Advances in Crop Science and Technology
Open Access

Composite flour; Protein; Bread; Sensory; Nutritional content

Introduction

Wheat-based bakery products are widely consumed in the world and in Africa in particular. However, only very few Sub-Saharan African countries cultivate can grow wheat due to unfavourable climatic conditions (Tadesse et al., 2018). Among the wheat-based foods, bread is a major food product, which has gained wide acceptance among consumers in the world (Badifu et al., 2005) [1]. Supplementation of cereal-based foods with other protein sources such as legumes has gained considerable attentions in the recent time (Olapade & Oluwole, 2013). Complementary to cereals, pulses constitute a significant source of dietary proteins with an excellent essential amino acid profile. They are also rich source of minerals especially magnesium, potassium, zinc, and possibly iron (Boye et al., 2010). Cowpeas (Vigna unguiculata), are among legume crops used as dried seeds and forage pods. They are annual dual-purpose legume that grows in the semi-arid tropics covering Africa, Asia, Central and South America, being a valuable component of human food and livestock fodder (Singh et al., 2003) [2]. Cowpeas are an essential dietary component for humans due to their high protein and carbohydrate amounts, relatively low-fat content, and a complementary amino acid pattern to that of cereal grains. As part of a 2000 kcal diet, 100 g of cowpeas supplies 57% and over 150% of the daily requirement for thiamin and folate, respectively. It is an extremely good source of these nutrients. In a similar vein, cowpeas are abundant in a few minerals. For instance, 100 g of cowpeas provide 41–76% of magnesium, iron, copper, manganese, and phosphorus (Affrifah et al., 2022). Recent studies and consumer interest in cowpeas from across the world have increased because of their demonstrated health benefits, which include anti-inflammatory, anti-cancer, anti-hyperlipidemic, anti-diabetic, and anti-hypertensive qualities (Jayathilake et al., 2018). Even though Ethiopia has little experience creating recipes with cowpeas, many different cuisines have previously been created and enjoyed in other African nations. The most often consumed cowpea-based foods have reportedly been identified as Ata (doughnut), Abobo (stew), and Atassi (mixed dish of cowpeas and rice) in Benin (Akissoé et al., 2023) [3].

Several scientific reports have indicated enrichment of wheat flour for baking; including addition of fluted pumpkin flour is important to enhance nutritional values of foods (Giami et el., 2003). Bread making potential of cowpea flour incorporated in soft wheat flour has been investigated (Ahmed & Campbell, 2012; Olapade & Oluwole, 2013). Despite their nutritional and economic importance, cowpeas are underutilized legumes in Ethiopia. In addition, it has been received relatively little attention from a research standpoint. Carbohydrate source foods are staples in the Ethiopia and animal origin proteins are out of reach of many households. Besides, Ethiopian traditional bread and other bakery products are solely prepared from wheat flours. There is a necessity to incorporate nutrient rich legumes in traditional diet to enhance their utilization and improve nutritional quality of foods. Developing nutrient dense, affordable and accessible food products from locally produced ingredients is a viable and sustainable approach diversify diet as well as to address the problem of malnutrition. Thus, this research was conducted to develop cowpea-based traditional bread to diversify diet and alleviate the problem of malnutrition specially protein malnutrition in the country [4].

Materials and Methods

Ingredient collection and preparation.

Ingredient collection and preparation

The grains of bread wheat variety Shorima were collected from Kulumsa Agricultural Research Center. Similarly, cowpea variety Bole was Melkassa Agricultural Research Center. The cowpea seeds were soaked overnight and dried. Both the grains of wheat and cowpea were milled into flour using cyclone sample mill (Model: 3010-019).

Composite flours (wheat and cowpea) formulations

The wheat and cowpea flours were formulated using design expert 14. Table 1 presents actual proportions of the flours. The Cowpea substituted instead of wheat flours and evaluated in comparison with 100% wheat (control) (Table 1).

Table 1: Formulations of the composite flours.

Nutritional compositions of the composites

The methods developed by Association of Official Analytical Chemists (AOAC, 2010) were used to determine crude protein, crude fat, crude fiber, moisture and ash contents the composites (wheat and cowpea) and bread samples. Total carbohydrate was estimated by difference method [5].

Mineral content analysis

For mineral content analysis, the samples were prepared using dry ash as described by Jones et al. (1990). Atomic Absorption Spectrophotometer determined minerals including calcium, magnesium, sodium, potassium, iron, zinc, copper and manganese [6].

Functional properties

Bulk density, Water Absorption Capacity, water solubility index and Dispersibility of the composite flours were determined using standard methods (Abiodun et al., 2014) [7].

