research article

Quality Assessment of Crackers from the Flour Blends of Wheat, Maize-African Yam Bean Seed and Cassava Cortex

Ebele Christiana Okoye*, Jane Chinyelu Ani, Ugwuanyi, Ginika Ruth and Okaru Chioma Oyeoku

Department of Food Science and Technology, University of Nigeria, Nsukka, Enugu State, Nigeria

*Corresponding author: Ebele Christiana Okoye, Department of Food Science and Technology, University of Nigeria, Nsukka, Enugu State, Nigeria

Received Date: 22 Jan, 2020 ; Accepted Date: 27 Jan, 2020 ; Published Date: 31 Jan, 2020

Abstract

The study explored the potentials of substituting cassava cortex into a composite flour comprising of wheat, maize and African yam bean seed to produce crackers. Flour was produced from maize and African yam bean seed in the ratio 70:30, respectively. The maize-African yam bean seed flour (MAF) composite was blended with wheat flour (WF) at 100: 0, 90: 10, 80: 20, 70: 30 and 60: 40, WF to MAF ratios respectively, and were used to produce crackers samples. The samples were evaluated for sensory evaluation and sample from 70:30 was the most preferred by the panelists based on the overall acceptability. The 70: 30 composites of WF: MAF was further blended with cassava cortex flour at 5, 10, 15 and 20 % while substituting the levels of wheat flour. All the flour samples were then used to produce crackers and analyzed for chemical composition, microbial and sensory qualities. Results showed a significant (p > 0.05) decrease in the protein content (9.33-4.41 %) with an increase in the ash (2.05-2.55 %) and crude fiber (1.55-2.14 %) content of the samples as the inclusion of the level of cassava cortex increased. There was a significant (p < 0.05) increase in the calcium, vitamin but slight increase in the oxalate, cyanide, alkaloid and tannin contents of all the blended samples compare to the control sample (sample WC). No visible bacteria and mould growth were observed in the control sample and the blended samples except for samples CF1 and CF4. The sensory scores showed that sample WC (control sample) had the highest scores among all the samples in terms of flavor, taste, texture, and color, and was also the most preferred by the panelists based on the overall acceptability.

Keywords

African Yam Bean Seeds; Crackers; Cassava Cortex; Flour; Maize; Wheat

Introduction

Biscuits are a ready-to eat, cheap and convenient food products that are consumed among all age groups globally [1,2]. The reasons for such wide popularity are their ready-to-eat nature, affordable cost, good nutritional quality, availability in different flavors and longer shelf-life [3]. The association of wheat consumption with such health problems as the celiac disease makes it pertinent to utilize composite flour in biscuit manufacture, by partial or whole substitution [4]. Consumption of biscuit appears in the list of top ten daily consumed foods, and they are easily available and convenient to be enjoyed as a snack [5].

Attempts were being made in recent days to improve the nutritional qualities and functionality of biscuits, due to competition in the market for more healthy, natural and functional products [6]. Okaka (1999) described the production of biscuits as a mixture of flour and water but may contain fat, sugar/salt, and other ingredients to form a dough which is rested for a period and then passed between rollers to make a sheet. The baked snack products include cookies, crackers, and biscuits. Crackers (also known as savory biscuits) are a versatile thin and crispy food that can appeal to a variety of consumer expectation. They serve as a quick snack with low contents of moisture, sugar, and fat. Due to growing consumer demands for convenience foods, crackers represent one of the fast-growing segments of bakery products (6). Long shelf-good eating quality, and attractive appearance of crackers make their large-scale production and distribution possible [7]. However, wheat is a basic ingredient in crackers and has allow content of essential amino acids like lysine, methionine, and threonine [8]. Also, in recent years, consumers’ concern over potential health problems caused by eating bakery products has grown due to gluten, a protein found in wheat [9]. In many parts of Sub-sahara Africa and most especially Nigeria, advancing prosperity and urbanization coupled with a tremendous increase in population in recent years have led to an increase in the consumption of wheat-based products especially biscuits [10]. Composite flour has the added advantages of improving the nutrient value of bakery products especially when cereals are blended with legumes e.g. African yam bean seeds, bambara groundnut, etc. [11]. Crackers were enriched with African yam bean seeds because it is a high protein which would improve the protein content of the crackers. Maize was added as composite due to the fiber content of maize, which helps to empty to bowl, also good for diabetic and obsessed patients. Also, cassava cortex was added, and it has a higher percentage of crude protein, fat, minerals and crude fiber than the edible part of cassava. However, this was done to assess the quality of crackers made from the flour blends of wheat, Maize-African yam bean seed, and cassava cortex.

