Influence of oligosaccharides and polysaccharides on the properties and performances of defatted soybean flour-based adhesive.

Carbohydrates in defatted soybean meal significantly influence the performance of the prepared wood adhesives, though their specific roles remain unclear. Traditional method for this issue relied on the separation and recombination of proteins and carbohydrates, which was disturbed by the low separation yield and structural damage. This study proposed a stepwise removal approach using water and enzymatic treatments to systematically eliminate oligosaccharides and polysaccharides from defatted soybean meal. Characterization of the adhesives prepared with the treated defatted soybean meal revealed that carbohydrate removal increased adhesive viscosity, with polysaccharides exerting greater impact than oligosaccharides. Cross-linking analysis demonstrated higher reactivity of oligosaccharides compared to polysaccharides, though their cross-linked networks displayed inferior water resistance. Notably, both carbohydrate types negatively affected adhesive wet strength, with excessive polysaccharide removal causing viscosity-induced panel strength reduction. These findings elucidated carbohydrate functionality in defatted soybean meal-based adhesives, providing critical guidance for optimizing biomass utilization in sustainable adhesive development.