Agnes Simpson Budu

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

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).

Effect of 1-methylcyclopropene on the quality of minimally processed pineapple fruit

Rapid deterioration is a problem with minimally processed pineapple fruit. Effects of 1-methylcyclopropene treatment with or without ascorbic acid treatment on respiration rate, browning and other quality parameters were investigated for minimally processed fruit stored at 4.5degreesC for 12 days in air. 1-methylcyclopropene treatment reduced respiration rate and browning, and maintained more acceptable visual quality in pineapple fruit slices. 1-methylcyclopropene-treated pineapple fruit slices reached an unacceptable visual quality level after day 8. In contrast, untreated slices were unacceptable after 4 days storage. Respiration rate was reduced from about 5.8 mL CO2/kg.h in control fruit to about 4.8-5.0 mL CO2/kg.h in 1-methylcyclopropene- treated fruit at 12 days. Lightness of control pineapple slices reduced from L* 77 to 65 over 12 days, while 1-methylcyclopropene- treated fruits remained at about L* 72. 1-methylcyclopropene treatment increased electrolyte leakage from pineapple slices. Apart from further suppression of respiration rate, there was no benefit of using 1-methylcyclopropene at above 1.0 muL/L. 1-methylcyclopropene treatment reduced ascorbic acid loss from 44% for untreated fruit to 29% for 1-methylcyclopropene- treated fruit at the end of the 12-day storage. An additive effect of 1-methylcyclopropene treatment was recorded for pineapple fruit slices dipped in 2% (w/v) ascorbic acid solution for 3 min. Ascorbic acid treatment resulted in reduced browning, electrolyte leakage and fruit softening. Therefore, 1-methylcyclopropene treatment helps maintain the quality of minimally processed pineapple fruit at least partially by reducing the hydrolysis of endogenous ascorbic acid.

Effect of pulp preconditioning on acidification, proteolysis, sugars and free fatty acids concentration during fermentation of cocoa (Theobroma cacao) beans.

Changes in acidification, proteolysis, sugars and free fatty acids (FFAs) concentrations of Ghanaian cocoa beans as affected by pulp preconditioning (pod storage or PS) and fermentation were investigated. Non-volatile acidity, pH, proteolysis, sugars (total, reducing and non-reducing) and FFAs concentrations were analysed using standard methods. Increasing PS consistently decreased the non-volatile acidity with concomitant increase in pH during fermentation of the beans. Fermentation decreased the pH of the unstored beans from 6.7 to 4.9 within the first 4 days and then increased slightly again to 5.3 by the sixth day. Protein, total sugars and non-reducing sugars decreased significantly (p < 0.05) during fermentation, whereas reducing sugars and FFA increased. PS increased the FFA levels, reduced the protein content but did not have any effect on the sugars. The rate of total and non-reducing sugars degeneration with concomitant generation of reducing sugars in the cocoa beans was largely affected by fermentation than by PS.

Microstructural and Physico-Functional Characterization of Starches from Selected Cowpea (Vigna unguiculata L. Walp.) Varieties Developed for Pest and Disease Resistance

The microstructure, physico-chemical and functional properties of legume starches affect their cooking quality as well as the texture and rheological behaviour of foods processed from them. Thus, this study sought to establish the microstructural, physico-chemical and functional properties of the native starches of four cowpea varieties - Bengpla, Asetenapa, Asontem and CR-06-07, that have been developed against disease and pest infestation. The starches were extracted from the cowpeas and their gelation capacity, pasting characteristics, solubility, swelling volume and swelling power were studied using standard analytical methods. Microstructures of the starches were examined using light microscopy. Isolated starch granules from the microstructural examination showed irregular shapes with predominance of spheroid and oval forms in varying sizes. Starch granule sizes ranged from 1.9 mm in Asetenapa to 2.9 mm in Asontem. Swelling power, solubility and swelling volume at 95°C was highest in Bengpla with Asetenapa recording the lowest. However Asontem had the highest value in terms of solubility. With the exception of gelation capacity, significant differences (P ? 0.05) were observed in all the studied parameters amongst the different cowpea varieties. Thus, the cowpea starches showed wide variations in microstructure, physico-chemical and functional properties among the studied varieties and these could be used in the selection of the varieties for specific food processing applications.

Response surface methodology for studying the effect of processing conditions on some nutritional and textural properties of bambara groundnuts (Voandzei subterranea) during canning

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 bambara groundnuts. Increasing the concentration of sodium salt added during soaking caused significant (P≤0.05) decreases in phytates, tannins and the hardness of the seeds, suggesting that pre-canning treatments of blanching, soaking and sodium hexametaphosphate salt addition can be used to effectively reduce the phytates, tannin levels with minimal mineral (ash) loss and enhanced textural integrity of the canned bambara groundnuts.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 bambara groundnuts. Increasing the concentration of sodium salt added during soaking caused significant (P<or=0.05) decreases in phytates, tannins and the hardness of the seeds, suggesting that pre-canning treatments of blanching, soaking and sodium hexametaphosphate salt addition can be used to effectively reduce the phytates, tannin levels with minimal mineral (ash) loss and enhanced textural integrity of the canned bambara groundnuts.

