Engineering properties of peeled and unpeeled garlic cloves

Garlic (Allium sativum L.) is widely used as a condiment and for medicinal and pharmaceutical preparations. The present study was undertaken to evaluate the engineering properties of garlic in both peeled and unpeeled form. The physical properties of whole garlic segments such as length, width, thickness were measured to estimate their geometric mean diameter and sphericity. Other properties such as bulk volume, bulk density, true density and porosity were also determined for both types of cloves. The experiments were also conducted to assess the frictional properties. Angle of repose and coefficient of external friction were determined against two surfaces, namely plywood and galvanized iron (GI) sheet. The average values of geometic mean diameter, sphericity, bulk density and true density for unpeeled and peeled cloves were measured as 11.820 mm, 0.494, 0.471 g/cc, 1.077 g/cc and 11.004mm, 0.526, 0.556g/cc, 1.169 g/cc, respectively. The coefficient of external friction for unpeeled cloves for plywood and GI surface were calculated as 0.366 and 0.772 and for peeled cloves as 0.664 and 0.812, respectively. The coefficient of internal friction for the unpeeled and peeled cloves were found to be 0.570 and 0.826, while the angle of repose values were calculated as 39.88 and 23.52 degrees, respectively. These properties are important for carrying out further operations of storage, transportation, design and development of peeling and other processing equipments.