Bulk density of the flour

Bulk density was determined based on the methods used by (Narasinga, 1984). A mass of 50 g of the sample was put in to a 100 ml measuring cylinder. The cylinder was tapped on a laboratory bench continuously until a constant volume was obtained. Then, the volume of sample was recorded. The bulk density was calculated as weight of the ground flour (g) divided by its volume (cm3) [8].

Water absorption capacity (WAC)

WAC was determined with the method reported by Sosulski (1962) as cited by Ayinadis et al. (2010). 25 ml of distilled water is added to a sample of 3g composite flour (w1) in a weighed centrifuge tube (w2) and stirred six times for 1 min at 10 min intervals. The mixtures were centrifuged at 3000 rpm for 25 min and the clear supernatant was decanted and discarded. Pellets were dried at 50oC for 25 min. The adhering drops of water were removed and then reweighed (w3). The amount of water retained in the sample was recorded as weight gain and was taken as water absorbed. Water absorption capacity was expressed as the weight of water bound by 100 g dried flour [9].

Dispersibility

Dispersibility was determined by the method of Kulkarni (Kulkarni et al.,1991). 10 g of flour sample was weighed into a 100 ml-measuring cylinder. Distilled water was added up to 100 ml volume. The sample was vigorously stirred and allowed to settle for 3 h. The volume of settled particles were recorded and subtracted from 100 to give a difference that was taken as percentage dispersibility. Solubility index was determined by the method of Kusumayani (Kusumayanti et al.,, 2015).

Statistical analysis

All the means of duplicate samples for the proximate composition and sensory properties of the bread were calculated. The data obtained was then subjected to Analysis of variance (ANOVA), where significance difference existed; LSD test was employed in separating the means [10].

Result and Discussion

Nutritional compositions of composite flours

The nutritional compositions of wheat and cowpea composite flours are presented in Table 2. The result of the study reveals that except for fiber contents, which were not significant; all the formulations were found to be significantly different (P < 0.05) [11]. This study suggested that 75% wheat- 25% cowpea was found to be an optimum blend for the improved total mineral content following the control. Protein and ash contents of the composites increased with an increasing level of cowpea flour, which might be due to the high protein and mineral contents of legumes in nature. The highest protein and ash contents were recorded for formulations containing 50% cowpea flour. In line with this, Nanyen et al. (2016) have reported protein value of 17.5% in a flour blend of 50% wheat, 20% acha and 30% mung bean. It has been reported that incorporating 5% cowpea in wheat based bread resulted 16% increment in protein content (Oladunmoye et al., 2010) [12]. The highest carbohydrate content was recorded in 100% wheat sample that might be due to the starchy nature of cereals in general and that of wheat in particular. Though not high in other parameters, the 62.5% Wheat: 37.5% Cowpea had highest carbohydrate and caloric value than the rest of the treatments [13]. The nutritional improvement of bread by incorporating legumes flour has been highlighted by previous findings (Rashwan & Hefny, 2020). The influence of incorporation of cowpea flours on nutritional compositions of the composite flour was observed to be positive. The protein value of the composites increased with an increasing substitution of Wheat flour by cowpea flour. This could be attributed to the high protein content of cowpea Moisture content of the composite flours was in the range between 7.3 and 9.8%, indicating longer storage (Table 2).

Table 2: Nutritional compositions of wheat-cowpea composite flours.

Mineral contents of composite flours

Table 3 presents the mineral compositions of wheat and cowpea composite flours. The result showed that all minerals evaluated in this study were significantly different for each proportion (P < 0.05) except Calcium. These composite flours' mineral content is a major factor in defining their nutritional worth and possible health advantages (Noorfarahzilah et al., 2014) [14]. The current result showed that iron content of all the treatments was lower than the control. It indicates that there is not improvement on iron content of flours by cowpea incorporation. However, the previous study highlights the cowpea improves overall mineral composition of composite flours (Feyera, 2020). While the Zinc content was in range of 21.82 mg/kg-23.85mg/kg, the control sample treatment3 and 4 had the lowest and highest value respectively [15]. The composite flour of 87.5% Wheat: 12.5% Cow pea was found to be an optimum formulation for enhancing the zinc content. Similar results have been reported in previous study suggested that substitution of cowpea in cereal based foods for improving nutritional value (Singh, 2020). The highest and lowest Cu value of 5.53mg/kg and 453mg/kg obtained in 87.5W:12.5CP and 100W flour respectively. Though the increment of mineral content was not in the regular order, incorporation of cowpea in the traditional flat bread positively affected the level of essential minerals including Fe and Zn (Table 3) [16].

Table 3: Mineral compositions of wheat-cowpea flour (mg/kg).

