Advancements in ginger drying technologies

Ginger (Zingiber officinale) is one of the most widely used spice cum medicinal herbs. The high initial moisture content of the freshly harvested ginger (85-90% wet basis) makes it difficult to store for a long time. Being a plant originated product there are always chances of fungal and microbial growth which are the most responsible factors in spoilage of the ginger globally. Solar drying is one of the most traditional, economic and environment -friendly methods used for the preservation of ginger by reducing the moisture content below 10% (wet basis). This study aims to review the present status of drying technologies developed and tested for the drying of ginger with a significant emphasis on solar drying technologies. Direct, indirect, mixed-mode, and hybrid solar dryers tested for ginger drying under natural and forced convection modes have been presented. A brief overview of studies on the solar and electrical drying of ginger with a glimpse of its quality, drying kinetics, economic and environmental aspects has been presented. This work would help researchers in design and development of the most suitable solar drying systems for ginger and other similar commodities.Practical application: Ginger is one of the most widely used spices and herbs around the world. It has a significant presence in the global food market and the postharvest losses are also substantial. This paper presents the current status of drying technologies developed for the preservation of ginger. This work would help researchers and farmers to understand the problems or requirements in ginger drying processes and developing solutions accordingly. The economic aspects of solar ginger dryers would be helpful in motivating farmers for accepting solar drying technologies which would also contribute to the global sustainable development goals suggested by the United Nations.