STUDIES ON CRYOGENIC GRINDING OF CUMIN SEED

Studies on grinding of cumin seed at various cryogenic and ambient temperatures were conducted to observe its influence on volatile oil content and its components, particle size distribution, volume mean diameter and specific energy consumption. An increase in temperature in the cryogenic range (-160 to -70C) had no significant effect on volatile oil content, whereas increase in temperature in the ambient range (40 to 85C) significantly reduced the volatile oil content from 2.86 to 2.26 mL/100g. The volatile oil components, α-pinene, β-pinene, γ-terpinene, p-cymene and cuminaldehyde were not significantly affected by grinding temperature in the cryogenic temperature range. However, these components decreased significantly with increase in grinding temperature under ambient condition. With increase in temperature from -160 to -70C for 12 number of rotor ribs, the volume mean diameter of cumin powder increased quadratically from 129 to 164μm and the specific energy consumption increased from 72 to 108 kJ/kg.