Water for Food Drying: Geothermal Energy-Based Food Dryer

Different drying methods are practised worldwide for the preservation and longevity of herbs and other ingredients. The present work describes the concept of utilising renewable energy in the form of water, i.e. geothermal energy for food drying. In the current study, the notion is introduced and articulated for the first time in India. This study describes the demonstration of geothermal energy-based food dryer established in the Dholera region of Gujarat and its application in the drying of Ocimum sanctum (tulsi) leaf. The instrument is efficiently designed such that there are no hazardous emissions or extensive energy requirements for drying materials. Moreover, its uniqueness lies in the fact that low-temperature geothermal energy can be utilised as an energy source, and the drying conditions can be monitored as desired. Also, there is a uniform distribution of heat during drying, which helps to retain the structural behaviour of the products after drying. The investigation of moisture content and phytochemical analysis of geothermally dried tulsi leaf and its comparative study with other drying methods were done to evaluate the system’s integrity. The moisture content and phytochemicals of the geothermally dried leaf were found 16.6% and showed the presence of eugenol, camphene hydrate, farnesene, amorphene, etc. which are responsible for the medicinal and therapeutic significance of the leaf. Thus, enhanced preservation time and retention of essential phytoconstituents are justified through this technology.