Chemiluminescent Visualization for Evaluation of Gaseous Ethanol Distribution During ‘La France’ Pear Maturation

A 2-D visualization system for gaseous ethanol is constructed and tested in visualization of standard gaseous ethanol and maturation of fruit. This visualization system measures ethanol concentrations as intensities of chemiluminescence (CL) by luminol reaction induced by alcohol oxidase and a horseradish peroxidase-luminol-hydrogen peroxide system. Conversion of ethanol distribution and concentration to 2-D CL is conducted on an enzyme-immobilized mesh that contains alcohol oxidase, horseradish peroxidase and luminol solution. We visualize ethanol emission from a pear with maturation in which the concentration is typically at sub-parts per million (sub-ppm) level. Thus, a high-purity luminol sodium salt HG solution and an enhancer of fluorescence dye of eosin Y are optimized for the improvement of chemiluminescent intensity for visualization. The detection limit is improved sub-ppm using these solutions. Owing to high sensitivity, the emission of gaseous ethanol during La France pear (Pyruscommnis L.) maturation is successfully visualized and the intensity of each pixel is the reflection of ethanol concentrations. Therefore, this system is sufficiently useful for assessment of ethanol measurement for the maturation characteristic.