Optimisation of processing conditions and rheological properties using stephan mixer as conche in small-scale chocolate processing

Abstract

This study investigated the suitability of Stephan mixer for use as conche during small-scale chocolate production in an attempt to reduce cost and processing time. Molten chocolate was processed using the Stephan mixer under different temperature and time combinations and Buhler Elk'Olino conche (as reference), and the flow properties (Casson plastic viscosity, Casson yield stress and thixotropy) were studied using a shear-rate-controlled rheometer. Optimum settings of 65 °C for 10 min at 443 g dry conching followed by 50 °C for 15 min at 443 g wet conching in the Stephan mixer resulted in similar flow properties as the reference sample. Increasing the blade rotary speed for both dry and wet conching resulted in a decrease in flow properties. The Stephan mixer proved to be suitable for conching small-scale (approximately 1 kg) chocolate productions and could be explored as a fast and cost-effective method for small-scale chocolate conching processes. © 2013 Institute of Food Science and Technology.