An improved processing method and system for producing tomato paste and other food products affected by viscosity. Tomatoes are processed into tomato juice. The juice is provided to a decanter that separates or fractionates the juice into two portions—a thicker, more viscous cake portion and a thinner, less viscous serum portion. The serum portion is concentrated by removing a portion of water using an evaporator such as a thin film or juice evaporator. The cake portion can be concentrated if necessary with a drier. The serum and cake portions are re-combined to produce a tomato paste having improved color, texture, flavor and nutrition.