Effect of intermittent drying on the energy consumption and physiological quality of soybean seeds

Energy efficiency can be considered as one of the main components of sustainability. This study aimed to explore an alternative to reduce the energy consumption of drying process, besides to preserve the nutritional reserve of soybean seeds by applying intermittent drying. We dried soybean seeds in a fixed bed dryer and compared the conventional and intermittent operation results. Physiological quality of dried seeds was assessed in terms of germination, vigor, and fissure, in addition, the energy consumption of the operation was calculated. Results indicate a 46% reduction in energy consumption for intermittent operation in comparison to conventional drying for air temperature of 50°C and 42% for air temperature of 70°C. High temperature (70°C) caused a reduction in germination and vigor of seeds, accelerating deterioration, and compromising soybean quality. Practical applications Drying is essential to prolong the life of soybeans, reducing the typical postharvest moisture content. However, one of the main disadvantages of this technique is the high-energy consumption and the loss in the nutritional and physical-chemical quality of the final product compared to other methods of drying, especially at high drying temperatures. The global energy crisis and consumption of quality dry foods further challenge the development of innovative food drying techniques to deal with these difficulties. Intermittent drying is considered as one of the promising alternatives to improve energy efficiency and product quality without increasing the cost of the dryer. The results of this study show that the use of intermittent drying is an alternative that significantly contributes to reduce the energy demand of the process and contributes to the quality of dry soybeans in the field.