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Biosensor Based on Immobilized Nitrate Reductase for the Quantification of Nitrate Ions in Dry-Cured Ham

Abstract:

A nitrate reductase immobilized system with an oxygen electrode has been developed and optimized to determine the nitrate content in dry-cured ham. The obtained amperometric signal was recorded at 5 s in the immobilized nitrate reductase sensor and the reaction rates (slope) were related to the nitrate content. A linear relationship between the reduction nitrate rate by action of nitrate reductase and the nitrate concentration was found within the range 10–70 μM (R2 = 0.9761). The immobilized enzyme showed a high specificity and sensibility and was stable enough to allow the reutilization of the membranes up to eight times without loss of activity. This reduces the cost of the analysis as well as the necessary equipment that is cheap and the short average measurement time for each sample. The analysis of nitrate in dry-cured ham samples with the sensor and by HPLC revealed very good agreement (R2 = 0.971). The use of this sensor may constitute an interesting and valid alternative for the quantification of nitrate in dry-cured ham.