Department of Agriculture

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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.
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.
Application Of ISO 22000 In Comparison With HACCP On Industrial Processing Of Milk Chocolate
(International Food Research Journal, 2013) Afoakwa, E. O; Mensah-Brown, H.; Crentsil, G. K.; Frimpong, K.; Asante, F.
Hazard analysis was conducted to identify critical control points (CCPs) during cocoa processing and milk chocolate manufacture and applied into a hazard analysis and critical control point (HACCP) plan. During the process, the different biological, physical and chemical hazards identified at each processing stage in the hazard analysis worksheet were incorporated into the HACCP plan to assess the risks associated with the processes. Physical hazards such as metals, stones, fibres, plastics and papers; chemical hazards such as pesticide residues, mycotoxins and heavy metals; and microbiological hazards such as Staphyloccous aureus, coliforms, Salmonella, Aspergillus and Penicillium were identified. ISO 22000 analysis was conducted for the determination of some pre-requisite programmes (PrPs) during the chocolate processing and compared with the HACCP system. The ISO 22000 Analysis worksheet reduced the CCPs for both cocoa processing and chocolate manufacture due to the elimination of the pre-requisite programmes (PrPs). Monitoring systems were established for the CCPs identified and these included preventive measures, critical limits, corrective actions, assignment of responsibilities and verification procedures. The incorporation of PrPs in the ISO 22000 made the system simple, more manageable and effective since a smaller number of CCPs were obtained.
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).
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.
Calculation Of Interfacial Tensions Between Macromolecular Solutions And Soltrol-130 From Contact Angles Measurements
(ARPN Journal of Engineering and Applied Sciences, 2013-02) Sinayobye, E.; Mensah-Brown, H.; Yaya, A.; Kakane, V. C. K.; Baryeh, E. A.
The determination of the surface tension of some liquids or solutions has been carried out using a tensiometer. The determination of the contact angle between the liquids and a planar surface has also been carried out using photography. Polar and dispersive contributions of the surface tension were obtained by calculation while the polarities of the liquids and solutions were determined applying Wu equations. This method gave the different results for solutions prepared from macromolecular compounds (acroleine - ethanolamine macromolecular solution 1g/l, acroleine - diethanolamine macromolecular solution 1g/l, polyglutaraldehyde-ethanolamine macromolecular solution 0.7 g/l and polyglutaraldehyde - diethanolamine macromolecular solution 1 g/l) synthesized by Malonda from glutaraldehyde and acroleine. The dispersive and polar contributions of the surface tension were computed and used to calculate the interfacial tensions of solutions by the simple measurement of the contact angle. The results have revealed that the computed interfacial tensions were comparable to the values measured directly by the tensiometer for polyglutaraldehyde- ethanolamine macromolecular solution 0.7 g/l and polyglutaraldehyde - diethanolamine macromolecular solution 1 g/l) making an interface with Soltrol-130 of 17.1 and 16.9 dynes/cm compared to direct measured values of 17.2 and 17.7 dynes/cm respectively representing 1% and 5% error, respectively.
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 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.
Variability In Biochemical Composition And Cell Wall Constituents Among Seven Varieties In Ghanaian Yam (Dioscorea Sp.) Germplasm
(African Journal of Food, Agriculture, Nutrition and Development, 2013-09) Afoakwa, E. O; Polycarp, D; Budu, A. S; Mensah-Brown, H; Otoo, E
This work characterized the most cultivated and consumed yam (Dioscorea) cultivars within the Ghanaian yam germplasm based on their biochemical and cell wall constituents to assess their potential alternative food and industrial processing applications. Samples were analyzed for their biochemical composition - starch, amylose, amylopectin, total sugars, reducing sugars and non-reducing sugars along the head, middle and tail regions of each tuber using standard analytical methods. Cell wall constituents - acid detergent fibre, neutral detergent fibre, acid detergent lignin, cellulose and hemicellulose of each tuber were also determined using standard analytical methods. The results showed no significant differences at p<0.05 in biochemical compositions along the length of the studied cultivars. D. cayenensis (Pure-yellow), D. rotundata (Pona) and D. alata (Matches) were found to have high starch contents (63.16-65.69%, 63.54-65.30% and 63.24-65.17% respectively). Amylose content was observed to vary along the length of the tubers for the varieties studied. D. alata (Matches) was observed to contain the highest amylose content of 19.66-20.64%. No identifiable trend was however, observed for the amylopectin content along the length between the varieties investigated. D. bulbifera recorded the lowest amylopectin content of 41.29%, 43.59% and 44.63% while D. esculenta had the highest with 49.84%, 50.24% and 50.13% along the tail, middle and head sections respectively. Total sugar content varied significantly (p<0.05) along the lengths of all the varieties investigated. It was higher at the tail portions for all the varieties studied than the head regions; the middle portions recorded the least. D. bulbifera recorded highest total sugar contents (4.74-4.84%) and total sucrose (3.58-3.64%). There were significant differences (p<0.05) in the cell wall constituents of the yam varieties. Cellulose was found to be the most common cell wall component with D. rotundata having the highest level of 3.36% whilst D. dumetorum had the least (1.56%). Hemicellulose content ranged between 0.42 g/100g in D. alata to 4.58 g/100g in D. esculenta whiles lignin content ranged from 1.56 g/100g in D. dumetorum to 2.87 g/100g for D. praehensalis. There were significant differences (p<0.05) in the neutral detergent fibre found in Dioscorea esculenta and the other yam species. It ranged from 1.18 g/100g in D. alata to 5.46 g/100g in D. esculenta. Less than 1% of acid detergent fibre was identified in the yam varieties, suggesting varied levels of biochemical composition and cell wall constituents in the different yam varieties.
