Recent Advances in the Drying Process of Grains

Grain drying is a vital operation in preparing finished grain products such as flour, drinks, confectioneries and infant food. The grain drying kinetics is governed by the heat and mass transfer process between the grain and the environment. Incomplete, improper and over-drying are crucial to the grain quality and negatively influence the acceptance of the grain by the consumers. Dried grain moisture content is a critical factor for developing grain drying systems and selecting optimal performance by researchers and the grain processing industry. Many grain drying technologies such as fluidised bed dryers, fixed bed dryers, infrared dryers, microwave dryers, vacuum dryers and freeze dryers have been used in recent years. To improve the drying process of grain, researchers have combined some drying technologies such as microwave + hot air, infrared + hot air and microwave + a fluidised bed dryer. Also, they introduce some treatments such as ultrasound dielectric and dehumidification. These methods enhance the dryer performance, such as higher moisture removal, reduced processing time, higher energy efficiency and nutrient retention. Therefore, this review focused on the drying conditions, time, energy consumption, nutrient retention and cost associated with the reduction of moisture content in grain to a suitable safe level for further processing and storage.

Automated summary

Grain drying plays a crucial role in preparing finished grain products. The kinetics of grain drying is influenced by heat and mass transfer between the grain and the environment. Insufficient, improper, and excessive drying negatively affect grain quality and consumer acceptance. Various drying technologies have been used, such as fluidized bed dryers, infrared dryers, and microwave dryers. Combining different drying technologies and implementing treatments like ultrasound and dehumidification allows for higher moisture removal, shorter processing time, increased energy efficiency, and nutrient retention. This review focuses on the drying conditions, time, energy consumption, nutrient retention, and cost associated with reducing moisture content in grain for further processing and storage.