APPLICATION OF REGULAR REGIME THEORY TO EVALUATION OF EFFECTIVE MOISTURE DIFFUSIVITY IN FRESH JAPANESE NOODLE (UDON)

摘要

Effective moisture diffusivity (Deff) of fresh Japanese noodle (fresh udon) wasrninvestigated to establish the optimal drying conditions in the drying process. Thernregular regime theory was applied to evaluate the Deff as a function of moisture contentrnand temperature under constant relative humidity (ca. 75%) and air velocity (1.7-1.8rnm/s) conditions at 20, 30 and 40°C using fresh udon with different initial moisturerncontent (0.43-0.58 kg/kg). The existence of regular regime period were experimentallyrnverified, where all drying curves merged into one curve regardless of initial moisturerncontent in each temperature. The Deff obtained was ranged from 2.1x10-11 to 3.7x10-rn11 m2/s, and was represented only as a function of temperature. The effect of moisturerncontent on Deff is negligibly small. The average activation energy of Deff wasrnestimated to be 21.3 Kj/mol, which was found to be similar to that of pasta.