Experimental Investigation on Flow Properties of Muskmelon Pulp using Controlled Stress Rheometer

An experimental study was conducted on muskmelon fruit pulp using a controlled stress Rheometer. The flow behavior, Consistency index is calculated using the flow data of shear stress and shear strain. The pulp behaved thixotropic in nature. Three models are used to explain the flow behavior, viz. Casson, Ostwald and Herschel-Bulkley. Mathematical modeling of data from the curve of Shear Stress Vs Shear rate indicated that Herschel-Bulkley model fitted the best with correlation coefficient of 0.99. The stress required to indicate viscous nature is found to be 3.3 Pa as per Casson model, which precisely indicates the stress required to initiate flow. This behavior appears same as tomato ketchup or sauce flow from the thermally processed glass bottles. The thixotropic loop experiment has confirmed the solid nature of the pulp with a residual stress of 3.1 Pa. This data is useful to design equipment for thermal treatment of fruit pulp, fluid flow in heat exchangers of food processing lines and further reference studies of flow behavior of different fruit pulps.