Browsing by Author "Asare, E.K."
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Item Application of response surface methodology for studying the product characteristics of extruded rice-cowpea-groundnut blends(International Journal of Food Sciences and Nutrition, 2004-09) Asare, E.K.; Sefa-Dedeh, S.; Sakyi-Dawson, E.; Afoakwa, E.O.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 values ranging from 52.8% (for the b-value) to 86.5% (for bulk density). The models developed suggested that the optimal process variables for the production of a puffed snack with an enhanced nutrition and spongy structure from a rice-cowpea-groundnut blend are low feed moisture of 14-20% and maximum additions of 20% cowpea and 10% groundnut. A lack-of-fit test showed no significance, indicating that the models adequately fitted the data. © 2004 Taylor & Francis Ltd.Item Extrusion cooking of rice-groundnut-cowpea mixtures - effects of extruder characteristics on nutritive value and physico-functional properties of extrudates using response surface methodology(Journal of Food Processing and Preservation, 2012-10) Asare, E.K.; Sefa-Dedeh, S.; Afoakwa, E.O.; Sakyi-Dawson, E.; Budu, A.S.Response surface methodology was used to study the effect of extruder characteristics on product quality of rice-groundnut-cowpea extrudates using a single-screw extruder. The combined effect of cowpea (0-20%), groundnut (0-10%) and feed moisture (12.02-44.06%) were used to formulate the products. Product moisture, protein, fat, ash, bulk density, expansion ratio, water absorption capacity (WAC) and swelling capacity were determined. Well-expanded rice-legume blend extrudates of less bulk density and lower moisture content were produced at low feed moisture. Addition of legumes resulted in significant increases in protein, fat and ash contents of the rice-legume extrudates while increasing cowpea increased all the physico-functional properties. The models developed gave R 2 values ranging from 64.01% (WAC at 70C) to 86.5% (bulk density) and suggested that the optimal process variables of low feed moisture (10-12%), cowpea level (20%) and groundnut level (10%) would produce ready-to-eat puffed snack with enhanced nutritive value and physico-functional properties from rice-groundnut-cowpea blend extrudates. © 2011 Wiley Periodicals, Inc.Item Extrusion of Cereal Based-Legume Blend: Process and Product Characteristics(University of Ghana, 2002-10) Asare, E.K.; Sefa-Dedeh, S.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Nutrition and Food ScienceThe evolution of extrusion into cereal processing has widened the available assortment of puffed snack foods and ready-to-eat (RTE) breakfast cereal formulations. In producing these nutritious products, cereals can be fortified with pulse proteins, as these legumes are important sources of food proteins and other nutrients. Response Surface Methodology (RSM) was used in investigating the effects of 3 process variables (viz. Cowpea level, groundnut level and feed moisture) on product indices o f extruded rice-cowpea-groundnut and sorghum-cowpea-groundnut blend systems in a modified oil-expeller. The use of the RSM helped in relating product indices by regression equations to describe the interrelations between the input parameters and the product indices. A Central Composite Rotatable design for K=3 examined the combined effect of groundnut (0 - 10%), cowpea (0 - 20%) and feed moisture(14 - 48.01% for rice blends; 12 - 44.06% for sorghum blend) on product indices such as product moisture, expansion ratio, bulk density, protein , fat, ash (minerals content- calcium, iron and phosphorus), crude fibre, water absorption capacity (at both 27°C and 70°C), swelling capacity, and psychrometric colour terms (L,a,b). The extrusion process was carried out at 165°C. Statistical analysis, development of models and response surface plots were performed using Statgraphics statistical package (STSC, version 4.1). The models developed from the data was used to predict some product indices such as product’s moisture, expansion ratio, bulk density, protein, fat, swelling capacity, water absorption capacity, swelling capacity and the psychrometric colour terms (of L ,a, b) of both rice and sorghum extrudates. Their R2 values ranged between 52.03% - 86.49% and 42.43% - 87.83% for rice and sorghum systems respectively. Lack o f fit test showed no significance hence models developed adequately fitted the data. The physical indices of rice and sorghum blend extrudates such as the moisture content (which ranged between 8.43% - 13.67% and 7.90% - 10. 