APPLICABILITY OF VISCOSITY MEASURING METHOD TO THE DETECTION OF IRRADIATED SPICES

The conditions for measuring viscosity of spices to detect radiation treatment and the applicability of the method to various spices were investigated. Viscosities of black and white peppers, ginger and turmeric decreased depending upon dose, when they were measured after heat gelatinization at pH12. However, the viscosities of cinnamon and nutmeg did not show a dose dependent relation. The viscosity of irradiated onion powder was lower than that of unirradiated sample, when determined at pH5 without any heat treatment. A normalized viscosity parameter, viscosity/starch content (mPa.s/g of starch), resulted in a.most constant values for unirradiated black and white peppers, irrespective of the harvesting locality. The results in this study suggest that irradiated black and white peppers can be detected by viscosity measurement without any information about the harvesting locality.