title: Flow system for fish freshness determination based on double multi-enzyme reactor electrodes.
abstract: A double reactor system for the determination of fish and shellfish freshness using the freshness indicator, K-value (K=[(HxR+Hx)/(ATP+ADP+AMP+IMP+HxR+Hx)]x100), was developed, where ATP, ADP, AMP, IMP, HxR and Hx are adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, inosine monophosphate, inosine and hypoxanthine, respectively. The system consisted of a pair of enzyme reactors with an oxygen electrode positioned close to the respective reactor. The enzyme reactor (I) was packed with nucleoside phosphorylase and xanthine oxidase immobilized simultaneously on chitosan beads (immobilized enzyme A). Similarly, the enzyme reactor (II) was packed with immobilized enzyme A and immobilized enzyme B (co-immobilized alkaline phosphatase and adenosine deaminase). Moreover, this reactor consisted of two layers, the enzyme A and enzyme B (1:1). A good correlation was obtained between K values, which were determination by the proposed system and by the HPLC method. One assay could be completed within 5 min. The signal for the determination of K value of fish and shellfish was reproducible within 2.3%. The long-term stability of the enzyme reactors was evaluated at 30 degrees C for 28 days.
authors.affiliation: Department of Life Sciences, Faculty of Life Sciences and Bio-Nano Electronics Research Center, Toyo University, 1-1-1 Izumino Itakura-machi, Ora-gun, Gunma 374-0193, Japan. okuma@itakura.toyo.ac.jp
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Okuma
authors.forename: Etsuo
authors.initials: E
authors.lastname: Watanabe
mesh_terms: D000243:Adenosine Deaminase; D000255:Adenosine Triphosphate / Q000032:analysis; D000469:Alkaline Phosphatase; D000818:Animals; D019149:Bioreactors; D015374:Biosensing Techniques; D002851:Chromatography, High Pressure Liquid; D004582:Electronics, Medical; D004800:Enzymes, Immobilized; D005399:Fishes; D005504:Food Analysis / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D010430:Pentosyltransferases; D015203:Reproducibility of Results; D017747:Seafood; D014969:Xanthine Oxidase
chemical_list: D004800:Enzymes, Immobilized; D000255:Adenosine Triphosphate; D014969:Xanthine Oxidase; D010430:Pentosyltransferases; C067995:nucleoside phosphorylase; D000469:Alkaline Phosphatase; D000243:Adenosine Deaminase