64% for rice blend and sorghum blend respectively), expansion ratio and bulk density, were affected by feed moisture and cowpea levels. Lower levels o f feed moisture and cowpea addition resulted in good expansion, less bulk density and lower extrudate moisture content in both types of blend at the maximum concentration of groundnut (10%). Increasing the levels of cowpea and groundnut also resulted in increasing levels of the protein (15.76% 19.54% for rice blend and 16.18% - 21.24% for sorghum blend); fat (0.76% - 4.52% for rice blend and 2.22% - 5.97% for sorghum blend); crude fibre (0.694% 1.5% for rice blend and 2.264 - 3.568% for sorghum blend); and ash (0.83% - 1.30% for rice blend and 2.03% 3.66% for sorghum blend; thus increased contents of minerals elements such as calcium, iron and phosphorus). The most remarkable observation was the protein content which increased by as much as between 53.81% - 62.74% and 37.58% - 52.45% in the rice-blend and sorghum-blend extrudates respectively when compared to the extrudates from only the cereals. The water absorption capacity and swelling capacity of flours from both blends were most affected by the feed moisture level. Increasing cowpea addition only caused a slight increase and decrease in the water absorption capacity and swelling capacity respectively. The increasing addition of cowpea increased the brightness or lightness of sorghum blend extrudates and the overall (total) colour change; but decreased both the redness and yellowness of sorghum bend extrudates. However, increasing groundnut addition increased the redness and decreased the yellowness in rice blend extrudates. In the end the models developed, showed that extrusion condition optimal to produce puffed or direct expanded extrudates with spongy structure should be at low feed moisture. Thus low feed moisture together with increasing cowpea(up to 20%) and groundnut(up to 10%) likely to produce ready-to-eat puffed snack with enhanced nutrition from ricecowpea- groundnut and sorghum-cowpea-groundnut blend extrudates (as shown in Figs. 3 -12.Item Modelling the Effects of Feed Moisture and Ingredient Variations on the Physical Properties and Functional Characteristics of Extruded Sorghum- Groundnut –Cowpea Blends using Response Surface Methodology(International Journal Food Engineering 6(4): DOI: 10.2202/1556-3758.1974, 2010) Asare, E.K.; Sefa-Dedeh, S.; Afoakwa, E.O.; Sakyi- Dawson, E.; Budu, A.S.Central composite rotatable design for k = 3 was used to study the combined effect of feed moisture (12-44%), cowpea concentration (0-20%) and groundnut concentration (0-10%) on the physical and functional properties of extruded sorghum-legume blends in a single screw extruder using response surface methodology. Product expansion ratio, bulk density, total colour change, water absorption capacities at 27°C and 90°C and swelling capacities were determined on the products using standard analytical methods. Expansion ratio, bulk density and total colour of extrudates from the sorghum-legume blends decreased with increasing feed moisture. Increasing the concentration of legumes in the product increased the water absorption capacities at 27°C and 70°C and increased swelling capacities due to the gel forming ability of the macromolecules (proteins and starch) in the products and availability of hydrophilic groups to bind water molecules, thus enhancing the functional properties of the blends. Models developed for the indices gave R2-values ranging from 61.6% (for water absorption capacity at 27°C) to 89.9% (for bulk density) with insignificant lack of fits indicating the adequacy of the model in explaining the data. The optimal conditions noted for producing the puffed extruded snack products with better physical properties and functional characteristics from sorghum-groundnut-cowpea blends were at 16-18% feed moisture, 14-16% cowpea and 6-8% groundnut additions.Item Response Surface Methodology for Studying the Effects of Feed Moisture and Ingredient Variations on the Chemical Composition and Appearance of Extruded Sorghum-Groundnut-Cowpea Blends(International Journal Food Engineering 6(6), 