DIFFUSION OF SUGAR IN MICROWAVE DENATURED SUGAR-BEET TISSUES

Microwave-enhanced sugar beet denaturation was investigated in terms of the effective diffusion coefficient of sugar in sugar beet tissues (D(e)), the extraction coefficient (k), and the inhibition coefficient (q) of sugar beet tissues for sugar beet disks denatured by microwave heating at the energy intensities of 216, 390, 540, 768, and 1170 kJ/kg, and by such chemicals as chloroform or carbon tetrachloride saturated at 20-degrees-C, respectively. A one-dimensional diffusion method was followed in this study. The D(e), k, and q values were from 8.62 x 10(-12) to 1.72 x 10(-10) m2/s, 5.67 x 10(-4) to 1.13 x 10(-2) l/min, and 0.02 to 0.40, respectively, for microwave energy intensities ranging from 216 to 11 70 kJ/kg. The effect of microwaves on beet denaturation at the intensity of 540 U/kg was statistically equivalent to scalding at 75-degrees-C for 30 min or to the 8-h treatment with chloroform or carbon tetrachloride saturated in 15% sugar solution at 20-degrees-C. The diffusion coefficient of sugar in beet tissues increased only 30% at the maximum for microwave energy intensity increasing from 540 to 11 70 kJ/kg. When intensity was below 540 kJ/kg, the sugar beet tissues were incompletely denatured Thus, the microwave intensity around 540 kJ/kg could be regarded as the minimum dosage for complete denaturation.