Three-Dimensional Biomass Composites Using the Maillard Reaction Products of Molasses as a Binder

Abstract

Here we found that viscoelastic features of molasses facilitate paste formation with wheat bran and rice straw powders, and a subsequent heat treatment results in significant hardening with dehydration and the Maillard reaction. This simple two-step process (i.e., blending and heating) was beneficial to fabricate diverse 3-dimensional shapes. The hardening process displayed around 3.5, 0.5, and 2.5 MPa as compressive, tensile, and flexural strengths, respectively, when a 1:1 (v/v) ratio of molasses and the biomass powders was used. Instrumental analyses on molasses before and after the heat process and hardening with a model compound (i.e., gallic acid) revealed that structural transformations of molasses based on the Maillard reactions and concomitant coupling reactions with lignin or polyphenolic moieties from the biomass are crucial for the phenomenon. Practical functionalities such as antibacterial, nonbiodegradable, and virus particle-adsorbing properties potentially attributable to the lignin and melanoidin contents were also exhibited with the composites.