NOVELTY - Decomposition of eel involves performing enzymatic decomposition of eel using back bone, head and internal organs, removing solid contents, separating reaction liquid into light and heavy liquids, separating water-soluble protein component as diffused liquid, and concentrating proteolytic enzyme and unreacted protein contained in the residual liquid of diffused liquid to required concentration and recirculating.    USE - The method is used for processing residue of eel such as backbone and meat adhering to head and internal organs, and for producing oil and fat-soluble component, and water-soluble peptide and amino acid.    ADVANTAGE - The processed residue obtained by enzymatic decomposition is utilized effectively.    DETAILED DESCRIPTION - Continuous enzymatic decomposition of eel involves:    (i) mixing proteolytic enzyme (2) with processing residue of eel and performing enzymatic decomposition using back bone, head and internal organs as raw material (1), removing solid contents from the decomposition reaction liquid by solid-liquid-separator (5);    (ii) separating the reaction liquid into light liquid containing fat and oil (9) and heavy liquid containing water soluble protein component with a centrifuge; and    (iii) processing the heavy liquid using hole diffusion-type membrane separator and separating water-soluble protein component as diffused liquid.    The diffused water contains low molecular weight component of protein such as peptide and amino acid. The high molecular weight component of molecular weight 50000 or more such as proteolytic enzyme and unreacted protein are not diffused, and particles having diameter of 20 nm or more are separated as residual liquor. The low molecular weight components such as peptide and amino acid contained in the diffusion liquid are further concentrates. The method further involves concentrating proteolytic enzyme and unreacted protein contained in the residual liquid of diffused liquid to required concentration and recirculating.    DESCRIPTION OF DRAWING(S) - The figure shows the model diagram of continuous enzymatic decomposition method. (Drawing includes non-English language text).    Raw material (1)    Proteolytic enzymes (2)    Splitting columns (3)    Decomposition-reaction liquid (4)    Solid-liquid separator (5)    Solid content (6)    Reaction liquid (7)    Centrifuge (8)    Fat and oil (9)