Materials

Procurement of Raw Materials

The maize (Zea mays), African yam bean seeds (Sphenostylis stenocarpa), cassava (Manihot esculenta) and other ingredients used in the formulation of the products were obtained from Ogige market in Nsukka, Enugu State.

Sample preparations

Preparation of maize flour

Maize was processed into flour according to the method described by [12]. The maize was cleaned to remove stones, bad grains, dust and other extraneous. The grains were then degermed and dehulled and the hulls discarded. The grains were milled using a hammer mill (Driver Model: De-Demark Super). The particle size of the emerging flour was further reduced by re-milling and sieving (500 μm pore size sieve). Degermed flour produced was packaged in air-tight containers prior to use. The flow diagram to produce the flour is given in Figure 1.

Preparation of African Yam Bean Seed Flour

African yam bean seeds were processed into flour according to the method of Enwere [12]. All the foreign matters and other impurities like stones, dirt, chaff, weevilled seeds and weevils were removed from the seeds and they were washed with clean tap water. The cleaned seeds were soaked in 1 % citric acid for two (2) hours and decorticated. The seeds were sun-dried and milled using a hammer mill (Driver model: De-Demark Super) into flour and sieved (500 μm pore size sieve). The flow diagram to produce African yam bean seed flour is shown in Figure 2.

Production of Cassava Cortex Flour

The corky layers of fresh cassava cortex were scraped off with a knife and the cortex was washed thoroughly in clean water until free from sand and adhering dirt. The cortex was then soaked in water for 4 days (96 hours) with 24 hours change of soak water. After 4 days, the cassava cortex was removed from the water, dried in an oven (Fulton, Model NYC-101 oven) at 50 oC for 24 hours, milled and sieved (500 μm particle size). The flow diagram of the production is shown in Figure 3.

Preparation of Composite Flour from Wheat, Maize, African Yam Bean Seed, And Cassava Cortex

Maize and African yam bean seed flour composite (MAF) were blended in the ratio 70:30. Snack was produced from wheat and graded levels (10, 20, 30, and 40 %) of the composite flour (MAF) and subjected to sensory evaluation in order to identify the most acceptable ratio. The 70:30 crackers sample was the most acceptable among the blended samples based on the overall acceptability as shown in Table 7. However, 70:30 composite of wheat: maize African yam bean seed flour which was selected was further blended with cassava cortex flour. Different levels (5, 10, 15 and 20 %) of cassava cortex flour were used to substitute wheat flour in the most acceptable ratio as shown in Table 1, to produce crackers.

Production of crackers

Each Combination of flours (WC, MC, CF1, CF2, CF3, CF4) from wheat, maize-African yam bean seed and cassava cortex as shown in Table 1 was used in the preparation of crackers.

The crackers were prepared using the recipe described by Pattens [13] with slight modification. Fifty (50) grams of fat was rubbed into two hundred grams of flour from the flour blends already prepared and 2.5 g salt, 20 g sugar, and 1 g baking powder were added. The mixture was blended with 70 ml water to form a firm dough. The dough was manually rolled into sheets (paper thinness) and evenly cut into tiny shapes. The dough cut was arranged on fat greased baking trays and baked in a hot oven 150 ºC for 15 mins and cooled.

Methods

Sample Analyses

Proximate Analysis of the Samples

The moisture (by hot-air oven method), crude fiber, crude protein (Kjeldahl method), fat (Soxhlet extraction) and ash contents of the samples were determined according to the method of AOAC (2010), while the carbohydrate content was determined by difference. Sum of all the proximate components was subtracted from hundred (100). The balance was assumed to be carbohydrat % Carbohydrate = 100 - (% protein, fat, fiber, ash, and moisture).

Determination of Vitamin Contents of the Samples

The photometric method of AOAC [14] was adopted in the determination of vitamin A and Riboflavin (Vitamin B2), the method described by [15] was used in the determination of vitamin E.

Determination of Anti-Nutritional Contents of the Samples

Tannin was estimated by the Folin-Denis colorimetric method described by Kirk RS, Sawyer (15). Phytate was determined using the spectrophotometric method described by Kirk RS, Sawyer (15). Oxalate was determined using the method of Iwuoha and Kalu [16]. The method of Fuleki and Francis [17] was used for the determination of Cyanide. Determination of Alkaloids was done by the alkaline precipitation gravimetric method described by Harbourne [18].

