Decolorization of Japanese soy sauce (shoyu) using adsorption

► Systemic adsorption decolorizing of Japanese soy sauce was investigated. ► Activated carbon, activated clay and silica gel decolorized the soy sauce. ► Activated carbon showed a highest color reduction while maintaining sensory quality. ► Adsorption processes showed a same decolorizing characteristics from plots of Δa∗ vs Δb∗ and ΔC∗ vs ΔL∗.