Browsing by Author "Mensah-Brown, Henry"

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Changes in Biochemical and Physico-chemical Qualities during Drying of Pulp Preconditioned and Fermented Cocoa (Theobroma cacao) Beans
(Journal of Nutritional Health & Food Science, 2014-04-28) Afoakwa, Emmanuel Ohene; Budu, Agnes Simpson; Mensah-Brown, Henry; Takrama, Jemmy Felix; Akomanyi, Evans
This study investigated the effects of post-harvest pod storage as a means of pulp preconditioning on the souring production, flavour precursors development and free fatty acids during drying of fermented Ghanaian cocoa beans. A 4 x 4 full factorial experiment was conducted with pod storage (0, 7, 14, 21 days) and drying times (0, 2, 4 and 6 days) as the principal factors. The souring/acidification indices (pH and titratable acidity), total sugar, total nitrogen and free fatty acids (FFA) were studied using standard analytical methods. The results showed that titratable acidity, total sugars and total nitrogen in cocoa beans decreased during drying and with increasing pod storage durations probably due to their participation in Maillard non- enzymatic reactions to form flavour volatiles and colour pigments as Amadori intermediates. By contrast, FFAs and pH increased during drying and with increasing pod storage durations. Pod storage for up to 7 days followed by 6 days of fermentation and drying respectively produced beans with acceptable FFA values below 1.75% whilst enhancing the flavour precursors development and reductions in nib acidity. However, these observed changes were more dependent on pod storage than on drying.
Changes in Nib Acidity, Proteolysis and Sugar Concentration as Influenced by Pod Storage and Roasting Conditions of Fermented Cocoa (Theobroma cacao) Beans
(Journal of Food Science and Engineering, 2013-12-20) Ofosu-Ansah, Eric; Budu, Agnes Simpson; Mensah-Brown, Henry; Takrama, Jemmy Felix; Afoakwa, Emmanuel Ohene
Changes in nib acidity, protein and sugar concentration during roasting of pulp pre-conditioned and fermented cocoa (Theobroma cacao) beans were investigated. A 4 × 4 full factorial design with the principal experimental factors as pod storage (0, 3, 7 and 10 d) and roasting time (0, 15, 30 and 45 min) were used. The roasted samples were evaluated for pH, titratable acidity, protein content and sugars concentrations using standard methods. Increasing pod storage caused consistent increases in pH with concomitant decreases in titratable acidity, whereas increasing roasting time caused only marginal and insignificant changes in pH but significantly decreased the titratable acidity. The protein content decreased significantly (P < 0.05) with increasing pod storage and roasting time. Reducing sugars increased marginally with increasing pod storage treatments whiles increasing roasting time significantly (P < 0.05) decreased the reducing sugars of the beans for all pod storage. The non-reducing sugar and total sugar content of the beans decreased significantly from 3.493 mg/g to 2.641 mg/g and from 9.284 mg/g to 8.891 mg/g, respectively, for pods stored from 0 to 10 days while roasting time caused slight decreases in non-reducing sugars with a considerable decrease in total sugars. Pod storage up to seven days decreased considerable the nib acidity (non-volatile acids), non-reducing sugars and total sugars while roasting up to 45 min at 120 °C caused dramatic decreases in the nib acidity and reducing sugars with only marginal decreases in non-reducing sugars and total sugars.
Effect of Roasting Conditions on the Browning Index and Appearance Properties of Pulp Pre-Conditioned and Fermented Cocoa (Theobroma Cacao) Beans
(Journal of Nutritional Health & Food Science, 2014-02-06) Afoakwa, Emmanuel Ohene; Budu, Agnes Simpson; Mensah-Brown, Henry; Takrama, Jemmy Felix; Ofosu-Ansah, Eric
Appearance is an important quality determinant of cocoa beans and it is used as standard criteria to establish the degree of fermentation and drying of the beans. Changes in browning index and colour (L*a* b*) during roasting of pulp pre-conditioned and fermented cocoa beans were studied using standard analytical methods. Increasing pod storage and roasting time at 120o C led to variable increases in browning index (BI) and b*-values of the beans with decreases in the L* and a* values. Cocoa pod stored for 10 days showed the highest BI (1.144) with the least L* value (24.15) whilst beans from the unstored pods showed the least BI (1.007) with the highest L* value (25.55). The rates of change in BI and colour (L*, a*, b*) were however more pronounced during roasting than pod storage. Brown pigment formation (BI) and the L* value were more pronounced after 30 minutes of roasting in beans from pods stored for 3 to 7 days. The colour changes in beans from 10 days pod storage was significant (p<0.05) after 45 minutes of roasting. The beans from the pods stored for 3 to 7 days showed consistent decrease in L* and a* values with increasing roasting time whiles the beans from the 10 days of pod storage were observed to produce lower L* value (darker beans) after 45 minutes of roasting. Pod storage between 3 to 7 days could be used to improve the brownness and appearance of roasted cocoa nibs. Beans from cocoa pod stored between 3 to 7 days produced the most acceptable BI and L* value after roasting for 30 minutes at 120o C.
