Studies on evaluation of physical properties of turmeric (Curcuma longa L.) rhizomes (Var. Kesar)]

Abstract:

Turmeric (Curcuma longa L.) (var. Kesar) rhizome sample was divided into three grades (I: 25-45 mm, II: 46-66 mm, and III: 67-87 mm on the according to its major dimension for the study of physical properties. The average length, breadth and thickness of the samples ranged from 26.50 - 45.00 mm, 44.44 - 64.25mm and 40.20 - 84.99 mm for Grade I, Grade II and Grade III respectively. The geometric mean diameter, arithmetic mean diameter, square mean diameter, equivalent mean diameter, sphericity, aspect ratio, surface area, unit volume and shape factor ranged from 13.43 - 33.51mm, 20.97 -38.82 mm and 28.21 - 47.68 mm, 15.72 -34.61 mm, 27.65 - 41.15 mm, 30.19 - 52.23 mm, 24.81 =59.11 mm, 40.79 = 68.53 mm, 51.57 - 85.85 mm, 17.99 - 42.41mm, 29.80 - 49.24 mm, 37.06 - 61.92 mm, 43.22% - 87.57%, 37.26% - 79.91%, 41.30% - 73.57%, 0.29 - 0.96, 0.29 - 0.83, 0.27 - 0.72, 492.81 mm² - 3090.12 mm², 1276.59 mm² - 3997.86 mm², 2229.47 mm² - 6033.42 mm^2, 755.98 mm³ - 15582.37 mm³, 2723.92 mm³ - 21630.35 mm³, 6795.96 mm³ - 35926.89 mm³ and 0.03 - 0.11, 0.03 - 0.08, 0.03 - 0.05 for Grade I, II and III respectively. Among the gravimetric properties, thousand-rhizome weight averaged 14.043 kg. The bulk density decreased from 457.2 kg m⁻³ (Grade I) to 432.6 kg m⁻³ (Grade II) and 395.4 kg m⁻³ (Grade III). True density ranged from 1060 to 1102 kg m⁻³ with mean values of 1079, 1060 and 1102 kg m⁻³ for Grades I, II and III, respectively. Porosity increased with rhizome size, recording mean values of 57.6%, 59.2% and 64.1% for Grades I, II and III, respectively. The results of the study will be helpful in designing cleaners, sorters, graders, packaging and storage systems or equipment.