Application of Response Surface Methodology for Optimizing the Pre-processing Conditions of Bambara Groundnut (Voandzei Subterranea) during Canning

Bambara groundnut (Voandzei subterranea) seeds were canned with the objective of investigating the optimal pre-processing conditions that would yield the best quality canned product from it. 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 for k = 3 were used for the canning of the bambara groundnuts 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 surface methodology. Regression models were generated using regression analysis and used for the plotting of response surface curves. Adequacy of the model equation for predicting the optimum responses were tested in the experiment using the blanching time of 2-12 minutes, soaking time of 0-24 hours and salt concentration [(NaPO3)6] of 0-1%. Three optimal processing conditions of the canning procedures of the bambara groundnuts were determined from the mathematical models. The results revealed that the soaking time, blanching time and salt concentration all significantly (p<0.05) influenced most of the quality indices of the canned bambara groundnuts. The optimal conditions required to achieve the optimum moisture content, pH level and other quality indices studied on the canned bambara groundnuts were blanching time of 5 min, soaking time of 12 h and [(NaPO3)6] salt concentration of 0.5 %. These conditions would give the best quality canned product from bambara groundnut with acceptable quality characteristics.

Application of Multivariate Techniques for Characterizing Composition of Starches and Sugars in Six High Yielding CMD Resistant Cassava ( Manihot esculenta Crantz ) Varieties

High yielding and cassava mosaic disease (CMD) resistant cassava varieties have been developed by the Crop Research Institute of Ghana with varying compositions and concentrations of starches and sugars. This study characterized four of these improved cassava varieties (Ampong, Broni bankye, Sika and Otuhia) together with two traditional varieties (Amakuma and Bankye fitaa) for their composition of starches and sugars using principal component and cluster analyses. The concentration of total sugars, reducing and non-reducing sugars, sucrose, starches, amylose and amylopectin were determined using standard analytical methods. Results obtained were total sugar (4.04-18.47%), non-reducing sugar (2.08-16.21%), sucrose (1.98-15.40%), starch (15.39-31.07%) and amylose (30.57-40.33%) and these were significantly different (p < 0.05) amongst the studied cassava varieties. The improved varieties (Ampong, Broni bankye, Sika and Otuhia) had high total sugar levels ranging from 7.19 to 18.47 %. With the exception of Broni bankye (improved variety) all the improved and traditional varieties were high starch and amylose containing varieties. These differences in the biochemical composition of the traditional and improved cassava varieties could be used in their selection for specific food and industrial processing applications.

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

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.

Viscoelastic Properties and Physico-Functional Characterization of Six High Yielding Cassava Mosaic Disease-Resistant Cassava (Manihot Esculenta Crantz) Genotypes

Investigations were conducted to characterize six high yielding cassava mosaic disease (CMD) resistant cassava varieties (Ampong, Broni bankye, Sika, Otuhia, Amakuma and Bankye fitaa) that have been developed by the Crop Research Institute of Ghana in collaboration with the International Institute for Tropical Agriculture for their differences and similarities in viscoelastic properties and physico-functional characteristics. The viscoelastic properties (pasting temperature, peak viscosity, final viscosity, breakdown viscosity and setback viscosity), and physico-functional characteristics (swelling power, solubility and water binding capacity) were determined using standard analytical methods. The results showed wide variations in viscoelastic properties with values ranging from 270.67-380.67 BU for peak viscosity, 37.17-260 BU for final viscosity, 199.83-282.33 BU for breakdown viscosity, 21.83-98.66 BU for setback viscosity and 2.48-10.51 min time to pasting temperature. Similarly, variations in swelling power, solubility and water binding capacity were noted with values ranging between 14.34-17.04%, 73.04-79.98% and 234.53- 276.63% respectively for all the different cassava genotypes. Statistical analysis showed significant differences (P < 0.05) amongst the studied cassava genotypes with Sika (improved variety) having exceptionally high viscoelastic characteristics. The differences noted in the viscoelastic properties and physico-functional characteristics of the six CMD resistant cassava genotypes could be used in their selection for specific food and industrial processing applications.

Knowledge and consumption patterns of coffee creamers in Accra, Ghana

Purpose – Major health benefits have been associated with the consumption of soy based foods. Non‐dairy beverage creamers made from soy protein will reduce cost and appeal to lactose intolerant consumers. The purpose of this study is to determine the knowledge and perceptions of beverage creamers among consumers in Accra, as a case study for many West African countries.Design/methodology/approach – Self‐administered questionnaires were used to evaluate the knowledge and attitudes of beverage consumers to the use of creaming agents.Findings – Chi square tests conducted on data collected during the survey showed no significant association between social status and consumption of beverages such as tea and coffee. Most respondents cream their beverages with dairy milk. They lacked adequate knowledge on non‐dairy creamers but would be prepared to use them if they are proved to be beneficial to human health and well being.Originality/value – Consumer preferences and perceptions of new foods can easily be swayed...