Functional properties of the composite flours

The bulk density value of the Wheat-cowpea composite flours was not significantly different (P<0.05) except in 50W:50%CP and 62.5W:37.5%CP. The highest and lowest bulk density value of 0.931% obtained in 50W:50CP flour and the lowest value of 0.794% obtained in 100%W and 87.5W:12.5CP flours. Bulk density value of was found to be high in the sample contained high level of cowpea. According to Okoye (2008), bulk density ranged from 0.94-0.98% was reported for wheat-kidney bean composite flours. This is not in agreement with the current finding which may be attributed to the difference in particle size and density of the flours. Bulk density is vital in determining packaging requirement and material handling [17]. Water absorption capacity of 87.5W:12.5CP and 75W:25CP blends were significantly different among the treatments (p<0.05). Water absorption capacity of the flour was ranged from 117.87 to 145.570% [18]. The WAC value of control sample was found to be lowest as compared to other blends. Cowpea provide more protein than wheat, and the proteins are able to draw in and bind water molecules because of their hydrophilic characteristics. As a result, bean flours with greater protein contents may be better able to absorb water. The ability of flours to absorb water is indicated by their water absorption capacity (Awuchi et al., 2019). WAC is crucial for baking since it influences the end product's texture, moisture levels, and dough consistency. A flour with a higher water absorption capacity may be able to retain more water, improving hydration and perhaps producing baked items that are softer and moister. Similar result was reported in previous studies. According to Akubor & Ukwuru (2004), the wheat-cowpea flour (50%:50%) has a water absorption capacity of 86.0% [19].

The water solubility of the blends was significantly different (p<0.05) except in treatment 3 and 4. The highest and lowest value of WS of 14.903% and 6.765% was obtained in 50W:50CP and 100%W flours respectively. Water solubility value was increased with an increasing level of cowpea in the composites. The water solubility of wheat-legumes-flours can vary depending on the specific type of legume flour added to the mixture. The addition of legume flours to wheat flour can impact the overall water solubility of the dough mixture. Legume proteins are generally less water-soluble than gluten proteins found in wheat (Arbab et al., 2023). The dispensability values of the composites were significantly different (p<0.05) except in the case of 87.5W:12.5CP and 75W:25CP flours which were not differed from each other. The despersibility value of the flour was ranged from 60.233% (62.5W:37.5CP flour) to 73.867% (87.5:12.5CP AND 75W:25CP). Control sample had the dispersibility value of 72.300% (Table 4) [20].

Table 4: Functional properties of wheat and cowpea composite flour.

Sensory evaluation of wheat and cowpea composite flours-based bread

Sensory evaluation of the bread prepared from Wheat and Cowpea composite flours was presented in Table 3. The bread was evaluated for its color, Aroma, Texture, Taste and Overall acceptability. Color is the most important quality parameter which affects consumer and customer preference to foods. The statistical analysis showed that the bread samples were significantly different (P<0.05) in their color. Bread sample 87.5W:12.5CP ranked first by panelists with 4.2857 and followed by Treatment2 with 4.0477, Treatment3 3.9527, Treatment5 3.7143 and Treatment1 3.4290 in terms of color. The aroma, as rated by the panelist showed that Treatment4 and Treatment2 had the highest and lowest value 3.8570 and 3.1907 respectively. The highest (4.000) and lowest (3.0477) value of taste was obtained in 75W:25CP and 62.5W:37.5CP respectively. This study revealed that incoporation of 25% cowpea flour is optimum for a better taste. The lower taste value could be attributed by the beany flour of legumes. It was indicated in previous findings that incorporation of beans in wheat for bread leads to beany flavor (Wang & Jian, 2022). The bread samples were significantly differed (P<0.05) in their overall acceptability. The bread sample 100W had the highest overall acceptability score of 4.00 and followed by sample 50W:50CP, 87.5W:12.5CP, 75W:25CP and 62.5W:37.5CP with respective values of 3.9047, 3.8093, 3.7617, and 3.524. The study conducted by Oladunmoye et al. (2010) reported that wheat-cassava-cowpea-based bread with acceptable sensory properties was developed with incorporation of 20% cowpea flour (Table 5) [21].

Table 5: Sensory Evaluation of wheat-cowpea bread.

Conclusion

Bread of acceptable quality was prepared from composite flours of Wheat and Cowpea & Wheat and mung beans. The bread prepared from Wheat and mung bean composite flours showed the good sensory acceptance. This study showed well accepted bread was prepared from the formulation of 87.5% Wheat: 12.5% Cowpea and the bread prepared from formulation of 87.5%wheat: 12.5% mung beans as compared to other bread samples. It was found that the incorporation of mung bean flour with wheat flour contributed to the increment in nutritional content of the composites. Therefore, the use of cowpea and mung beans in substitution of wheat can enhance utilization of legumes and in turn alleviate problems of malnutrition by avoiding relying on a single crop.

Conflict of Interest

There is no conflict of interest regarding the article.