2010) Asare, E.K.; Sefa-Dedeh, S.; Afoakwa, E.O.; Sakyi- Dawson, E.; Budu, A.S.Studies were conducted to evaluate the effects of feed moisture and ingredient variations on the chemical composition and appearance of extruded sorghum-groundnut-cowpea blends using response surface methodology. Central composite rotatable design for k = 3 was used to study the combined effect of feed moisture (12 to 44 percent), groundnut concentration (zero to 10 percent) and cowpea level (zero to 20 percent) on the chemical composition and appearance of extruded ready-to-eat sorghum-legume blends in a single screw extruder. Product moisture, crude protein, crude fat, ash (minerals), crude fibre, carbohydrate and colour (L, a and b-values) were determined on the products using standard analytical methods. The results showed that irrespective of the feed moisture level, the extrusion process could reduce the product moisture to levels between six to 10 percent and low enough to extend the shelf life of the derived products. Increasing additions of cowpea and groundnut resulted in significant increases in protein, fat and ash (minerals - calcium, iron, and phosphorus) contents of the sorghum-legume extrudates. Increasing addition of cowpea decreased the redness of the sorghum extrudates, while no changes were noted with groundnut additions. Contrary, increasing groundnut addition generally increased the yellowness at all cowpea concentrations, while only minimal changes were noted with cowpea additions. The lightness of the sorghum extrudates decreased with increasing cowpea and groundnut concentrations, and this was more pronounced at higher cowpea concentrations and with increasing groundnut levels. The level of feed moisture showed no effect. Models developed for the indices gave R2-values ranging from 67.04 percent (for a-value) to 87.83 percent (for fat content), with insignificant lack of fits indicating the adequacy of the model in explaining the data. The optimal conditions likely to produce ready-to-eat puffed snack with enhanced nutritive value and appearance from sorghum-groundnut-cowpea blend extrudates was at low feed moisture (10 to 14 percent), cowpea level (18 to 20 percent) and groundnut level (six to eight percent).Item Survival of Mushrooms and Termites Upon Pesticide Exposure in the Cocoa Agro-ecosystem(JOURNAL OF TROPICAL LIFE SCIENCE, 2023) Asare, E.K.; Avicor, S.W.; Bukari, Y.; Amoako-Attah, I.; Agyare, S.; Yeboah, M.; Wiafe-Kwagyan, M.Pesticides have become integral parts of cocoa cultivation for the management of in sect pests and fungal pathogens which cause significant damage to the crop. However, continuous pesticide usage in the cocoa agro-ecosystem is of concern due to perceived adverse effects on non-target organisms. In this study, mushrooms and associated ter mites were used to elucidate the possible effect of fungicides and insecticides on non target organisms in the cocoa agro-ecosystem. The vegetative phase of Pleurotus sa jor-caju (Oyster mushroom), Volvariella volvacea (Paddy straw mushroom), Termi tomyces globulus, and Termitomyces robustus (Termite mushrooms) were subjected to concentrations of commercially formulated fungicides (metalaxyl 12 % + copper (I) oxide 60 % and cupric hydroxide 77 %) and insecticides (imidacloprid 20 % and bifenthrin 2.7 %) to observe their growth rates on Potato Dextrose Agar (PDA). Worker termites, Macrotermes bellicosus, were also exposed to the pesticides in Petri dishes for 24 h to observe their mortality. The manufacturer’s recommended concen tration of 245 ppm for bifenthrin completely inhibited mycelial growth of all the mushrooms and caused 100% mortality of termites. At 0.0245 ppm, the insecticide caused 60% mortality of termites, but it had no inhibitory effect on the mushrooms. Except for P. sajor-caju, mycelial growth of all the other mushrooms was completely inhibited by metalaxyl + copper (I) oxide at the manufacturer’s recommended con centration of 2400 ppm. However, mycelial growth rate of the mushrooms at 0.24 ppm of the fungicide was similar to the control plates. Although the recommended concentrations of the pesticides inhibited mushroom activity under controlled condi tions, mushroom survival in the cocoa agro-ecosystem amidst pesticides could be due to diluted pesticide concentrations that result in the soil after application which is usu ally directed at the pods, trunk, and foliage