A Comparative Study of Oven, Spouted Bed, and Convective Tunnel Drying Methods of Mango for Oil Production

Abstract

Mango seeds, with a high moisture content exceeding 70% (wet basis) require effective drying methods to ensure their preservation and to enhance the quality of derivative products like mango seed oil. Proper drying is essential to inhibit enzymatic activity and microbial growth, which extends the shelf life of these seeds. This study investigates multiple drying techniques, including conventional oven drying, spouted bed drying, and convective tunnel drying, to determine their effectiveness in moisture reduction, oil quality improvement, and microstructural transformation. Oven drying, a commonly used method, is simple but often leads to uneven drying and potential overheating, which can degrade oil quality. Advanced methods like spouted bed drying and convective tunnel drying show promise in addressing these challenges. Spouted bed drying facilitates uniform heat and mass transfer due to seed suspension, while convective tunnel drying offers controlled airflow and temperature conditions, enhancing moisture removal efficiency. The study uses scanning electron microscopy to examine the structural changes in mango seeds post-drying. The micrographs reveal that spouted bed drying and tunnel drying produce significant alterations in seed microstructure, creating pathways that improve oil diffusion. This structural optimization results in higher oil yield and quality, as indicated by key parameters such as free fatty acid content, peroxide value, and color stability. The findings emphasize the comparative advantages of advanced drying techniques over conventional methods. Spouted bed drying, in particular, emerges as a highly efficient technique for balancing moisture removal with preservation of oil quality. These insights contribute to the development of optimized drying protocols that maximize oil extraction potential while maintaining the nutritional and physicochemical properties of mango seed oil. By identifying optimal drying conditions, this research aids in advancing sustainable processing techniques for mango seeds, aligning with the goals of value addition and waste minimization in agro-industrial sectors.