Effects of Fermentation and Drying on the Fermentation Index and Cut Test of Pulp Pre-conditioned Ghanaian Cocoa (Theobroma cacao) Beans
(Journal of Food Science and Engineering, 2013-11-20) Kongor, John Edem; Takrama, Jemmy Felix; Budu, Agnes Simpson; Mensah-Brown, Henry; Afoakwa, Emmanuel Ohene
Investigations were conducted to establish effects of fermentation and drying on the fermentation index (FI) and cut test of pulp pre-conditioned Ghanaian cocoa beans using a 4  3 full factorial experimental design with the principal factors being pod storage (0, 3, 7 and 10 d) and fermentation time (0, 3 and 6 d) to study the changes occurring during the fermentation process. The study also used a 4  3 full factorial design with pod storage (0, 3, 7 and 10 d) and drying time (0, 3 and 7 d) being the principal factors investigated to study the changes occurring during the drying process. FI and cut test of the beans were studied during fermentation as well as the drying process. FI of the beans increased significantly with pod storage and fermentation but decreased slightly during drying. FI of the unfermented beans increased slightly from 0.674 for the unstored pods to 0.763 after 10 days of pod storage. The FI of the fermented beans (six days fermentation) also increased from 1.390 for the unstored pods to 1.424 for pods stored for 10 days. It decreased from 1.389 at the start of drying for the unstored pods to 1.105 for pods stored for 10 days at the end of drying (seven days). FI of all the beans were however, above 1.0 at the end of fermentation and drying for all pod storage treatments. Cut test revealed that storage of pods for 3, 7 and 10 days increased the percentage of brown beans by 66%, 94% and 72%, respectively, by the sixth day of fermentation. Percentage of brown beans decreased to 61%, 76% and 63%, respectively, for pods stored for 3, 7 and 10 d at the end of drying (seven days). Cocoa pods can be stored for up to 10 days, fermented for six days and dried for seven days with the necessary formation of brown pigments characteristics of well fermented and dried cocoa beans
Fermentation Capacity of Yeasts Using Mango (Mangifera indica Linn.) as Substrate
(Food Science and Quality Management, 2013) Kamassah, Anthony K.Q.; Saalia, Firibu K.; Osei-Fosu, Paul; Mensah-Brown, Henry; Sinayobye, Emmanuel; Tano-Debrah, Kwaku
The goal of this study was to address the problem of large post harvest losses of mangoes by employing yeast fermentation technology to produce a more stable, value-added product in this case fruit wine. The design of the study involved determination of the fermentative capabilities of four commercial yeast types on musts obtained from an improved (Keitt) mango cultivar that is popularly cultivated in some parts of Ghana for export. The characteristics of the mango musts that were monitored included total soluble solids (TSS), pH and total acidity (TA), microbial populations (aerophilic mesophiles, yeasts and Acetic acid Bacteria), alcohol content and colour over the course of the fermentations. Descriptive and hedonic sensory evaluation was carried out on the ferments obtained from all treatments. Results showed that two of the yeast types namely; Red Star Pasteur and Red Star Montrachet displayed superior fermentation characteristics and produced mango wines that were acceptable by both descriptive and affective sensory panels.
