An Insight Into the Role of Humidity and Temperature on Phenolic Retention, Powder Flow, Glass Transition, and Crystalline Changes During Non-centrifugal Sugar Drying

Abstract

Non-centrifugal sugars (NCS), traditionally obtained through open pan evaporation of cane juice, typically possess a moisture content ranging from 7% to 10% (wet basis). This study introduces a dehumidified drying technique aimed at significantly reducing moisture content, enhancing flow properties, minimizing antioxidant losses, increasing the glass transition temperature, and improving both the crystallinity and surface morphology of NCS. Two drying methods were evaluated: a solar dryer, with no control over temperature and humidity, and a refrigerated adsorption dehumidified dryer (RADD) with precise control of both parameters. The RADD achieved a substantial reduction in moisture content to 4.05% ± 0.2%, leading to markedly improved flow properties and a higher retention of phenolic content (82% ± 3.05%) compared to the solar dryer (71% ± 3.83%). Additionally, the RADD resulted in enhanced crystallinity, with a percentage of 83.5%, exceeding the 70%–75% range observed in solar-dried samples. Surface morphological analysis revealed that RADD-dried samples exhibited a uniform crystalline structure, whereas solar-dried samples displayed lumps and irregular particle shapes due to retained moisture. These findings highlight the practical implications of adopting dehumidified drying techniques for improving the quality of NCS. Future research should focus on exploring the scalability and energy efficiency of these techniques for industrial applications.