An Empirical Study on Convective Drying of Ginger Rhizomes Leveraging Environmental Stress Chambers and Linear Heat Conduction Methodology

Abstract

This comprehensive study provides an in-depth examination of the convective drying process and drying kinetics of ginger rhizomes (Zingiber officinale), precisely honing in on the influence of moisture content variation on the thermal property of thermal conductivity. Our research reveals a direct correlation between decreasing moisture content and thermal conductivity during drying, conducted under meticulously controlled conditions with a drying temperature range of 10 °C to 60 °C and an optimum drying temperature identified at 60 °C with a relative humidity of 35%. We scrutinise the thermal properties, namely, the thermal conductivity, in relation to moisture content, shedding light on the intricate dynamics involved. The study uncovers the distinct advantage of convective drying over traditional methods, shortening the drying time to just 24 h, compared to the nine and eight days required for open sun and solar tunnel drying, respectively. We identified optimal moisture levels for various ginger types: unblanched (6.63%, thermal conductivity 0.0553 W/m·K), blanched (9.04%, thermal conductivity 0.0516 W/m·K), peeled (8.56%, thermal conductivity 0.0483 W/m·K), and unpeeled ginger (5.98%, thermal conductivity 0.0460 W/m·K). As drying progressed, the moisture content fell from 81% to approximately 6–9%, concomitantly lowering the thermal conductivity from roughly 0.0553 W/m·K to around 0.0460–0.0516 W/m·K. These findings offer significant implications for the food industry, proposing improvements in drying processes and strategies for energy conservation when drying ginger rhizomes and similar agricultural produce. Moreover, this study sets a solid foundation for future investigations into potential applications of these insights to other agricultural products and various drying techniques.