George Amponsah Annor Mr.

Effect of cowpea addition on quality and sensory characteristics of cassava-cowpea composite flour biscuits

George Amponsah Annor et al. — Thu, 14 Jun 2007 11:43:11 PDT

In recent years the use of cassava flour for bakery products other than bread is being promoted though the very low protein content of cassava is of some concern. As a means of increasing the protein content of cassava flour in order to enhance both the nutritional quality and functionality of the cassava flour addition of cowpea flour (a starchy high protein legume) to cassava to formulate a composite flour has been suggested. This study evaluated the quality characteristics of biscuits baked from high quality cassava-cowpea composite flours. Cassava-cowpea composite flours with varying cowpea levels ranging from 30-55% were used to bake biscuits using a modified recipe for cassava biscuits. The protein content, spread factor, texture, biscuit weight and color of the biscuits were measured. Trained panelists evaluated the differences in texture and flavor of the biscuits and sensory acceptability was determined using a consumer sensory panel. Color, hardness and protein content of the biscuits were significantly affected by addition of cowpea flour. Biscuit color progressively darkened as the cowpea flour level increased. Increasing cowpea levels resulted in a reduction of the hardness of the biscuits from 28 N to 16N with substitution of 50% of cassava flour with cowpea flour. Fracturability also reduced from 0.73 to 0.33 mm with addition of 50% cowpea flour. Changes in the spread factor and the biscuit weight were not statistically significant. Protein content of the biscuits increased from 0.6% in the 100% cassava biscuits to 12% in biscuits that had at least 50% cowpea. Flavor scores did not differ significantly among the biscuits samples but texture scores showed a trend from hard to soft which correlated with the instrumental measurements. Biscuits from a composite blend of between 42-51% cowpea were most preferred in terms of texture and flavour. The addition of cowpea flour to cassava flour positively affected the both the nutritional and quality characteristics of the composite flour biscuits. This indicates the feasibility of producing nutritious biscuits with desirable sensory characteristics from cassava-cowpea composite flour.

Effect of Processing Method on the Chemical Composition and Rheological Properties of Flour from Four New Cassava varieties

George Amponsah Annor et al. — Thu, 14 Jun 2007 11:37:48 PDT

Cassava (Manihot esculenta) features prominently in the diets of most West Africans. Traditionally, cassava roots are processed by a variety of methods into many different food products. One of the more recent uses of cassava is to produce flour for baking. There is therefore the need to study the effects of varying processing methods on the chemical composition of cassava have been reported, there is still the need for more studies on cassava flour production. This study investigated the effects of different flour processing methods on the chemical composition and rheological properties of new cassava varieties in order to determine their suitability for various food uses. Three processing methods (grating, slicing and reconstitution of the starch and fiber) were used to obtain the cassava flours from four cassava varieties. The flour samples were analyzed for proximate composition, starch, reducing and non-reducing sugars, free cyanide as HCN, non-glucosidic cyanogens and total cyanogens. Pasting characteristics of the flours were determined using the Brabender viscoamylograph. Both the variety and the method of flour production significantly affected flour chemical composition. The moisture, protein, ash, sugar and fibre contents were lowest in reconstituted flours (RCF) though the starch content of RCF was highest. Cyanogen levels in the flours were also significantly affected by processing methods. Reconstituted flours had lowest cyanogenic potential. The total cyanogens ranged from 0.083 for RCF to 1.838 mg CNequiv/Kg. for flours produced by slicing. Slicing produced flours with the lowest peak paste viscosities (298BU to 456BU) whilst that for RCF were highest (714BU to 914BU). All other rheological indices were also lowest for flours from the method of slicing. The reconstitution method significantly reduced the total cyanogens of the flours but resulted in flours with higher viscosities. The paste viscosities of grated cassava flours however made them more more suitable for baking.

Optimization of the Processing Conditions and Quality Characteristics of Water Melon Jams Using Response Surface Methodology