Determination of Mineral Contents of the Samples

Determination of Iron, Calcium, and Phosphorus: The Calcium, Iron and Phosphorus contents of the samples were determined using the method of Atomic Absorption Spectrophotometer (AAnalyst 200, PerkinElmer) as described by Onwuka [19].

Microbial Analysis of the Samples

The total viable count, mould count, and coliform count were carried out on the samples using the Pour-plate method as described by Harrigan WF, McCance [20].

Sensory Evaluation of the Samples

Sensory evaluation of the samples was carried out using a 9-point Hedonic scale as described by Ihekoronye and Ngoddy, [21], with a panel consisting of 30 panelists from the Department of Food Science of Technology, University of Nigeria Nsukka. The nine-point Hedonic scale ranged from extremely like (9) to extremely dislike (1). Samples were presented in identical containers coded with two letters. Each sample was evaluated for flavor, color, taste, texture and overall acceptability.

Experimental Design and Statistical Analysis

The experimental design used in this study was Completely Randomized Design (CRD). The experimental results were analyzed statistically using one-way analysis of variance (ANOVA) using Statistical Product for Service Solutions (SPSS) version 20.

The means were separated using Duncan’s new multiple range test. Statistical significance was accepted at p < 0.05 [22].

 

Results and Discussion

Proximate Composition of Crackers Made from Wheat, Maize-African Yam Bean Seeds, And Cassava Cortex Flours

The result of the proximate composition of the crackers samples is shown in Table 2. There were significant (p < 0.05) differences in the protein content of the samples. The protein content ranged from 4.41 to 9.33 %. The highest value (9.33 %) was observed in sample MC made with 70 % wheat flour and 30% maize-African yam bean seed flour and the lowest protein content (4.41 %) was observed in sample WC (control sample- 100 % wheat flour). This was followed by sample CF4 made with 50 % wheat flour, 30 % maize-African yam bean seed flour and the highest (20 %) cassava cortex incorporation. This shows that the protein content of the samples reduced with increase in the inclusion of cassava cortex flour. Although the protein content was slightly reduced, it was observed that the protein content of the control sample was still lower than that of the blended sample. According to Ubbor and Akobundu [23], the protein content of a cassava-based composite flour can be elevated through the incorporation of legume flours since they are usually carbohydrate dense and very low in protein. The results obtained for protein content (4.41 to 9.33 %) compared well with the results (3.29 to 15.69 %) reported by Owusu et al. [24] for crackers made from cassava and sweet potato flours.

The values for the ash content of the samples ranged from 2.05 to 2.55 %. The highest value was observed in sample CF4 containing 50 % wheat flour, 30% maize-African yam bean seed flour and 20% cassava cortex flour and sample WC had the lowest value. A significant (p < 0.05) difference was observed in the ash content of sample WC when compared to other blended samples. An increase in the ash content of the blended samples was observed, this may be attributed to the incorporation of maize – African yam bean seed flour blends and cassava cortex flour into the product. Thus, increase in the inclusion of maize – African yam bean seed flour blends and cassava cortex flour into the blended samples caused a significant (p < 0.05) increase in the ash content of the samples. The ash content observed in this study compared favorably with the values (0.55 to 2.80 %) reported by Owusu et al. [24] for crackers made from cassava and sweet potatoes flours. Ash content is the total mineral content of products [25].

The crude fiber values obtained ranged from 1.55 to 2.14 %. The crude fiber in the crackers makes them suitable for prevention of constipation. Significant (p < 0.05) differences were observed in the crude fiber of the samples except for samples MC and CF1. The highest value (2.14 %) was observed in sample CF4 which is the sample blended with up to 20 % of cortex flour. Increase in the inclusion of the levels of cortex flour into the blended samples caused a simultaneous increase in the crude fiber content of the blended samples. The crude fiber result obtained was lower than the values (14.1 to 17.1 %) reported by Osundahunsi et al. [26] for cassava fiber as an ingredient in cracker-like products but compared well with the results (2.18 to 2.41 %) reported by Okpala and Okoli [27] for cookies produced from pigeon pea, cocoyam, and sorghum flour blends. Foods with more fiber are important as they help in emptying the bowel by expanding the inside walls of the colon, make an effective anti-constipation, lower cholesterol level in the blood and reduce the risk of various cancers [28].

