Abstract
Recent progresses in the area of cryo-technology have come to develop cryo-milling process to be applied in food processing. Spices are interesting objects to apply this new process. First attempt has been made on nutmeg, which is highly difficult to mill from its oily and sticky nature. Milling temperatures tested were in the range from room temperature to -100°C and revolution rates were 3, 000r.p.m. and 5, 000r.p.m., A stamp mill was used to prepare a reference sample. It was impossible to mill nutmeg at the temperature above -20°C because of its highly sticky nature, but it was easily milled at the temperature below -40°C. Therefore it was shown that the efficiency of milling depends mainly on the milling temperature. In order to prevent the milled powder from sticking to the machine, the milling should be done at low temperature when those oily and sticky materials are milled. Compositions of nutmeg milled at various temperatures were rather identical. This will be explained by the supposition that volatile components are dissolved in nutmeg oil and their volatility become rather lower. Particle size distribution depended mainly on the revolution rate and faster revolution rate produced finer particles. At the same revolution rate, lower milling temperature resulted in finer particles.
