Determination of amines in fresh and modified atmosphere packaged fruits using electrochemical biosensors

Natural amines in plants, endogenous constituents of tissues, are involved in different physiological processes such as fruit development and senescence. Their levels can vary depending on variety, ripening, and storage conditions. Moreover, microbial contamination results in the increase of the "biogenic" amine content of fruits and vegetables. Electrochemical biosensors for the determination of the amine content in fruits have been assembled using diamine oxidase and polyamine oxidase covalently immobilized onto polymeric membranes. Both enzymes in the presence of their substrates produced H2O2 that was detected at a platinum electrode polarized at +650 mV versus Ag/AgCl. The best analytical conditions for the two enzyme electrodes have been optimized. The main positive effect of packaging fresh fruits with polymeric films is the provision of a barrier to the gas diffusion; the reduced O-2 and increased CO2 concentrations slow the respiration rate. The films also allow the maintenance of high relative humidity with reduction of water loss. To investigate the postharvest life of apricots and sweet cherries in modified atmosphere storage at 0 degrees C, the concentration of amines in fruits packaged using different polymeric films was monitored.