George Amponsah Annor et al. — Thu, 14 Jun 2007 11:28:13 PDT

Water melon (Citrullus vugaris) is a fruit grown for its thirst quenching property rather than for ant nutritional value. It consists of 92% water and 8% sugar, so it is aptly named. Its high water content makes it impracticable to use this fruit for jam, but because it is seasonal, processing the fruit into jam is a means of keeping this out of season produce available throughout the year. This study sought to investigate the effect of sugar concentration and pH balance on the chemical, physiochemical and physical properties of watermelon jams. Through the response surface methodology (RSM), the effect of refractive index, soluble solids, pH, total acidity, moisture, ash, total carbohydrate, hardness and colour with respect to sugar concentration and pH were determined. Response surface models were generated using regression analysis and used to plot graphs for each of the indices studied. The results revealed that inclusion of 60% sugar improved the soluble solids content, texture, colour and gel set of the jam. Inclusion of sugar concentration above 60% did not increase soluble solids content of the jam and resulted in jams of sticky consistency which is unacceptable from the standpoint of the consumer. The low sugar jams failed to set and had unacceptable texture, colour and soluble solids content. Sugar significantly contributes to the quality of the jam but above 60% sugar concentration, the quality of the jam is not improved. Acid had significant effect on the gel set, texture, total acidity and pH of the finished jam. All the pH levels studied resulted in jams of acceptable pH when analyzed. The optimal conditions required achieving the optimum soluble solids; pH and all other indices studied on the watermelon jam were sugar concentration of 60%, pH 3.0 and 3.5 with pectin concentration of 0.5%.

Microbial quality of Street fruit Juices retailed in

George Amponsah Annor et al. — Thu, 14 Jun 2007 10:53:01 PDT

Cowpea fortification of Tatale: A traditional plantain-based snack food

George Amponsah Annor et al. — Thu, 14 Jun 2007 10:49:14 PDT

Effect of soybean fortification and fermentation techniques on the nutritional composition

George Amponsah Annor et al. — Thu, 14 Jun 2007 10:43:08 PDT

Effects of cowpea fortification and the level of ripeness of plantain on the nutritive value of plantain based snack foods

Ann Nancy Etsey et al. — Thu, 17 May 2007 08:10:06 PDT

To investigate effects of cowpea addition and level of ripeness of plantain on the nutritional and sensory characteristics of Kaklo and Ofam in Ghana, A 2X4 factorial experiment with firm and soft ripe plantain and cowpea fortification of 0, 10, 20 and 30% was designed. The proximate composition and acceptability of products using a 7-point hedonic scale were evaluated. With the addition of 30% cowpea, the protein content of the Kaklo from the firm ripe and soft ripe plantain increased from 2.92% to 7.32% and 3.65% to 8.05% respectively, whilst the protein of the Ofam from the firm and soft ripe plantain also increased from 3.80% to 8.45% and 3.75% to 8.15% respectively. The 10% fortified Kaklo and Ofam were the most acceptable. The cowpea addition significantly affected the nutritional value of the Kaklo and Ofam. To obtain an acceptable cowpea fortified plantain-based snack, the fortification should be done at 10%.

Effect of Sugar, Pectin and Acid Balance on the Quality Characteristics of Pineapple (Ananas Comosus) Jam.

Emmanuel Ohene Afoakwa et al. — Thu, 17 May 2007 08:10:06 PDT

Investigations were conducted on the effects of sugar concentration (0%, 50%, and 100%), pH balance (3.0, 3.2, and 3.5) and high methoxy pectin concentration (0%, 0.5%, and 1.0%) on the chemical, physico-chemical characteristic of pineapple jams using standard analytical methods. Inclusion of 50% sugar was observed to improve the colour of the jam as well as the texture, gel set and solid content. The low calorie jams had unacceptable texture, colour, gel set and total soluble solids content. The jams of this formulation were too soft, and could not hold their form. Addition of 100% sugar concentration did not improve the texture, colour and gel set further but increased the soluble contents to acceptable limits. The addition of lemon juice as a source of acid had an effect on the gel set, texture and finished pH of pineapple jams. The jam samples balanced to pH 3.2 and 3.5 were of acceptable finished pH when analyzed. Jam colour was not greatly affected by the incorporation of lemon juice. Addition of pectin had no significant effect on the pH of the finished jams. Sufficient pectin levels however improved the texture, colour and solids content of pineapple jams. When no pectin was added on the processing, the jam samples were hard, tough and stiff and this was more evident in the 100% sugar jam formulations. When even 0.5% pectin was added, the texture improved greatly and the jam became softer yet firm enhancing spreadability. At 1.0% pectin concentration, spreadability of the jam was poor and colour became redder. It also contributed to reduce soluble solids content in the jam. Sensory rating of the pineapple jams indicated that sugar improves in pineapple jams. When pH was decreased with the incorporation of lemon juice a sour aftertaste in the pineapple jam was reported. Pectin contributes to the spreadability of pineapple jams. Results show that there is a significant difference (p0.5) in the jam formulations as a result of difference in concentrations of sugar, acid and pectin. To establish a good quality jam, a sugar concentration of at least 50%, with the addition of 0.5% pectin would produce a jam of acceptable spreadability and gel set and a pH level of between 3.2 and 3.5 would contribute to a good gel set and excellent taste as well.

