Development of the enzyme reactor system with an amperometric detection and application to estimation of the incipient stage of spoilage of chicken

Abstract

An enzyme reactor system with an amperometric detection was developed for the determination of diamines, total concentration of putrescine, cadaverine and spermidine, and applied to the detection of the incipient stage of spoilage of chicken during storage at 5 and 15°C. The system was prepared from the combination of an enzyme reactor and an amperometric electrode for detection of hydrogen peroxide by the enzyme reaction. The reactor was packed with putrescine oxidase immobilized on chitosan porous beads. Response of the system was obtained for the three substrates, putrescine, cadaverine (97% of the response to putrescine) and spermidine (96%). The limit of detection is 0.01 mM for the three substrates, the relative standard deviation is 2.5% ( n=100) and the response is linear up to 1 mM ( R 2=0.992). One assay could be completed within 3 min. The immobilized enzyme was sufficiently stable for at least 8 months at 4°C and usable for at least 300 assays. As the saprophytic microorganisms were reached 10 7/g of chicken, generally recognized as the indication of the initial stage of putrefaction, the current response increased very rapidly because of the formation of diamines by microorganisms. These results suggest that the proposed reactor system provides a simple, rapid and economical method for the determination of incipient stage of spoilage.