Dark chocolates: Effects of emulsifier types and concentrations on physico-mechanical properties

Abstract

This study investigated the effects of post-conching blending with various emulsifiers on the physico-mechanical and sensory properties of dark chocolate. Polyglycerol polyricinoleate (PGPR), mono- and diglycerides (MD), soya lecithin (LSO) and sunflower lecithin (LSL) in three different concentrations were used. After conching, the emulsifier was mixed with 500 g of chocolate at a temperature of 50 °C and 500 rpm for 30 min using the Thermomix TM 6 mixer. The chocolates were evaluated in terms of particle size distribution, bending, acoustic, rheological, melting, colour and sensory properties. All emulsified chocolates exhibited reduced Casson plastic viscosity ( η c ) compared to the conched (STAN) and blended (MIX) samples, with the exception of PGPR_0.50. PGPR and MD showed higher viscosity values compared to lecithin samples. With increasing emulsifier concentration, a decrease in yield stress and thixotropy was observed for PGPR samples, while MD samples exhibited an increase in these parameters. In lecithin samples, a decrease in rheological parameters was observed up to the concentration of 0.50 w.%, while an increase in η c at 1.00 w.% was found. Particle size analysis revealed higher volume diameters Dv(90) for MD and PGPR samples (ranging from 18.60 to 23.30 μm) compared to LSO and LSL samples (from 18.30 to 19.00 μm). The melting temperature of the studied chocolates was determined using differential scanning calorimetry (DSC). In addition, cocoa butter polymorphs were observed using modulated DSC (MDSC). © 2026 The Authors.