Effects of particle size distribution and composition on rheological properties of dark chocolate

Emmanuel Ohene Afoakwa, A. Paterson, Mark Fowler

Research output: Contribution to journalArticlepeer-review

129 Citations (Scopus)


Control of chocolate viscosity is vital to its quality and production cost, and directly influenced by solids particle size distribution (PSD) and composition. Effects of PSD and composition on rheological properties of molten dark chocolate were investigated by varying PSD [D90 (90% finer than this size) of 18, 25, 35 and 50 μm], fat 25, 30 and 35% and lecithin (0.3 and 0.5%) using a shear rate-controlled rheometer. PSD, fat and lecithin content significantly affected all rheological parameters, with significant interaction among factors. Increasing particles size gave significant reductions in Casson plastic viscosity, Casson yield value, yield stress, apparent viscosity and thixotropy, with greatest effect with 25% fat and 0.3% lecithin, which reduced with increasing fat and lecithin contents. Statistical analysis revealed that fat exerts the greatest effect on the variability in all the rheological properties followed by PSD and lecithin. PSD, fat and lecithin could be manipulated to control dark chocolate rheology, influencing quality whilst reducing production cost.
Original languageEnglish
Pages (from-to)1259-1268
Number of pages9
JournalEuropean Food Research and Technology
Issue number6
Publication statusPublished - Apr 2008


  • chocolate
  • rheology
  • plastic viscosity
  • yield stress
  • particle size distribution
  • emulsifiers


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