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Plant Sciences

Food Chemistry and Quality Control

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Full-Text Articles in Social and Behavioral Sciences

Viscoelastic Properties And Pasting Characteristics Of Fermented Maize: Influence Of The Addition Of Malted Cereals, Dr. Emmanuel Ohene Afoakwa (Phd), Randy Adjonu, Justice Asomaning Dec 2009

Viscoelastic Properties And Pasting Characteristics Of Fermented Maize: Influence Of The Addition Of Malted Cereals, Dr. Emmanuel Ohene Afoakwa (Phd), Randy Adjonu, Justice Asomaning

Professor Emmanuel Ohene Afoakwa

Investigations were conducted on the viscoelastic properties and pasting characteristics of fermented maize with malted cereals and their suitability for infant feeding. A 3x3x2 factorial experimental design with malting time, cereal malt concentration and cereal type was used. Maize, millet, and sorghum malts were added to fermented maize to reducing its bulk density. Samples were analysed for their viscoelastic properties and pasting characteristics using Brabender Viscoamylograph. Sorghum malt in comparison to millet and maize malts was not effective in terms of lowering the hot and cold paste viscosities of the fermented maize. Maize and millet malts liquefied the dough considerably …


Acidification And Starch Behaviour During Co-Fermentation Of Cassava And Soybean Into Gari., Dr. Emmanuel Ohene Afoakwa (Phd), Edem John Kongor, George Annor, Randy Adjonu Dec 2009

Acidification And Starch Behaviour During Co-Fermentation Of Cassava And Soybean Into Gari., Dr. Emmanuel Ohene Afoakwa (Phd), Edem John Kongor, George Annor, Randy Adjonu

Professor Emmanuel Ohene Afoakwa

Changes in acidification and starch behaviour were investigated during co-fermentation of cassava and soybean into gari, an African fermented product. Non-volatile acidity, pH and starch content were evaluated using standard analytical methods. Starch breakdown and pasting characteristics were also analysed using Brabender Viscoamylograph. Fermentation caused significant variations in the pH, non-volatile acidity and starch concentration. The pH decreased with concomitant increases in non-volatile acidity during co-fermentation of the cassava dough. Soy-fortification upto 20% caused only minimal effects on the pH, titratable acidity and starch content during the fermentation period. Starch content decreased from 69.8%-60.4% within the 48 h fermentation time …


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.


Effects Of Cowpea Fortification, Dehydration Method And Storage Time On Some Quality Characteristics Of Maize-Based Traditional Weaning Foods., Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh, Esther Sakyi-Dawson Jun 2004

Effects Of Cowpea Fortification, Dehydration Method And Storage Time On Some Quality Characteristics Of Maize-Based Traditional Weaning Foods., Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh, Esther Sakyi-Dawson

Professor Emmanuel Ohene Afoakwa

Fortification of cereal-based traditional foods with legume protein can improve their nutritional value. It is, however, important to find out the extent to which the addition of cowpea affects the desirable quality characteristics of traditional weaning foods prepared from fermented maize and also to assess the effect of dehydration method and storage time on the chemical, physico-chemical and functional properties of the products. A 3 x 2 x 4 factorial experiment with cowpea level, drying method and storage time as the respective variables was done. The traditional weaning food was prepared by steeping maize in water for 24 hours, mixed …


Effect Of Nixtamalization On The Chemical And Functional Properties Of Maize, Samuel Sefa-Dedeh, Beatrice Cornelius, Emmanuel Ohene Afoakwa Mar 2004

Effect Of Nixtamalization On The Chemical And Functional Properties Of Maize, Samuel Sefa-Dedeh, Beatrice Cornelius, Emmanuel Ohene Afoakwa

Professor Emmanuel Ohene Afoakwa

The high utilization and consumption levels of maize in developing countries calls for investigations into new methods of processing to help introduce variety as well as improve the functionality and nutrient quality of maize-based foods. This study was carried out to determine the effect of nixtamalization on the chemical and functional characteristics of maize. A 2X4 factorial experimental design with cooking time (0, 30 min) and lime concentration (0, 0.33, 0.5 and 1.0%) was performed. Chemical composition (moisture, protein and ash), pH, titratable acidity, water absorption, colour, cooked paste viscosity and texture were determined using standard methods. The cooking time …


Effect Of Fermentation On The Quality Characteristics Of Nixtamalized Corn, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh, Beatrice Cornelius Apr 2003

Effect Of Fermentation On The Quality Characteristics Of Nixtamalized Corn, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh, Beatrice Cornelius

