Moisture‐dependent physical properties of Tacca involucrata tubers

Tacca involucrata Schum. and Thonn., a wild and rare plant, popular for its rich natural starch, is increasingly being used for food and medicine and hence needs to be commercialized in production and processing. Processing of its tubers into starch by wet extraction is not yet mechanized due to inadequate data on the physical properties of the crop. This study focused on determining the physical properties in order to obtain data needed for design of processing and storage systems. Physical properties were determined at five levels of moisture content for three‐dimensional classes (big, medium, and small). Geometric mean diameter decreased linearly from 81.53 to 68.69 mm, 68.23 to 56.93 mm, and 51.26 to 41.10 mm for the big, medium, and small tubers, respectively, with decreasing moisture content from 57.9 to 41.8% wb while sphericity of the big, medium, and small tubers, respectively, decreased polynomially from 0.794 to 0.761, 0.814 to 0.789, and 0.831 to 0.801. True density and bulk density however increased polynomially ranging from 1129.79 to 1202.32 kg/m³ and 510.92 to 641.30 kg/m³, respectively. The angle of repose decreased polynomially with same decrease in moisture content from 41.63 ° to 35.98 °, 39.18 ° to 36.86 °, and 38.85 ° to 35.09 ° for big, medium, and small tubers, respectively. The study established that all the properties are dependent on moisture content and followed trends reported for similar agricultural products. The data are useful in machine design for processing and handling and have implications on storage. PRACTICAL APPLICATIONS: Tacca involucrata is a wild plant that is used mostly for tubers and its seasonal nature due to noncommercialization is affecting its use for other purposes. This study investigated its properties with varying moisture contents with a view to understand its stability during storage. This will ensure its commercial production, availability for a longer period after harvest and eventual use for wide varieties of other applications.