Effect of moisture on physical and mechanical properties of cassia

Abstract

Cassia is one of the widely used spices in the Food Industry due to its preserving and flavoring qualities. Physico-mechanical properties of spices are crucial in the machine designing and processing operations. In this study, physical properties and hardness of cassia bark were determined at five moisture levels, 6–14% dry basis (d.b.). The hardness test was performed along three orthogonal axes of the cassia bark using a texture analyzer. The size of the cassia viz., length (34.79 mm), width (13.79 mm), thickness (2.84 mm), geometric mean diameter (11.13 mm), and sphericity (0.32) were examined at 11.10% d.b. moisture level. Bulk density (238.66–255.86 kg m−3), true density (691.82–795.13 kg m−3), porosity (65.50–67.82%), angle of repose (39.42–42.78°), and static coefficients of friction of cassia bark increased linearly with an increase in moisture. Moreover, static coefficients of friction ranged from 0.59 to 0.67, 0.50 to 0.66, and 0.48 to 0.56 for mild steel, plywood and aluminium surface, respectively. The hardness showed a linear decrease along each orthogonal axis with the rise in moisture and ranged from 48 to 211 N. Hardness was highest for the minor axis followed by major and intermediate axis at all the moisture levels. The results were statistical significance at (P ≤ 0.05) 95% confidence interval.

Keywords

• bulk density
• cassia
• hardness
• moisture content
• true density