K.S. Sandhu and Harsimran Singh
Department of Food Science and Technology, Guru Nanak Dev University, Amritsar - 143 005
Department of Food Science, College of Food Systems, P.O. Box 17555, UAE University, Al Ain, United Arab Empire
U. S. Shivhare*
Department of Chemical Engineering and Technology, Panjab University, Chandigarh - 160 014
Flow behaviour of concentrated watermelon juice was studied over a wide range of temperatures (30-70oC) and concentration (30-70oBrix). Results indicated that the power law model described well the shear stress-shear rate relationship. The concentrates exhibited shear-thinning behaviour. Variation of flow behaviour index (n) was not consistent and ranged between 0.199 and 0.342. Both consistency index (K) and apparent viscosity (h) decreased with increase in temperature and the activation energies of flow were found to be in the range of 7.61 to 22.99 kJ/mol.
Key words: Activation energy, power law model, rheology, watermelon juice concentrate.