Evaluation of different storage processes of passion fruit (Passiflora edulis Sims) using a new dual biosensor platform based on a conducting polymer

In this work, we present a new electrochemical biosensor array for the evaluation of pH changes and total polyphenols content based on a conductive polymer used to immobilize anthraquinone-2-carboxylic acid (ANTQ), on the first electrode, and Trametes versicolor laccase on the second one. In particular, the anthraquinone based electrode was sensitive to pH changes detected through potentiometric measurements, while the laccase-based electrode was used to detect the total polyphenols content by using amperometry. After a preliminary characterization of both electrodes, the so prepared array was used to monitor the variation of pH and polyphenols content in different samples of purple passion fruit (Passiflora edulis Sims) stored post harvesting at different temperatures such as room temperature, 4 ºC and -20 ºC.