Functional properties and sensory characteristics of soy-fortifed gari.

Emmanuel Ohene Afoakwa et al. — Thu, 17 May 2007 08:10:06 PDT

A major drawback of gari is that, it is basically a carbohydrate meal and thus low in nutritional quality if consumed alone. Despite its inherent nutritional drawbacks, the product is reported to have interesting functional characteristics. The objective of this study was to study the functional and sensory characteristics of soybean fortified gari. A 3X4 factorial experimental design was used. The principal factors investigated were fermentation time (0, 24 and 48hours) and soybean concentrations (0%, 10%, 20%, and 30%).Swelling and water absorption capacities at 27°C and 70°C, swelling power and solubility were measured. Ten (10) trained panellists were asked to rank the samples for their colour, flavour, mouth feel texture and overall acceptability using a 7-point hedonic scale. ANOVA was conducted on the results at p<0.05.Swelling capacity generally increased with increase in fermentation time, but decreased slightly with increasing soybean concentration. Increase in fermentation time and soybean concentration, significantly increased the water absorption capacities at 27°C and 70°C.Comparative evaluation of the swelling power an solubility of all the samples revealed that the unfortified sample fermented for 48 hours had the least solubility (30.4%) and the highest swelling power (11.2), whilst the 30% fortified which is not fermented had the highest solubility (43.7%) and the least swelling power (6.1). The texture, flavour and mouth feel of the 10% fortified gari was the most preferred. The functional characteristics were significantly affected by the increases in fermentation time and soybean concentration. The colour of the unfortified product was the most preferred.

Optimization of the Processing Conditions and Quality Characteristics of Water Melon Jams Using Response Surface Methodology.

Emmanuel Ohene Afoakwa et al. — Thu, 17 May 2007 08:10:05 PDT

Influence of cowpea addition on the nutritional, functional and rheological properties of unripe plantain flour.

Esther Sakyi-Dawson et al. — Thu, 17 May 2007 08:10:05 PDT

Cowpea fortification has been used to effectively improve the protein content of some traditional foods. The objective of this work was to investigate the effects of cowpea fortification on the nutritional, functional and rheological characteristics of unripe plantain flour. Fortification levels of 10% and 20% were used. The cowpea–fortified plantain four was evaluated for its proximate composition (moisture, protein, fat, ash and fibre), water absorption and swelling capacities. The rheological properties (pasting temperature, peak viscosity, viscosity at 95°C and 95°C-hold) were also determined. The crude protein of the plantain flour increased from 3.3% to 6.3% with 20% cowpea fortification. Crude fibre, ash and fat all increased with increasing cowpea fortification. The addition of cowpea decreased the water absorption capacities of the flour. The swelling capacity of the flour was generally decreased with an increase in the amount of cowpea. The addition of cowpea increased the pasting temperature of the flour from 63.5°C to 65.5°C, whilst the peak viscosity decreased from 800BU to 570BU with 20% cowpea fortification. Cowpea fortification enhanced the nutritional qualities of the plantain flour and can therefore be considered as an option for improving the nutritional quality of plantain-based products.

Souring and starch behaviour during co-fermentation of cassava and soybean into gari, an African fermented product

Emmanuel Ohene Afoakwa et al. — Thu, 17 May 2007 08:10:04 PDT

Souring of cassava dough during fermentation is an important and desirable quality attribute in the processing of gari. This study aimed at evaluating the some chemical changes that occur as well as the characteristics of starch during the co-fermentation of cassava and soybeans into gari. A 3X4 factorial experimental design was used. The principal factors investigated were fermentation time (0, 24 and 48hours) and soybean concentrations (0%, 10%, 20%, and 30%). Titratable acidity, pH, starch content and its characteristics were evaluated using the Brabender Viscoamylograph. ANOVA at p<0.05 was conducted on the results. pH decreased with increasing fermentation time and soybean concentration. This observation was opposite for titratable acidity. Significant differences (p<0.05) were observed in the pH and titratable acidity as fermentation time increased. Increased soybeans concentration did not have significant effects on the pH and titratable acidity. The starch content significantly decreased with increasing fermentation time and soybean concentration. It decreased from 69.8% to 60.4% after 48hours of fermentation of the unfortified sample. Pasting temperature significantly increased with increase in fermentation time and soybean concentration. Viscosity at 95°C and at 50°C HOLD decreased with increasing fermentation time and soybean concentration. Peak viscosity decreased from 1150BU to 820BU and 750 after 48 hours of fermentation and 30% soybean fortification respectively. Souring was not significantly affected by co-fermentation of cassava and soybeans. The co-fermentation of cassava and soybeans had significant effects on the pasting temperature, peak viscosity and viscosity at 95°C HOLD.

