Improvements in drying technologies - Efficient solutions for cleaner production with higher energy efficiency and reduced emission

Drying is an integral part in the treatment of grains to maintain the freshness and good quality of agricultural products, while protecting bioactive substances (vitamins, antioxidants). The processing allows long-term and safe storage of products, but is one of the most energy-consuming steps in food production. Reducing drying costs by the proper energy management, including heat recovery and moisture removal from the drying air is the current challenge. The purpose of this review was to present recent innovations in seed and grain drying systems against the background of traditional techniques. The focus was on hybrid methods (microwave-assisted, infrared-assisted and ultrasound-assisted methods), which according to data can reduce non-renewable energy consumption by up to 80%. The implementation of innovations in drying is an important issue considering consumer health and environmental protection. Techniques applied for the exhaust gas purification from nitrogen oxides, sulphur oxides, carbon oxides, or volatile organic compounds by catalytic decomposition are also described. It also points out the possibility of using energy from renewable sources (solar energy, geothermal energy, energy from biomass combustion), minimizing the use of fossil fuels that have a negative impact on the environment. Dissemination of knowledge in this area is necessary for the implementation of innovative solutions on a large scale, which will allow development towards cleaner production.