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
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.
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.
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.
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.
The Influence Of Blanching, Anti-Browning Agent And Processing Time On Some Physico-Chemical Properties And Appearance Of Green Peppers (Capsicum Sinensis) During Canning
(African Journal of Food, Agriculture, Nutrition and Development, 2014-05) Mensah-Brown, H.; Afoakwa, E. O.; Hinneh, M.
Central Composite Rotatable Design (CCRD) was used to generate twenty combinations of these factors: blanching time, processing time and sodium metabisulphite concentration. The optimized conditions were then adapted for the canning process of green pepper. Blanching time ranged from 0-1 min whereas processing time and sodium metabisulphite concentration ranged from 10-30 min and 0-0.2%, respectively. The canned products were analyzed for physico-chemical qualities using standard analytical methods. Results obtained from various physico-chemical analyses showed variable trends and influences of the linear, quadratic and exponential interactions on the measured quality indices such as pH of the drained liquid, drained weight of the canned product, leached solids and colour of the canned products. The results showed significant (p≤0.05) quadratic effect of sodium metabisulphite as well as linear effect of blanching time on the drained weight of the canned green pepper. Generally, the pH of the medium decreased (increased acidity) with increasing processing time, which was also positively associated with the extent or amount of leaching. Additionally, all three factors were observed to have affected (to variable extent) the colour of the canned products. Blanching and processing times also affected the degree of browning. There was a strong significant (p≤0.05) influence of the quadratic factors of blanching time, processing time and sodium metabisulphite concentration on the colour properties (a-values, b-values and L-values) of the canned products. Statistical analysis showed significant (p≤0.05) linear effects of blanching time and sodium salt concentration as well as the combined effect of both factors on all the colour properties. All the studied parameters had significant regression coefficients (p≤0.05) suggesting the studied parameters contributed significantly to the observed changes. Colour of the canned products changed from green toward redness with increasing blanching time at all concentrations of sodium metabisulphite. Optimal processing combination of 0 min blanching time, 10 min processing time and sodium metabisulphite concentration of 0.2% produced a highly acceptable canned pepper product with preferred physico-chemical and appearance properties.
The Fermentation Characteristics Of Single And Mixed Yeast Cultures During Pito Wort Fermentation
(International Food Research Journal, 2015) Avicor, M. N.; Saalia, F. K; Djameh, C.; Sinayobye, E.; Mensah-Brown, H.; Essilfie, G.
Pito is an alcoholic beverage obtained through yeast fermentation of the wort extracted from sorghum malt. The production methods are largely artisanal and the product quality varies from batch to batch even for the same brewer. The use of starter culture is a plausible approach to minimizing the variability in product quality. This work compared the fermentation profile of single yeast and mixed yeast cultures in sorghum wort fermentation during pito production. A 2 x 3 factorial design was used to study the quality characteristics of wort pitched with single and mixed Culture yeast strains during 24, 48 and 72 hours alcoholic fermentation. The physicochemical properties, microbial load and sensory characteristics of samples were determined. Fermentation time had significant effects (p<0.05) on the pito characteristics. Pito color (of 12.5 and 16.5 EBC units) was different for single and mixed cultures respectively. Panelists perceived the colours of pito obtained from single yeast culture fermentation to be different from that obtained from mixed culture fermentation. Volatile aroma compounds identified during the fermentation period included esters (4), aldehydes (3), organic acids (2), alcohols (3) and a diacetyl. Both single and mixed cultures showed similar characteristics during wort fermentation.
