Influence of particle size on rheological properties of mango peel powder

Abstract

This study was envisaged to investigate the effect of particle size on the rheological characteristics of mango cv. Bangalora peel powder under ambient conditions using a rotational rheometer. The consequences of sample concentration, i.e., powder: water (1:4, 1:5, 1:6) was also evaluated. Sieve analysis using screens (420, 355, 250, 125 microns) was done to achieve the desired va riation in particle size. Shear stress-shear rate data was adequately fitted to Herschel-Bulkey, Power law and Casson law and the rheological properties were represented graphically by rheograms for 0 to 100 s-1 shear rate. Relative parameters and regression analysis against each model determined the flow characteristics of the samples. Selected three models showed well representation of the rheological data, with high regression coefficients. Model parameters (consistency coefficient, flow behaviour index and R2) validated the deviation in rheological characteristics with particle size and sample concentration. Shear stress (τ) increases steeply with sample concentration for equivalent particle size, however, for the same sample concentration, negative correlation of particle size with shear stress was reported. The identification of suitable particle size and sample concentration might be useful in understanding of rheological properties of the peel powder of selected cultivar.