Optimization of Blanching Time, Sodium Metabisulphite (Na 2 S2O5 ) Concentration and Processing Time on Vitamin C Content, Microbial Quality and Sensory Characteristics during Canning of Green Pepper (Capsicum sinensis) Using Response Surface Methodology
(Journal of Food Science and Engineering, 2013-06-20) Afoakwa, Emmanuel Ohene; Mensah-Brown, Henry; Hinneh, Michael
Response surface methodology and central composite rotatable design (CCRD) for K = 3 were used to investigate the combined effect of blanching time (0-1 min), processing time (10-30 min) and sodium metabisulphite (Na 2S2O5) salt concentration (0%-2%) on vitamin C content, hardness (texture), microbial count and color intensity of green pepper (Capsicum sinensis) during canning. Blanching, processing time and sodium metabisulphite (Na 2S2O5) salt concentration all had variable effects on the vitamin C, microbial quality and sensory characteristics of the canned green peppers. Significant (P < 0.05) interactions were noted between all the factors with high regression coefficients (78.7%-97.0%). Increasing processing time caused significant decreases in vitamin C and microbial load of the product. However, salt concentration had only marginal and insignificant effect on the vitamin C content of the canned product. Sensory evaluation on the product showed that both the pre-processing conditions and of blanching and salt concentrations, and the processing time had varied effects on the color and hardness of the products. Hardness of the canned products generally decreased with increasing processing time and blanching time, while only minimal and insignificant effects were noted with blanching time. Increasing blanching time caused significant increasing retention of the dark green color of the peppers with only slight but insignificant increases noted with processing time, while increases in salt concentration consistently reduced the dark green color of the products. The optimum pre-processing and processing conditions that yielded products with high preference and consumer-acceptability were: blanching time of 0 min, processing time of 10 min and sodium metabisulphite concentration of 0.2%.
Optimization of the production of a chocolate-flavoured, soypeanut beverage with acceptable chemical and physicochemical properties using a three-component constrained extreme lattice mixture design.
(Food Science and Quality Management, 2014) Mensah-Brown, Henry; Afoakwa, Emmanuel Ohene; Wadie, Winifred Boahemaa
This study explored the feasibility of producing a soy-peanut, chocolate-flavoured milk beverage with acceptable chemical and physico-chemical properties from soybeans, peanuts and cocoa powder. Ten formulations were processed by mixing three basic ingredients: soybeans (20g/100g-80g/100g), peanuts (Arachis hypogaea L.) (20g/100g-60g/100g) and cocoa powder (1g/100g-7g/100g). The optimized proportions of the ingredients were obtained using a three-component, constrained extreme lattice mixture design. The optimized product consisted of 54.0-58.5% soybeans, 37.0-42.0% peanut and 4.46 - 4.48% cocoa powder and had an energy value of 124.103kJ/100g. Proximate analysis of the optimized products indicated that the beverage has a protein content of 2.77%, fat content of 1.38%, carbohydrate content of 1.26%, ash content of 0.32% and water content of 94.27%. This suggests that production of an acceptable full fat soy-peanut, chocolate-flavoured milk beverage is feasible through the optimization of the basic ingredients.
Optimization Of The Production Of Lubricating Oil From Re-Refined Used Lubricating Oil Using Response Surface Methodology
(ARPN Journal of Engineering and Applied Sciences, 2013-09) Mensah-Brown, Henry
Response surface methodology was successfully employed in the optimization of the production of lubricating oil from re-refined used lubricating oils. The re-refined lubricating oil was obtained from caustic treatment and vacuum distillation of used automotive gasoline engine lubricating oils. A 23 factorial design augmented with seven experimental points to form an orthogonal central composite design (CCD) to accommodate all second order effects was employed in this study. Lubricating oil additives namely oxidation/corrosion inhibitor, detergent and dispersant were used as independent variables. The extent of deterioration of the lubricating oil was investigated using neutralization number, sludge deposition and corrosion of carbon steel as responses. Optimal additive levels of 0.99% (v/v) oxidation/corrosion inhibitor, 1.33% (v/v) detergent and 3.0% (v/v) dispersant; were used with a blend of re-refined used lubricating oil and virgin bright lube stock in the ratio 3:1 to obtain an SAE 40 grade lubricating oil suitable for automotive gasoline engines.
The Physico-chemical Characteristics of Yeast Fermentation of two Mango (Mangifera indica Linn) Varieties.
(Food Science and Quality Management, 2013) Kamassah, Anthony K.Q.; Saalia, Firibu K.; Osei, Paul; Mensah-Brown, Henry; Sinayobye, Emmanuel; Tano-Debrah, Kwaku
Efficient methods of post harvest handling, preservation and value addition are critical for minimizing high losses in the post harvest chain of fruits. The goal of this study was to address this problem by employing yeast fermentation technology to produce a more stable, value added product from mangoes. The design of the study involved determination of the fermentative capabilities of a selected yeast strain on the quality characteristics of mango wine obtained from two selected mango cultivars (improved and wild) with and without peels. The response variables monitored in the must and wine included total soluble solids (TSS), pH and total acidity (TA), microbial populations (aerophilic mesophiles, yeasts and Acetic acid Bacteria), and alcohol content. Volatile compounds development was also monitored using GC-FID procedures. Descriptive and hedonic sensory evaluations were carried out on the mango wine obtained from all treatments. The effects of mango peels in must fermentation characteristics compared well with those of must fermented without peels. However, the wines made using peeled mangoes were far more preferred by consumers than wine made using mangoes with peels. Five (5) major classes of aromatic volatiles were identified in all must and wine samples. Acetaldehyde and ethyl caprylate were present in all treatments, followed by isobutyraldehyde and 2, 3 Butanedione. Some volatiles identified appeared to be mango cultivar specific (Benzaldehyde and 1-methyl-2-pyrrolidone) while other volatiles appeared to be unique to the yeast strain employed (Ethyl butyrate).