The moisture content of the samples ranged from 4.85 to 7.45 %. There were significant (p < 0.05) differences among the samples. An increase in the moisture content of the blended samples was observed as the maize-African yam bean seed and cortex flours were added. The moisture content of the control sample (sample WC) was significantly (p < 0.05) lower than the blended samples as shown in Table 16, but blended samples had reasonable moisture contents also that may not affect their keeping quality. At lower moisture content, the deterioration of baked products would be lowered as a result of reduced activity of microorganisms. According to Ezema [29], microbial proliferation was minimum at low moisture content and it confers higher shelf stability of the samples. These values observed compare favorably with the values (6.44 to 7.46 %) reported by Okpala and Okoli [27] and are slightly lower than the values (7.18 to 8.39 %) reported by Agu et al. [30]. Biscuits are generally low moisture foods and this low moisture helps improve the shelf-life of the products.

The fat content of the samples ranged from 17.94 – 19.70 %. There were significant (p < 0.05) differences amongst the samples except for samples WC (control sample) made with 100 % wheat and CF2 made with 60 % wheat flour, 30 % maize-African yam bean seed flour and 10 % cassava cortex flour. The high-fat content observed in the samples can be attributed to some of the raw material used for the product formulation especially fat (shortening) or vegetable oil (which some incorporate during the production of biscuits). The values reported by Owusu et al. [24] for crackers made from cassava and sweet potatoes flours ranged from 10.31 –16.47 % and differed from that obtained in this study. This may be due to the differences in the quantity and the type of fat added or the recipe used.

The carbohydrate content of the samples ranged from 63.30 to 68.46 %. There was a significant (p < 0.05) difference in the carbohydrate content of sample WC (control sample) compared to other blended samples. A gradual decrease in the carbohydrate content of the blended samples was observed as the maize-African yam bean seed and cassava cortex flours were added. This agrees with the findings of Yusufu et al. [31] who reported a decrease in carbohydrate content of cookies when green bean flour was blended with wheat to produce cookies. These values compare favorably with the values (65.08 to 81.28 %) reported by Owusu et al. [24].

Mineral Contents of the Crackers Samples from Wheat Flour and Maize–African Yam Bean Seed Flour Blends and Cassava Cortex Flour

Results of the mineral contents of the samples are shown in Table 3. The iron content of the samples ranged from 0.11 to 0.46 %. There was a significant (p < 0.05) difference in the iron content of sample WC (control sample) compared to other blended samples except for sample CF2 made from 60 % wheat flour, 30 % maize-African yam bean seed flour and 10 % cassava cortex flour. Iron is an essential trace element in human nutrition and its deficiency is a major public health threat worldwide. Iron is an important element in the diet to prevent anemia and other related diseases [32].

The phosphorus content of the samples ranged from 58.89 to 136.80 mg/100g. The highest value of phosphorus was observed in sample CF2 (136 mg/100g) and the lowest value in samples CF3 (58.89 %). There was a significant (p < 0.05) difference in the phosphorus content of the control sample (sample WC) compared to the blended samples.

The calcium content of the samples ranged from 0.02 to 0.10 %. There was no significant (p > 0.05) difference in the calcium content of sample WC (control sample) compared to all other blended samples. Though a slight decrease in the phosphorus content of the blended samples was observed, this may be attributed to the inclusion of the maize-African yam bean seed and cortex flour blends into the samples.

Vitamin content of crackers samples from wheat, maize – African yam bean seed and cassava cortex flour blends

The result of the vitamin contents of the samples is shown in Table 4. The values of vitamin E in the samples ranged from 1.40 to 2.20 %. There was no significant (p > 0.05) difference in the vitamin E content of sample WC (control sample) compared to samples MC, CF1 and CF2, except for samples CF3 and CF4 where significant (p > 0.05) differences were observed. The highest value of vitamin E (2.20 %) was observed in CV (made with 50 % wheat flour, 30 % maize-African yam bean flour and 20 % cassava cortex flour) and the lowest value was in sample WC (control sample). Increase in the level of inclusion of the flour blends, however, caused a slight increase in the vitamin E content of the blended samples.

The vitamin A content of the samples ranged from 129.03 to 580.65 IU. There was a significant (p < 0.05) increase in the vitamin A content of the blended samples when compared with the control sample (sample WC). Thus, there was a significant (p < 0.05) difference in the vitamin A content of sample WC compared to the blended samples. Vitamin A increased significantly (p < 0.05) with an increase in the level of a maize-African yam bean seed and cassava cortex flours added. Increase in the vitamin A content of the product may also be attributed to the inclusion of baking fat which is mandatorily fortified with vitamin A in the dough used in the production of the samples. Vitamin A is critical for vision as an essential component of rhodopsin, a protein that absorbs light in the retinal receptors, it also supports cell growth and differentiation, playing a critical role in the normal formation and maintenance of the heart, lungs, kidneys, and other organs (Ross, 2010).

