Influence of lecithin-PGPR blends on the rheological properties of chocolate

Lecithin and polyglycerol polyricinoleate (PGPR) are common emulsifiers used in the manufacture of chocolate products. The effects of systematically varied blends of lecithin and PGPR added in a concentration up to 14 g/kg on the flow properties of melted dark and milk chocolate were determined by means of rotational rheometry. The results show that, independent of the total amount of the emulsifier, the yield stress of both dark and milk chocolate mass is most efficiently reduced by applying mixtures of approximately 30% lecithin and 70% PGPR. As regards total emulsifier concentrations between 4 and 6 g/kg, lowest viscosity values were found for lecithin-PGPR blends of 50:50 and 75:25 for dark chocolate and milk chocolate, respectively. The obtained results indicate that it is possible to tailor yield stress and viscosity of melted chocolate to specific requirements by the appropriate adjustment of both blending ratio and quantity of the emulsifiers.