Professor Emmanuel Ohene Afoakwa

Spontaneous lactic acid fermentation is an important process in cereal processing. It is applied to develop and enhance taste and flavour, modify texture and improve the microbial safety of foods. When applied to nixtamalized corn mixed with traditional steeped corn it is expected to further improve the functionality, improve nutritional quality and provide an alternative corn-based ingredient. The objective of this study was to investigate the chemical and functional properties of fermented blends of steeped and nixtamalized corn. A 3_5 factorial experimental design with fermentation time (0, 24, 48 h) and blends composition (0:100, 25:75, 50:50, 75:25, 100:0 steeped:nixtamalized corn) …


Viscoelastic Properties And Changes In Pasting Characteristics Of Trifoliate Yam (Dioscorea Dumetorum) Starch After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh Sep 2002

Viscoelastic Properties And Changes In Pasting Characteristics Of Trifoliate Yam (Dioscorea Dumetorum) Starch After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh

Professor Emmanuel Ohene Afoakwa

Studies were conducted on the viscoelastic properties, as well as the changes in pasting characteristics, of trifoliate yam, Dioscorea dumetorum, starch during post-harvest hardening of the tubers. A 3x4 factorial experiment with blanching treatment time (0, 15 and 30 s) and storage time (0, 12, 24 and 36 h) as the respective variables was performed. The samples were evaluated for pasting temperature, viscosity at 95 _C, viscosity at 95 _C-Hold, viscosity at 50 _C and viscosity at 50 _C-Hold, as well as their changes during storage of the tubers, to determine the starch behaviour of the D. dumetorum tubers during …


Changes In Cell Wall Constituents And Mechanical Properties During Post-Harvest Hardening Of Trifoliate Yam Dioscorea Dumetorum (Kunth) Pax Tubers, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh Jul 2002

Changes In Cell Wall Constituents And Mechanical Properties During Post-Harvest Hardening Of Trifoliate Yam Dioscorea Dumetorum (Kunth) Pax Tubers, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh

Professor Emmanuel Ohene Afoakwa

In an attempt to investigate the changes leading to the rapid post-harvest hardening of the white cultivars of Dioscorea dumetorum tubers, alterations in the plant cell wall constituents and mechanical properties of the tubers were monitored. A 4x2 factorial experiment with storage time (0, 24, 48 and 72 h) and storage conditions [cold room (4 _C, 85–100% RH) and tropical ambient (28 _C, 62–100% RH)] as variables were performed. Harvested tubers were stored for 24, 48 and 72 h under 4 and 28 _C. Changes in mechanical properties, acid and neutral detergent fibres, lignin, cellulose and hemicellulose contents were monitored. …


Changes In Rheological Properties And Amylase Activities Of Trifoliate Yam, Dioscorea Dumetorum, Starch After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh May 2002

Changes In Rheological Properties And Amylase Activities Of Trifoliate Yam, Dioscorea Dumetorum, Starch After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh

Professor Emmanuel Ohene Afoakwa

Changes in rheological properties and amylase activities occurring in trifoliate yam, Dioscorea dumetorum, starch after harvest were investigated. Trifoliate yam tubers were harvested and stored under tropical ambient (28 _C) and cold room conditions (4 _C) for 12, 24 and 36 h. The D. dumetorum starches were extracted from the tubers under study and samples were evaluated for changes in their rheological properties (paste characteristics) during storage and to study the action of amylases on D. dumetorum starch after harvesting. The post-harvest activities of a and b-amylases were also studied to evaluate their rate of action on D. dumetorum starch. …


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 …


Chemical Composition And Quality Changes Occurring In Dioscorea Dumetorum Pax Tubers After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh Mar 2001

Chemical Composition And Quality Changes Occurring In Dioscorea Dumetorum Pax Tubers After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh

Professor Emmanuel Ohene Afoakwa

Studies were conducted on the chemical composition, as well as the biochemical and textural changes, occurring during storage of two cultivars of Dioscorea dumetorum yam tubers. The tubers were harvested and stored under tropical ambient (28_C) and cold room conditions (4_C) for 24, 48 and 72 h. The samples were evaluated for moisture, starch, sugars, fibres and textural properties. Chemical analysis showed no significant differences between the means obtained for moisture, ash, protein, fibre, fat, carbohydrate, calcium, phosphorus, iron, vitamin A and vitamin C contents of the cultivars (white and yellow) studied. During storage, moisture contents decreased by approximately 6–10% …