Re-Refining And Recycling Of Used Lubricating Oil
(ARPN Journal of Engineering and Applied Sciences, 2015-02-02) Mensah-Brown, Henry
The paper reviews the re-refining of used automotive engine lubricating oils to obtain lube stock with the right characteristics and additives’ response suitable for blending automotive engine lubricating oil. The caustic treatment and subsequent vacuum distillation method for re-refining of used automotive gasoline engine lubricating oils was used in this investigation. A lube stock with the appropriate properties and characteristics including additive response for the formulation of SAE 40 grade lubricating oil suitable for an automotive gasoline engine was obtained from a blend of rerefined used lubricating oil and virgin bright lube stock in the ratio 3:1. The lube stock had a viscosity index (VI) of 105.
Re-Refining And Recycling Of Used Lubricating Oil
(ARPN Journal of Engineering and Applied Sciences, 2015-02-02) Mensah-Brown, Henry
The paper reviews the re-refining of used automotive engine lubricating oils to obtain lube stock with the right characteristics and additives’ response suitable for blending automotive engine lubricating oil. The caustic treatment and subsequent vacuum distillation method for re-refining of used automotive gasoline engine lubricating oils was used in this investigation. A lube stock with the appropriate properties and characteristics including additive response for the formulation of SAE 40 grade lubricating oil suitable for an automotive gasoline engine was obtained from a blend of rerefined used lubricating oil and virgin bright lube stock in the ratio 3:1. The lube stock had a viscosity index (VI) of 105.
Risk Assessment Of Vacuum-Packed Pouched Tuna Chunks During Industrial Processing Using ISO 22000 And HACCP Systems
(International Food Research Journal, 2013) Afoakwa, E. O; Mensah-Brown, Henry; Budu, A. S.; Mensah, E.
Risk analysis was conducted during processing of Vacuum-Packed Pouched Tuna Chunks using HACCP systems. The hazards likely to occur and their levels of severity and chances of occurrences were identified. Critical control points, critical limits, control and preventive measures, corrective actions for non-conformances and verification procedures were evaluated and documented. ISO 22000 Analysis Worksheet was also employed for determination of some prerequisite programmes (PrPs) and compared with the HACCP decision tree table for determination of Critical Control Points (CCPs). The PrPs were the main difference between the two systems. The major hazards identified were the probable contamination with spoilage and pathogenic microorganisms - Listeria monocytogenes, Clostridium botulinum, Salmonella and Staphylococcus aureus; foreign materials - metal residues and sand; chemical contaminants - heavy metals, histamine and cleaning detergent residues, before, during and after processing. Using the HACCP decision tree, eight CCPs were identified, namely: fish receipt (CCP 1), frozen storage (CCP 2), racking and staging (CCP 3), metal detection (CCP 4), vacuum sealing (CCP 5), thickness rolling (CCP 6), retorting (CCP 7) and bulk incubation/seal testing (CCP 8). The incorporation of PrPs in the ISO 22000 made the system more flexible by reducing the number of CCPs (8 in the HACCP system) to 4 without compromising safety of the product.
Thermal Conductivity of Aqueous Mixtures of 2-n-Butoxyethanol at Pressures up to 150 MPa
(Journal of Chemical & Engineering Data, 2010) Mensah-Brown, Henry; Wakeham, William A.
This paper contains the results of new measurements of the thermal conductivity of mixtures of water and 2-n-butoxyethanol in the liquid phase within the temperature range of (304 to 346) K at pressures up to 150 MPa. The measurements were carried out with a transient hot-wire instrument and have an accuracy of ( 0.3 %. The investigation is the first conducted at high pressures on partially miscible mixtures whose components are of greatly differing thermal conductivity. It therefore provides a severe test of the methods of representing the thermal conductivity of liquid mixtures that are based on the hard-sphere theory of transport in liquids. It is shown that all of the experimental data may be represented to within ( 6 % by a “predictive” procedure based on the hard-sphere theory of liquids. However, a more detailed analysis of the results reveals small but systematic deviations from the universal behavior of the thermal conductivity as a function of molar volume that the predictive procedure and the hard-sphere theory have as their basis.