In connection with the constant growth of demand for high-quality food products, there is a need to develop effective methods for storing agricultural products, and the registration and predicting infection in the early stages. The studying of the physical properties of infected plants and seeds has fundamental importance for determining crop losses, conducting a survey of diseases, and assessing the effectiveness of their control (assessment of the resistance of crops and varieties, the effect of fungicides, etc.). Presently, photoluminescent methods for diagnosing seeds in the ultraviolet and visible ranges have not been studied. For research, seeds of winter wheat were selected, and were infected with one of the most common and dangerous diseases for plants—fusarium. The research of luminescence was carried out based on a hardware–software complex consisting of a multifunctional spectrofluorometer “Fluorat-02-Panorama”, a computer with software “Panorama Pro” installed, and an external camera for the samples under study. Spectra were obtained with a diagnostic range of winter wheat seeds of 220–400 nm. Based on the results obtained for winter wheat seeds, it is possible to further develop a method for determining the degree of fusarium infection.

The development of technology for objectively determining the ripeness of plant seeds is an urgent task of modern agricultural production. An alternative to existing methods is optical photoluminescent technology, which is characterized by high accuracy, selectivity, expressiveness, as well as being remote and non-destructive. The spectral characteristics of excitation and photoluminescence of wheat, oat, and corn seeds during their maturation were measured using a spectrofluorometer using a previously developed technique. It was found that during maturation, the short-wave component of the excitation spectra decreases (λs=362 nm) and the long-wave component increases (λl=485 nm). After measuring the luminescence spectra, the integral photoluminescence fluxes for long-wave and short-wave excitation, as well as their ratio, were determined. We have obtained statistically reliable linear regression models of the dependence of long-wave and short-wave photoluminescence flows on the maturation time. Based on the obtained dependencies, a technology was developed for determining the degree of physiological maturation and making decisions about harvesting ripe seeds. It includes sample preparation, excitation and registration of luminescent radiation, amplification of the received signals and their relations, obtaining information about the degree of ripeness taking into account a priori dependencies.

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A number of experimental studies were conducted on seeds of agricultural plants and of their grindings in order to adapt the photoluminescent method for controlling the bulk food products quality indicators. The spectra were measured according to a technique previously developed by the authors. The spectral characteristics of excitation and of the luminescence of products of different humidity are qualitatively similar, but with increasing humidity, the curves shift down. The excitation and luminescence spectra of grindings shift down with an increase in the average diameter of grinding particles. The developed technologies for photoluminescent control include sample preparation, luminescence excitation at a wavelength of 424 nm, its registration in the range of 450–650 nm, and amplification of the received electrical signal. Further, based on the previously established dependencies, humidity indicators or average particle diameters are determined, after which a decision is made as further actions to be conducted with the products. Practical applications The article shows the development of a photoluminescent method for controlling the humidity and the degree of grinding of bulk food products. These methods can be used for the objective control of parameters of bulk products in the technological processes of processing, storage, and cooking. To implement the methods, devices can be manufactured that can be recommended to the food industry.

The development and application of optical luminescent methods and devices will help obtain information quickly and objectively about the level of Fusarium infection of agricultural plants. For the previously obtained ranges, the spectral characteristics of excitation and luminescence of wheat, barley, and oats of various degrees of infection were measured. The obtained dependences of flows on infection were approximated by linear regression models and relative sensitivities were determined. For wheat and barley, it is advisable to determine the degree of infection by the ratio of flows Φλ1/Φλ2, which makes it possible to calibrate the measuring device in relative units and increase its sensitivity. A method for determining the degree of infected seeds with Fusarium was developed. After the seeds are placed in a light-tight chamber, they are excited by radiation, and photoluminescence is recorded. The electrical signal from the radiation receiver is amplified and processed accounting for previously obtained calibration curves. In the universal device that measures the infection of wheat, barley, and oats seeds, it is necessary to have three radiation sources: 362 nm, 424 nm, and 485 nm. Based on the energy efficiency criteria, optimal LEDs and photodiodes, as well as a microcontroller, switches, operational amplifiers, a display, and other components of the device, were selected.