Relationship between rheological, textural and melting properties of dark chocolate as infuenced by particle size distribution and composition
In dark chocolate, rheological properties during processing are influenced by particle size distribution (PSD), fat and lecithin contents with consequential effects on finished texture and melting characteristics. Multivariate regression, correlation and principal component analyses (PCA) were used to explore their interrelationships. A 4 x 3 x 2 factorial experiment was conducted with varying PSD [D90 (90% finer than this size) of 18ìm, 25ìm, 35ìm and 50ìm), fat (25%, 30% and 35%) and lecithin (0.3% and 0.5%). Rheological properties (yield stress and apparent viscosity), textural properties (firmness, index of viscosity and hardness) and melting index (duration) were respectively measured using shear rate-controlled rheometer, TA.HD Plus texture analyzer and differential scanning calorimetry. The PSD, fat and lecithin contents significantly influenced all rheological, textural properties and some melting characteristics. Increasing particles sizes reduced yield stress, apparent viscosity, firmness, index of viscosity, hardness and melting index of products with greatest influence with 25% fat and 0.3% lecithin, reduced with increasing fat and lecithin contents. There were high correlation (r = 0.78-0.99) and regression coefficients (R2 = 0.59-0.99) among the rheological, textural and melting index indicating their high inter-relationships. In PCA, the rheological, textural and melting index accounted for >95% variance in the data.
Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, and Joselio Vieira. "Relationship between rheological, textural and melting properties of dark chocolate as infuenced by particle size distribution and composition" European Food Research and Technology DOI 10.1007/s00217-008-0839-5 (2008): 1-9.
Available at: http://works.bepress.com/emmanueloheneafoakwa/79