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Particle Size Distribution And Compositional Effects On Textural Properties And Appearance Of Dark Chocolates, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira

Professor Emmanuel Ohene Afoakwa

Particle size distribution (PSD) and composition in dark chocolate were varied and their effects on textural properties of molten and tempered chocolates determined using a TA.HD Plus Texture Analyzer. Surface colour was evaluated in terms of CIELAB parameters L*, C* and h° using a HunterLab Miniscan Colorimeter. Compositional parameters for particle size distribution were [D90 (>90% finer) of 18 ìm, 25 ìm, 35 ìm and 50 ìm], fat (25%, 30% and 35%) and lecithin (0.3% and 0.5%) contents. Results showed that PSD, fat and lecithin content significantly (p<0.05) influenced the textural parameters with significant interactions among factors. Particle size was inversely correlated with firmness (1235 - 173 g), consistency (50410 - 7029 g.s), cohesiveness (1594 - 262 g), index of viscosity (5737 - 1099 g.s) and hardness (7062 - 5546 g) with chocolates containing 25% fat and 0.3% lecithin. With higher fat and lecithin contents, PSD influence was reduced. PSD and fat concentration inversely influenced all colour measurements (L*, C* and h°) of samples. High correlations (r = 0.71 – 1.00, P<0.001) were observed between texture parameters and colour. It was concluded that PSD, fat and lecithin contents and their interactions were central to changes in textural properties and appearance during processing of dark chocolates.