Effect of Moisture Content on Physical and Mechanical Properties of Turmeric (Curcuma longa) Rhizome

The design of equipment for harvesting, separating, cleaning, handling and storing of any agricultural commodity is influenced by its physical and mechanical properties. The physical properties and mechanical behaviour of turmeric rhizome were determined at different moisture content (6, 8 and 10 % on wet basis) under laboratory conditions. It was observed that physical properties increased linearly with increase in moisture content of rhizome such as length (54.46±8.45 to 55.79±8.61 mm), breadth (12.48±1.61 to 13.21±1.13 mm), thickness (11.32±1.41 to 11.65±1.00 mm), bulk density (555±0.84 to 563±2.54 kg/m3), true density (1337±2.91 to 1359±2.00 kg/m3), porosity (58.47±0.04 to 58.57±0.02 %), the angle of repose (35.87±0.02 to 37.42±0.04º). Mechanical properties coefficient of friction increased linearly (0.240±0.001 to 0.271±0.002) and rupture force decreased from 183.22±5.04 to 83.18±9.87 kg with an increase in moisture content of rhizome. The moisture content showed a significant effect on change in bulk density, true density, the angle of repose, the coefficient of friction and rupture force. However, properties like length, breadth, thickness and porosity are not significantly affected by moisture content.