Investigation of Solar Drying of Ginger (Zingiber officinale): Emprical Modelling, Drying Characteristics, and Quality Study

Abstract

Drying is a simultaneous heat and mass transfer energy intensive operation, widely used as a food preservation technique. In view of improper postharvest methods, energy constraint, and environmental impact of conventional drying methods, solar drying could be a practical, economical, and environmentally reliable alternative. In the present paper applicability of mixed mode solar cabinet dryer was investigated for drying of commercially important and export oriented ginger. Freshly harvested ginger slices were successfully dried from initial moisture content of 621.50 to 12.19% (d.b.) and their drying characteristics, quality parameters, and kinetics were evaluated. The results showed that present solar dryer could be successfully applied for drying of ginger in view of quality, reduced drying time, and zero energy requirement as compared to conventional open sun drying and convective drying techniques, respectively. Drying curves showed that drying occurred in falling rate period and no constant period was observed. The effective moisture diffusivity was determined by using Fick’s second law and found to be  m 2/s. The drying data was fitted to five thin layer drying models and compared using statistical criteria. Page model was found to be most suitable to describe the drying kinetics of ginger in solar dryer under natural convection among the tested models.