Changes in some biochemical qualities during drying of pulp pre-conditioned and fermented cocoa (Theobroma Cacao) beans
(African Journal of Food, Agriculture, Nutrition and Development, 2015-01-01) Afoakwa, E. O; Kongor, J. E; Budu, A. S; Mensah-Brown, H; Takrama, J. F
Fermentation and drying are critical to the development of flavour precursors that generate into distinctive chocolate flavour notes during industrial manufacture. These processes also lead to reduction in acidity and free fatty acids of nibs, which dictates the levels of bitterness and colour development in chocolates. This study investigated changes in nib acidity, flavour precursors (sugars concentration and proteins) and free fatty acids during drying of pulp pre-conditioned and fermented cocoa beans using a 4 x 3 full factorial experimental design with pod storage (0, 3, 7 and 10 days) and drying time (0, 3 and 6 days) as the principal factors. Non-volatile (titratable) acidity, pH, sugars (reducing, non-reducing and total sugars), changes in protein content and free fatty acids of the beans were studied using standard analytical methods. Increasing pod storage consistently increased pH of the fermented nibs at the end of drying with consequential decrease in titratable acidity. The pH increased from 4.92 for the freshly harvested pods to 6.00 for pods stored for 10 days at the end of the drying process. Similarly, pH of the fermented beans increased with increasing drying time for all pod storage treatment except for pods stored for 10 days. The pH of fermented beans whose pods were stored for 3 and 7 days were 5.26 and 5.56 respectively after drying for 7 days. Protein, reducing sugars, non-reducing sugars and total sugars decreased significantly (p<0.05) with increasing duration of drying at all pod storage periods. Pod storage and drying significantly (p<0.05) increased the free fatty acids content of the fermented nibs. The FFAs of the dried beans increased from 0.47% for the unstored (freshly harvested) pods to 0.55% for pods stored for 3 and 7 days and 0.58% for pods stored for 10 days. However, FFAs content of all the dried fermented beans were below the acceptable limits of 1.75% oleic acid equivalent in cocoa butter at all pod storage periods. Storage of cocoa pod between 3–7 days with 7 days of drying (after 6 days fermentation) led to considerable reductions in nib acidity, reducing sugars, nonreducing, total sugars and proteins and acceptable FFA levels.
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.
Use of Paspalum Viginatum as an Alternative Growth Substrate for Oyster Mushroom Cultivation
(2017) Aboagye-Nuamah, Francis; Oppong, Joseph Bekoe; Bempah, Bernard; Akerimowo, Augustine A.; Nayenkun, Lawrence
The increasing demand for mushroom consumption worldwide calls for alternative growth substrates to ensure sustainable production. The study was conducted to evaluate the use of Paspalum vaginatum straw as an alternative growth substrate for the cultivation of oyster mushrooms (Pleurotus ostreatus), and to assess the effect of the growth substrate on the nutritional composition of the mushrooms. Six substrates were evaluated for the growth of the mushrooms. These were 100% Paspalum straw, Paspalum + sawdust (1:1), Paspalum + 5% rice bran, Paspalum + 10% rice bran, Paspalum + 20% rice bran, and 100% sawdust. The diameter of the mushroom cap, length of the stalk, total number and weight of fruiting bodies harvested were recorded. Proximate analysis was conducted to determine the moisture content, crude protein, total carbohydrates, fat, crude fibre, ash, Iron, Zinc, Calcium, Potassium, and Sodium contents of the mushrooms. The results indicated that the substrates significantly (p<0.01) influenced the number of days to first harvest, the size of the mushroom cap and the length of the stalk. The total number and weight of fruiting bodies harvested from the various substrates were not significantly different (p<0.05). This indicates that the yield of oyster mushrooms cultivated on the Paspalum was comparable to that of the sawdust which is widely used. The various substrates significantly affected the nutritional composition of the oyster mushrooms. Out of the six growth media, mushrooms cultivated on Paspalum straw substrate had the highest protein (61.3%) and Na (0.65mg) contents, but low in fat (0.1mg) and carbohydrates (14%). The mushrooms cultivated on sawdust recorded the highest fat content (0.59mg), Fe (10mg), Zn (6.9 mg) and Ca (0.77mg). Since the performance of the Paspalum in terms of the parameters studied were comparable to the sawdust, which has been the main substrate used for mushroom production, it can be concluded that P. vaginatum is a promising alternative substrate for the mushroom industry. The use of Paspalum for mushroom cultivation will reduce the dependence on sawdust.

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