UC Davis

The production of rice, a globally consumed staple food predominantly cultivated in Asia's humid climates, faces the challenge of efficient drying methods. Current drying technologies often involve a tradeoff—either consuming substantial energy or compromising rice quality, leading to significant food loss. This challenge underscores the need for an innovative, sustainable solution that can ensure food security, reduce energy consumption, and contribute to climate change mitigation. In response to these challenges, our integrated research across three studies introduces a novel approach in the form of Zeolite-based Drying Beads® (DB). In our approach, humid ambient air is channeled through a chamber filled with DB to extract moisture and produce warm, dry air. The dried air is subsequently directed through the paddy to reduce its moisture content to the targeted level. Our research indicates that DB has the potential to enhance energy efficiency in paddy drying processes, particularly evident in controlled laboratory settings across varying humidity conditions. DB's adaptability, especially during its regeneration phase, enables strategic energy use, aligning with periods of lower energy costs or the availability of renewable energy sources. In terms of rice quality, including total milling yield and color, DB has shown comparable results to conventional heated-air drying technologies under temperate drying conditions. Furthermore, the drying speed achieved with DB is also on par with these conventional methods. The study identifies several key limitations in the application of Zeolite-based Drying Beads® (DB) for paddy drying. A notable issue is the inconsistency in data standards within paddy drying literature, complicating effective comparisons between different drying methods and highlighting the need for standardized reporting on operational conditions, energy consumption, and rice quality. Additionally, the research reveals challenges with DB in high humidity environments, where excessive heat generation could potentially impact rice yield, underscoring the importance of managing drying conditions to maintain quality. The investigation also extends to the DB regeneration process, which, in this study, was limited to individual beads in a lab setting. This limitation points to the necessity for more comprehensive studies to evaluate the regeneration efficiency and practical application of DB in commercial settings, with a particular focus on how these systems can be integrated with renewable energy sources. These limitations, addressed in the subsequent chapters, point to the need for standardized data reporting, careful management of drying conditions, and further large-scale studies to fully understand and optimize DB's commercial viability and integration with renewable energy.