1. Abiodun OA, Akinoso R, Oluoti OJ (2014) Changes in Functional and Pasting Properties of Trifoliate Yam Flour during Storage. Journal of Applied Sciences and Environmental Management.

Indexed at, Google Scholar, Crossref

2. Affrifah NS, Phillips RD, Saalia FK (2022) Cowpeas: Nutritional profile, processing methods and products-A review. Legume Science 4:1-12.

Indexed at, Google Scholar, Crossref

3. Ahmed MA, Campbell LJ (2012) Evaluation of baking properties and sensory quality of wheat-cowpea flour. World Academy of Science, Engineering and Technology 70: 1221-1223.

Google Scholar

4. Akissoé L, Hemery YM, Madodé YE, Icard-Vernière C, Rochette I, et al. (2023) Current Consumption of Traditional Cowpea-Based Dishes in South Benin Contributes to at Least 30% of the Recommended Intake of Dietary Fibre, Folate, and Magnesium. Nutrients 15(6).

Indexed at, Google Scholar, Crossref

5. Akubor PI, Ukwuru MU (2004) Functional properties and biscuit making potential of. Plant Foods for Human Nutrition, 58: 1-12.

Google Scholar

6. Arbab Sakandar H, Chen Y, Peng C, Chen X, Imran M, et al. (2023) Impact of Fermentation on Antinutritional Factors and Protein Degradation of Legume Seeds: A Review. Food Reviews International, 39: 1227-1249.

Google Scholar

7. Awuchi C, Igwe V, Echeta C (2019) The Functional Properties of Foods and Flours. International Journal of Advanced Academic Research. Sciences 5: 2488-9849.

Google Scholar

8. Boye J, Zare F, Pletch A (2010) Pulse proteins: Processing, characterization, functional properties and applications in food and feed. Food Research International 43: 414-431.

Indexed at, Google Scholar, Crossref

9. Feyera M (2020) Review on some cereal and legume based composite biscuits. International Journal of Agricultural Science and Food Technology 6: 101-109.

Google Scholar

10. Giami SY, Mepba HD, Achinewhu SC (2003) Evaluation of the Nutritional Quality of Breads Prepared from Wheat-Fluted Pumpkin ( Telfairia occidentalis Hook ). 1-8.

Indexed at, Google Scholar, Crossref

11. Jayathilake C, Visvanathan R, Deen A, Bangamuwage R, Jayawardana BC, et al. (2018) COWPEA: AN OVERVIEW ON ITS NUTRITIONAL FACTS AND HEALTH BENEFITS. Journal of the Science of Food and Agriculture 28: 303-325.

Indexed at, Google Scholar, Crossref

12. Kusumayanti H, Handayani NA, Santosa H (2015) ScienceDirect Swelling power and water solubility of cassava and sweet potatoes flour 23: 164-167.

Google Scholar

13. Nanyen D (2016) Nutritional Composition, Physical and Sensory Properties of Cookies from Wheat, Acha and Mung Bean Composite Flours. International Journal of Nutrition and Food Sciences 5: 401.

Google Scholar

14. Narasinga MS (1984) Effect of Partial Proteolysis on the Functional Properties of Winged Bean ( Psophocarpus tetragonolobus ) Flour. 49.

Indexed at, Google Scholar, Crossref

15. Noorfarahzilah M, Lee JS, Sharifudin MS, Mohd Fadzelly AB, Hasmadi M, et al. (2014) Applications of composite flour in development of food products. International Food Research Journal 21: 2061-2074.

Indexed at, Google Scholar, Crossref

16. Oladunmoye OO, Akinoso R, Olapade AA (2010) Evaluation of some physical–chemical properties of wheat, cassava, maize and cowpea flours for bread making. Journal of Food Quality, 33: 693-708.

Google Scholar

17. Olapade AA, Oluwole OB (2013) Bread Making Potential of Composite Flour of Wheat-Acha ( Digitaria exilis staph ) Enriched with Cowpea ( Vigna unguiculata L . walp ) Flour. Nigerian Food Journal 31: 6-12.

Google Scholar

18. Rashwan MRA, Hefny MAH (2020) Wheat-Legumes Composite Flours. 2. Nutritional Value of Bread. Assiut Journal of Agricultural Sciences 51: 33-33.

Google Scholar

19. Singh BB, Ajeigbe HA, Tarawali SA, Fernandez-rivera S, Abubakar M (2003) Improving the production and utilization of cowpea as food and fodder 84:169-177.

Google Scholar

20. Tadesse W, Bishaw Z, Assefa S (2018) Wheat production and breeding in Sub-Saharan Africa climate change 11: 696-715.

Google Scholar

21. Wang Y, Jian C (2022) Sustainable plant-based ingredients as wheat flour substitutes in bread making. Npj Science of Food 6: 1-16.

Indexed at, Google Scholar, Crossref