Identification of UV-fluorescence components associated with and detection of surface damage in green pepper (Capsicum annum L)

Abstract

Fluorescence imaging has been used to detect fruit surface damage, but has not yet been applied to vegetables, such as green pepper. In this report, we extract and identify fluorescent components from the exocarp (skin) of green pepper. The fluorescence excitation and emission wavelengths of these extracted compounds were determined using a fluorescence spectrophotometer and identified using nuclear magnetic resonance spectroscopy and mass spectrometry. Red and blue fluorescent components with excitation and emission wavelengths 667 – 685 nm and 400 - 438 nm respectively, were found. In subsequent research, the red fluorescent compounds were targeted, as these compounds have a higher fluorescence intensity, around 97 a.u. Pheophytin a is one of these red fluorescent compounds, appearing in the mass spectrum at 871 m/z. Furthermore, when a fluorescence imaging system was set up, with halogen illumination, it was shown that this system could successfully detect surface damage in green pepper.