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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.


Effect Of Spontaneous Fermentation And Amylase Rich Flour (Arf) On The Nutritive Value, Functional And Viscoelastic Properties Of Cowpea-Fortified Nixtamalized Maize, Dr. Emmanuel Ohene Afoakwa (Phd), Philip Roger Aidoo, Randy Adjonu Apr 2010

Effect Of Spontaneous Fermentation And Amylase Rich Flour (Arf) On The Nutritive Value, Functional And Viscoelastic Properties Of Cowpea-Fortified Nixtamalized Maize, Dr. Emmanuel Ohene Afoakwa (Phd), Philip Roger Aidoo, Randy Adjonu

Professor Emmanuel Ohene Afoakwa

Studied were conducted to evaluate the combined effects of spontaneous fermentation and Amylase Rich Flours (ARF) on some nutritive value, functional and viscoelastic properties of cowpea-fortified nixtamalized maize. A 2x3x3 factorial design, with fermentation medium, fermentation time and ARF level was performed. The blends were fermented for the specific times and analysed for their titratable acidity, pH, water absorption capacity, viscoelastic properties, texture, protein and mineral content. Fermentation and ARF addition influenced titratable acidity, pH, water absorption, viscoelastic properties and texture of the cowpea-fortified nixtamalized maize. Addition of ARF decreased the viscoelastic properties, texture and pH of all the blends …


Response Surface Methodology For Studying The Quality Characteristics Of Cowpea (Vigna Unguiculata)-Based Tempeh., George Amponsah Annor, Esther Sakyi-Dawson, Samuel Sefa-Dedeh, Firibu Kwesi Saalia, Dr. Emmanuel Ohene Afoakwa (Phd), Kwaku Tano-Debrah, Agnes Simpson Budu Dec 2009

Response Surface Methodology For Studying The Quality Characteristics Of Cowpea (Vigna Unguiculata)-Based Tempeh., George Amponsah Annor, Esther Sakyi-Dawson, Samuel Sefa-Dedeh, Firibu Kwesi Saalia, Dr. Emmanuel Ohene Afoakwa (Phd), Kwaku Tano-Debrah, Agnes Simpson Budu

Professor Emmanuel Ohene Afoakwa

Response surface methodology was used to optimize the processing conditions in the preparation of cowpea tempeh. The independent factors studied were boiling time (varying from 5 to 30 min), incubation time (varying from 12 to 48 h) and incubation temperatures (varying from 25 to 50°C), whereas the dependent factors were protein content, protein solubility, pH, titratable acidity and total color difference (using L, a* and b*). Regression models were generated and adequacy was tested with regression coefficients (R2) and the lack-of-fit tests. Optimum processing conditions were determined by method of superimposition. There was a strong and significant influence (P < 0.01) of the quadratic effect of the incubation time on the protein content of the cowpea tempeh, with similar significance (P < 0.01) noted in protein solubility with increasing boiling time. The optimum processing conditions observed for the preparation of cowpea tempeh were boiling time of about 20 min, incubation time of about 28 h and incubation temperature of about 37°C.


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 …


Response Surface Methodology For Studying The Effect Of Processing Conditions On Some Nutritional And Textural Properties Of Bambara Groundnuts (Voandzei Subterranea) During Canning, Emmanuel Ohene Afoakwa, Agnes Simpson Budu, Alan Bullock Merson May 2007

Response Surface Methodology For Studying The Effect Of Processing Conditions On Some Nutritional And Textural Properties Of Bambara Groundnuts (Voandzei Subterranea) During Canning, Emmanuel Ohene Afoakwa, Agnes Simpson Budu, Alan Bullock Merson

Professor Emmanuel Ohene Afoakwa

The response surface methodology and central composite rotatable design for K=3 was used to study the combined effect of blanching, soaking and sodium hexametaphosphate salt concentration on moisture, ash, leached solids, phytates, tannins and hardness of bambara groundnut during canning. Regression models were developed to predict the effects of the processing parameters on the studied indices. Significant interactions were observed between all the factors with high regression coefficients (64.4-82.6%). Blanching and soaking of the seeds prior to canning led to increases in moisture content and leached solids, while significant decreases were observed for phytates, tannins and hardness of the canned …


Response Surface Methodology For Optimizing The Pre-Processing Conditions During Canning Of A Newly Developed And Promising Cowpea (Vigna Unguiculata) Variety, Emmanuel Ohene Afoakwa, Samuel Yenyi, Esther Sakyi-Dawson Dec 2005

Response Surface Methodology For Optimizing The Pre-Processing Conditions During Canning Of A Newly Developed And Promising Cowpea (Vigna Unguiculata) Variety, Emmanuel Ohene Afoakwa, Samuel Yenyi, Esther Sakyi-Dawson

Professor Emmanuel Ohene Afoakwa

Cowpea (IT87D195Y) seeds were canned with the objective of investigating the optimal pre-processing conditions that would yield the best quality canned product from the newly developed cowpea variety. Pre-canning procedures such as blanching time, soaking time and sodium hexametaphosphate [(NaPO3)6] salt concentration were used as the independent variables for a Central Composite Rotatable Design (CCRD). The pre-processing parameters obtained from the CCRD were used for the canning of the cowpeas and the quality characteristics (moisture content, pH of the drained liquid, drained weight, splitting of the seeds, leached solids and seed hardness) of the canned products were studied using response …


Application Of Response Surface Methodology For Studying The Product Characteristics Of Extruded Rice-Cowpea-Groundnut Blends, Emmanuel Asare, Samuel Sefa-Dedeh, Emmanuel Ohene Afoakwa Jul 2004

Application Of Response Surface Methodology For Studying The Product Characteristics Of Extruded Rice-Cowpea-Groundnut Blends, Emmanuel Asare, Samuel Sefa-Dedeh, Emmanuel Ohene Afoakwa

Professor Emmanuel Ohene Afoakwa

Response surface methodology (with central composite rotatable design for k=3 was used to investigate the product properties of extruded rice-cowpea-groundnut blends in a single screw extruder. The combined effect of cowpea (0-20%), groundnut (0-10%), and feed moisture (14-48%) levels were used for formulation of the products. The product moisture, expansion ratio, bulk density and total colour change were studied using standard analytical methods. Well-expanded rice-legume blend extrudates of less bulk density and lower moisture content were produced at low feed moisture. Increasing legume addition affected the various shades of colour in the product. Models developed for the indices gave R2 …


Influence Of Fermentation And Cowpea Steaming On Some Quality Characteristics Of Maize-Cowpea Blends, Samuel Sefa-Dedeh, Yvonne Kluvitse, Emmanuel Ohene Afoakwa Jul 2001

Influence Of Fermentation And Cowpea Steaming On Some Quality Characteristics Of Maize-Cowpea Blends, Samuel Sefa-Dedeh, Yvonne Kluvitse, Emmanuel Ohene Afoakwa

Professor Emmanuel Ohene Afoakwa

Fermentation and cowpea steaming can be used to improve the protein quality and quantity of fermented maize dough. In the production of maize-cowpea blends, it is important that the quality characteristics are evaluated to determine their functionality in the products. A 5x4x2x2 factorial experiment with cowpea level, fermentation time, cowpea steaming time and fermentation method as the variable was performed. The cowpeas were dehulled, steamed, dried at 65EC for 24 hours and milled into flours. Maize was soaked in water (18 hours), drained and milled into flour. The maize-cowpea blends were made into a 50% moisture dough, fermented for the …