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Professor Emmanuel Ohene Afoakwa

Chocolate

Articles 1 - 13 of 13

Full-Text Articles in Food Science

Enhancing Chocolate Flavour Quality – Effects Of Technological Modifications During Fermentation Of Ghanaian Cocoa Beans, Dr. Emmanuel Ohene Afoakwa (Phd) Oct 2010

Enhancing Chocolate Flavour Quality – Effects Of Technological Modifications During Fermentation Of Ghanaian Cocoa Beans, Dr. Emmanuel Ohene Afoakwa (Phd)

Professor Emmanuel Ohene Afoakwa

No abstract provided.


Quality Function Deployment During Industrial Chocolate Manufacture, Emmanuel Ohene Afoakwa May 2009

Quality Function Deployment During Industrial Chocolate Manufacture, Emmanuel Ohene Afoakwa

Professor Emmanuel Ohene Afoakwa

No abstract provided.


Microstructure And Mechanical Properties Related To Particle Size Distribution And Composition In Dark Chocolate, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira Feb 2009

Microstructure And Mechanical Properties Related To Particle Size Distribution And Composition In Dark Chocolate, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira

Professor Emmanuel Ohene Afoakwa

Composition in dark chocolate was varied and the effects determined on microstructure, using light microscopy, and mechanical properties of molten and tempered chocolates, using a TA.HD Plus Texture Analyser. Compositional parameters were particle size distribution (PSD) (D90 of 18, 25, 35 and 50 lm), fat (25%, 30% and 35%) and lecithin (0.3% and 0.5%) contents. Micrographs revealed wide variations in sugar crystalline network structure and inter-particle interaction strengths related to PSD and fat level. Samples containing 25% fat had more crystal agglomerates, well flocculated with greater particle-to-particle interaction strengths than those with higher (30% and 35%) fat contents. Increasing the …


Fat Bloom Development And Structure-Appearance Relationships During Storage Of Under-Tempered Dark Chocolates, Dr. Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira Dec 2008

Fat Bloom Development And Structure-Appearance Relationships During Storage Of Under-Tempered Dark Chocolates, Dr. Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira

Professor Emmanuel Ohene Afoakwa

Fat bloom development and associated changes in microstructure, texture, appearance and melting properties were studied. Dark chocolates varying in particle size (PS) (D90 of 18, 25, 35 and 50 µm) were processed and pre-crystallised to under-temper regime. Bloom was induced by storing products under ambient conditions (18 ± 2 °C, RH 50%) and changes in texture, surface whiteness, gloss and melting properties evaluated on cooling and after every 24 h in storage until reaching asymptotic values. Microstructure of products were characterised during blooming using stereoscopic binocular microscopy. Measurements on texture and surface whiteness showed initial rapid increases with consequential reductions …


Comparison Of Rheological Models For Determining Dark Chocolate Viscosity, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira Dec 2008

Comparison Of Rheological Models For Determining Dark Chocolate Viscosity, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira

Professor Emmanuel Ohene Afoakwa

Parameters in chocolate rheology, namely shear viscosity and yield stress, are important in manufacture and directly influenced by product particle size distribution (PSD) and composition. The Casson model was the standard confectionery industry strategy to quantify rheological properties of molten chocolate until in 2000, the International Confectionery Association recommended the use of interpolation data to describe viscosity. The two strategies are compared and correlated in defining rheological properties of molten dark chocolates prepared using different PSD, fat and lecithin content. Rheological parameters were determined using a shear rate-controlled rheometer and data examined using correlation, regression and principal component analyses to …


Modelling Tempering Behaviour Of Dark Chocolates From Varying Particle Size Distribution And Fat Content Using Response Surface Methodology, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira Sep 2008

Modelling Tempering Behaviour Of Dark Chocolates From Varying Particle Size Distribution And Fat Content Using Response Surface Methodology, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira

Professor Emmanuel Ohene Afoakwa

Central Composite Rotatable Design (CCRD) for K=2 was used to study the combined effects of multi-stage heat exchangers for Stages 1 (14–30 °C) and 2 (12–28 °C) coolant temperatures at constant Stage 3 coolant and holding temperatures during tempering of dark chocolates using laboratory-scale mini-temperer. Quantitative data on chocolate temper index (slope) were obtained for products with varying particle size distribution (PSD) (D90 of 18, 25, 35 and 50 μm) and fat (30% and 35%) content. Regression models generated using stepwise regression analyses were used to plot response surface curves, to study the tempering behaviour of products. The results showed …


Characterization Of Melting Properties In Dark Chocolates From Varying Particle Size Distribution And Composition Using Differential Scanning Calorimetry, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira Jul 2008

Characterization Of Melting Properties In Dark Chocolates From Varying Particle Size Distribution And Composition Using Differential Scanning Calorimetry, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira

Professor Emmanuel Ohene Afoakwa

Melting properties in dark chocolates processed from varying particle size distribution (PSD), fat and lecithin content were studied using differential scanning calorimetry (DSC). Compositional parameters were PSD (D90 (90% finer than this size) of 18, 25, 35 and 50 lm), fat (25%, 30% and 35%) and lecithin (0.3% and 0.5%) contents. Variations in PSD had no influence on crystallinity of products. Fat and lecithin content influenced the degree of crystallinity and melting properties (Tend, Tindex and DHmelt) of the products. Increasing fat content caused consistent increases in degree of crystallinity and crystal size distribution, thus effecting significant changes in Tend, …


Effects Of Tempering And Fat Crystallisation Behaviours On Microstructure, Mechanical Properties And Appearance In Dark Chocolates, Emmanuel Ohene Afoakwa Jun 2008

Effects Of Tempering And Fat Crystallisation Behaviours On Microstructure, Mechanical Properties And Appearance In Dark Chocolates, Emmanuel Ohene Afoakwa

Professor Emmanuel Ohene Afoakwa

No abstract provided.


Factors Influencing Quality Charateristics Of Chocolate Systems During Industrial Manufacture, Emmanuel Ohene Afoakwa Jun 2008

Factors Influencing Quality Charateristics Of Chocolate Systems During Industrial Manufacture, Emmanuel Ohene Afoakwa

Professor Emmanuel Ohene Afoakwa

No abstract provided.


Effects Of Tempering And Fat Crystalization Behaviours On Microstructure, Mechanical Properties And Appearance In Dark Chocolate Systems., Emmanuel Ohene Afoakwa, Alistaiar Paterson, Mark Fowler, Joselio Vieira Jun 2008

Effects Of Tempering And Fat Crystalization Behaviours On Microstructure, Mechanical Properties And Appearance In Dark Chocolate Systems., Emmanuel Ohene Afoakwa, Alistaiar Paterson, Mark Fowler, Joselio Vieira

Professor Emmanuel Ohene Afoakwa

Fat crystallisation behaviours in dark chocolates from varying particle size distribution (PSD) (D90 of 18, 25, 35 and 50 µm) was studied, yielding products from different temper regimes (optimal temper, over-temper and under-temper), and their effects on mechanical properties and appearance evaluated. Microstructures of derived products were determined using stereoscopic binocular microscopy. Wide variations in mechanical properties and appearance were noted in products from different particle size and temper regimes. Particle size (PS) was inversely related with texture and colour, with the greatest effects noted in hardness, stickiness and lightness at all temper regimes. Over-tempering caused significant increases in product …


Relationship Between Rheological, Textural And Melting Properties Of Dark Chocolate As Infuenced By Particle Size Distribution And Composition, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira Feb 2008

Relationship Between Rheological, Textural And Melting Properties Of Dark Chocolate As Infuenced By Particle Size Distribution And Composition, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira

Professor Emmanuel Ohene Afoakwa

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 …


Particle Size Distribution And Compositional Effects On Textural Properties And Appearance Of Dark Chocolates, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira Feb 2008

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.


Effects Of Particle Size Distribution And Composition On Rheological Properties Of Dark Chocolate, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler May 2007

Effects Of Particle Size Distribution And Composition On Rheological Properties Of Dark Chocolate, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler

Professor Emmanuel Ohene Afoakwa

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 lm], 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 …