Influence of Cowpea Addition and Dehydration Technique on the Nutritive Value and Rheological Properties of Maize-based Traditional Foods

Emmanuel Ohene Afoakwa et al. — Thu, 17 May 2007 08:10:04 PDT

Fortification of cereal-based traditional foods with legume protein can improve their nutritional value. The objective of this work was to find out the extent to which the addition of cowpea affects the desirable quality characteristics of traditional foods prepared from fermented maize and also to assess the effect of dehydration technique on the nutritive value, physico-chemical, functional and rheological properties of the products. A 3 x 2 x 4 factorial experiment with cowpea level, dehydration method and storage time as the respective variables was done. Two different modified traditional foods namely Oven-dried fermented maize flour and Solar-dried fermented maize flour were processed. Proximate analysis (moisture, protein, fat, ash, fibre and carbohydrate), pH, titratable acidity, fat acidity and rheological properties (pasting temperature, peak viscosity, viscosity at 95°C and 95°C-hold, and viscosity at 50°C and 50°C-hold) were evaluated using standard analytical methods. Cowpea addition caused only minimal changes in the proximate composition with the exception of protein content, which increased remarkably from 10.5 to 14.3%, 10.7 to 14.4% and 10.4 to 14.7% with 20% cowpea addition respectively for the solar-dried and oven-dried products. The dehydration techniques used caused no remarkable changes in the proximate and chemical composition of the products. The product pH and fat acidity increased with concomitant decreases in titratable acidity with increasing cowpea addition. The cowpea level and dehydration method resulted in comparable rheological properties with pasting temperatures ranging from 72.6 to 73.6 °C, peak viscosities between 2620 and 2780 BU and viscosities at 50 °C between 2400 and 2720 BU for both the oven-dried and solar-dried fermented maize flours. The application of cowpea fortification and dehydration to traditional foods suggests a viable option of promoting the nutritional qualities of African maize-based traditional foods with acceptable rheological and cooking qualities.

Effects of cowpea fortification and the level of ripeness of plantain on the nutritive value of plantain based snack foods in Ghana.

Esther Sakyi-Dawson et al. — Thu, 17 May 2007 08:10:03 PDT

Cowpea may be used as a fortifying agent because it’s high protein level and its consumption by a large population. To investigate the influence of the addition of cowpea and the level of ripeness of plantain on the nutritional and sensory characteristics of Kaklo and Ofam which are popular plantain snacks in Ghana, A 2X4 factorial experiment with firm and soft ripe plantain and cowpea fortification of 10%, 20% and 30% was designed. The proximate composition (moisture, protein, fat, ash and fibre), total sugars and starch contents were determined. The acceptability of the products was also determined using a 7-point hedonic scale. All the proximate indices increased with an increment in cowpea concentration. The protein content of the products increased from 2.9% to 7.3% with 30% cowpea fortification. Ripening increased the moisture and sugar contents of the product but decreased the fibre and starch contents. The starch content was decreased from 17% to 9% with ripening. Sensory evaluation of the products indicated that there were significant differences (p<0.05) in the sweetness and softness of the 10% and 20% cowpea-fortified soft ripe plantain Kaklo. A significant difference was also found in the softness of the 10% and 20% cowpea-fortified soft ripe Ofam. The 10% fortified Kaklo and Ofam were more acceptable compared to the rest. The addition of the cowpea improved the nutritional value of the Kaklo and Ofam. Cowpea fortification can therefore be used in improving the nutritional content of plantain-based snacks.

Mycotoxin contamination in fermented foods: The present situation in West Africa

George Annor et al. — Thu, 17 May 2007 08:10:02 PDT

Mycotoxins are toxic secondary metabolites produced by fungi that contaminate a wide variety of foods and feeds. Maize, which is a staple food in most West African countries, is an excellent source of mycotoxin contamination. The consumption of mycotoxins has often resulted in serious health problems such as bleeding from the lungs, incoordination, changes in reproductive cycles and infertility. Due to the heavy dietary exposure to food borne mycotoxins in the West African sub-region, substantial research has been conducted to curtail the adverse health effects posed by mycotoxins. This review therefore presents some of the acute and toxic effects of some mycotoxins (aflatoxins, fuminosins and ochratoxin A) produced in some West African fermented foods. Some of the current methods being used to control these mycotoxin contaminations in these foods will also be elaborated.