Photoluminescent diagnostics of chickpeas

Abstract

High-quality seed material is a critical factor in the efficient production of grain and its products. Producing high-quality products requires more plant protein, a source of which is chickpeas. Quality control, which can be accomplished using optical methods, is of great importance when storing grain and seeds. The purpose of the current study was to validate the selection of informative spectral parameters to develop a photoluminescence diagnostic method for chickpeas. There were studied the optical spectral luminescence properties of middle-maturing chickpeas ‘Pamyat’ harvested in 2024, 2019, and 2017. Optical measurements were performed using a diffraction spectrum fluorimeter ‘CM2203’. There have been obtained excitation (absorption) and luminescence spectra. Chickpea excitation was in the range of 250–550 nm, with maxima at 362 and 424 nm for all samples studied. The greatest difference in the integral absorption parameter was in the excitation range of 370–500 nm. There were obtained integral parameters of the luminescence spectra at excitation wavelengths of 362 and 424 nm. Integral photoluminescence fluxes depended on storage time and percentage of protein and oil in seed. The error in determining the fluxes did not exceed 4.5 %. The most informative excitation wavelength was selected based on the condition of the maximum photo signal level, minimum error in determining the flux, and the greatest flux increase for different values of protein and oil percentage. The optimal excitation wavelength was 424 nm. The photoluminescence emission detection range for this excitation wavelength was 480–650 nm. The results obtained could form the basis to develop a photoluminescence method for monitoring chickpea parameters during long-term storage.