactomannan from Leucaena leucocephala galactomannan through the combination of hydrogen peroxide and oxalic acid

Researchers have always been interested in polysaccharide degradation because of the increased biological activity and usability following degradation. In this work, low molecular weight galactomannan (LMW-GM) was produced through the degradation of galactomannan by H2O2 and oxalic acid (OA). The optimal reaction conditions were found by conducting the response surface optimization experiment based on single-factor experiment and kinetics analysis. Under these conditions, the LMW-GM yield was 69.48 ± 1.02 %. Ultimately, an analysis of the degradation process revealed that OA attacked GM indiscriminately, and H2O2 has a stronger effect on the removal of branched chains while degrading GM. Hence, the degradation steps were rearranged as H2O2 was added 20 min before OA at a constant total time. The LMW-GM yield was successfully increased to 76.49 ± 1.27 %. The goal of this work is hopefully to give a theoretical foundation for the low-cost preparation and industrial production of the degradation of galactomannan.