In a method of producing a polymer composite, a polymer is provided in a liquid state such as a molten state. A plant material, such as soymeal, is provided that includes protein and carbohydrate. The plant material has a particle size less than 50 microns. A reactive protein denaturant is also provided. A dispersion of the plant material and the reactive protein denaturant is formed in a matrix of the liquid polymer. The plant material is reacted to bond with the reactive protein denaturant, and the reactive protein denaturant is reacted to bond with the polymer. The polymer is solidified to produce the polymer composite.