The application of low temperature grinding shows promising pathway to produce higher quality ground product in terms of flavour and volatile oil retention of spices. The possibility of using evaporative water cooling for grinding chilli was studied to ascertain the quality parameters. Atomized water was sprayed on to the chilli pods being fed in to the mill. The temperature, moisture content and colour values of the ground product were measured and the values were compared with conventional grinding. The temperature of the conventionally ground and evaporative water cooled ground chilli were 58 ± 2.65 °C and 36 ± 1.5 °C respectively and the corresponding amounts of heat removed by water vapour were 29.33 kJ and 186.50 kJ. The moisture content of conventionally ground chilli and evaporative water cooled ground chilli with water spraying were 9.06 ± 0.41 and 9.65 ± 0.23 percent wet basis and the corresponding colour values were 49.19 ± 0.99 (L*), 17.35 ± 1.62 (a*), 23.38 ± 1.29 (b*) and 47.52 ± 1.74 (L*), 18.38 ± 0.14 (a*) and 26.93 ± 0.68 (b*). This study revealed that the water can be effectively used as a coolant for reducing temperature rise during grinding in order to preserve the quality of chilli.
Tropical Agricultural Research Vol. 26 (1): 189 – 194 (2014)