Formulation engineering of water in cocoa – Butter emulsion

• Water in cocoa butter emulsions were prepared using a bench scale scraped surface heat exchanger followed by a pin stirrer.
• The effects of κ-carrageenan concentration and mix emulsifiers on properties of the emulsions were investigated.
• Droplet size and polymorphic form are determined by the rate of hydrocolloid gelation and the presence of lecithin.
• Overall, the incorporation of water droplets resulted in a monotonic decrease of the stress to fracture of the emulsions.
• The presence of lecithin favours droplets flocculation and as consequence the viscosity of the emulsions increases.

This research studied the effect of κ-carrageenan concentration and emulsifier mixture of soybean lecithin (LEC) and/or polyglycerol polyricinoleate (PGPR) on the physical properties of water-in-cocoa butter emulsions. Emulsions were prepared using bench scale margarine line process, consisting of a scraped surface heat exchanger and a pin stirrer. Results show that droplet size increases as the concentration of κ-carrageenan and/or LEC increases. Emulsions crystallise mainly in form V (β2), however when the concentration of κ-carrageenan increases to 1.5 wt% less stable polymorphic forms (II) were also observed. The rheological properties of the emulsions at 40 °C were mainly controlled by the concentration of LEC which causes droplets to flocculate and as consequence viscosity increases. Finally, behaviour under large deformation showed that the presence of water droplets weakens the emulsions structure, due to the reduction in the density of the cocoa butter matrix bearing the load.