Optimisation of Process Parameters for Centrifugal Clarification of Sugarcane Juice for Quality Jaggery

Abstract

A solid-wall basket-type centrifugal clarifier of 500 l.h-1 capacity having a rotational speed of 1,200 rpm was used for the mechanical clarification of sugarcane juice. The effect of polypropylene filter pore size (5, 10, 15 μm), centrifugation time (5, 10, 15 min), and temperature of juice (60, 70, 80 ºC) on sugarcane juice clarification was studied using Box-Behnken design. Clarification efficiency ranged between 50.8% and 82.5%, whereas optical density (OD) and percent transmittance (%T) varied from 1.95 to 1.05 and 2 to 8, respectively. Optimisation of the process parameters suggested a polypropylene filter pore size of 10 μm, centrifugation time of 15 min, and juice temperature of 80 ºC, contributing to a solution of 82.5% clarification efficiency (ƞ). Jaggery prepared from clarified sugarcane juice appeared brighter in colour (L* value 58.1), and contained less amount of insoluble solids (0.75%) as compared to jaggery prepared from unclarified juice. No significant changes in sucrose and reducing sugar contents in jaggery were observed with clarification.