Vitamin B2 content of the samples ranged from 0.01 to 0.03 mg and there was no significant (p > 0.05) difference among the samples although the increase in the level of addition of the flour blends caused a slight increase in the vitamin B2 content of the blended cracker samples. The values (0.01 to 0.04 mg/100g) obtained for vitamin B2 are lower than the US RDA for children (0.4 to 0.8 mg/100mg) and for adults (1.1 to 1.7 mg/100g).

From the results of the vitamin contents of the samples presented in Table 4, It is evident however that crackers samples prepared from the flour blends of wheat, maize-African yam bean seed, and cassava cortex were higher in vitamins (vitamins A, B2, and E) than the control sample (sample WC). This may be attributed to the relatively high vitamins in the flour blends added.

More so, it is a known fact that vitamins are heat labile, thus some reduction or changes in the vitamin contents of the samples is expected to occur and this could be attributed to the heat treatment given to the product during baking.

Residual Anti-Nutrient Contents of Crackers Samples from Wheat, Maize–African Yam Bean Seed and Cassava Cortex Flour Blends

The result of the residual anti nutrient contents of the formulated samples is shown in Table 5. The phytate content of the samples ranged from 2.25 to 2.75 %. There was a significant (p < 0.05) difference in the phytate content of sample WC (control sample) compared to other blended samples but there was no significant (p > 0.05) difference between samples WC and MC (made from 70% wheat flour and 30% maize – African Yam bean seed flour). According to Oke [33], a phytate diet of 1-6 % over a long period decreases the bioavailability of mineral elements in monogastric animals. The phytate values observed in this study fall within the safe level of phytate for humans. Phytate binds to such minerals as calcium, zinc, manganese, and iron to form complexes that are indigestible, thereby decreasing the bioavailability of these elements for absorption [34].

The oxalate content of the samples ranged from 0.25 to 0.84 %. There was a significant (p < 0.05) difference in the oxalate content of sample WC (control sample) compared to other blended samples but there was no significant (p > 0.05) difference between samples WC and MC (made from 70 % wheat flour and 30 % maize – African yam bean seed flour). The highest value (0.84 %) of oxalate was observed in samples CF3 and CF4 which are samples with a high level of cassava cortex flour that is 15 and 20 % respectively.

The samples also showed significant (p < 0.05) differences in their cyanide contents but there was no significant (p > 0.05) difference between samples WC (control sample) and MC. Sample CF4 (made from 50 % wheat flour, 30 % maize – African yam bean seed flour and 20 % cassava cortex flour) had the highest cyanide content of 0.53 % and sample WC (made from 100 % wheat flour) had the lowest cyanide content value of 0.20 %. This low value of cyanide observed in sample WC can be attributed to the low cyanide content in wheat flour and the high cyanide content observed in sample CF4 may be attributed to the high level of cassava cortex flour incorporation in the sample. This cyanide level compares well with the recommended cyanide levels by FAO/WHO [35] which is 10 %, to prevent acute toxicity in humans. It is a known fact that heat reduces the anti-nutrient contents of food and food products when the heat is applied. However, the anti-nutrient content in the baked products in this study can be compared to the work of Okpala LC, Okoli [27], who reported low levels of hydrogen cyanide (1.6 to 2.4 %), for cookies produced from pigeon pea, cocoyam, and sorghum flour blends.

The alkaloid content observed in the samples ranged from 0.36 to 0.97 %. There was a significant (p < 0.05) difference in the alkaloid content of sample WC (control sample) when compared with other blended samples. The control sample (WC) had the lowest value (0.36 %) of alkaloid compared to other blended samples. However, this value is within the permissible or safe level of alkaloids for humans which is 0.2 to 0.97 % [36].

The tannin content in the samples ranged from 0.21 to 0.27 %. There was no significant (p > 0.05) difference in the tannin content of the sample WC (control sample) when compared with other blended samples. Tannin content observed is within the acceptable/ permissible range. According to Ifie and Emeruwa (34) reported that high levels of tannins (7.6 to 9.0 %) could be detrimental if consumed. This is because of its ability to bind with proteins of saliva and mucosal membranes. The increase in the anti-nutrient content of the blended samples when compared with the control sample could be attributed to the African yam bean seed and cassava cortex flours added to the samples.

Microbial Count of Crackers Samples from Wheat Flour, Cassava Cortex Flour and Maize – African Yam Bean Seed Blends

The result of the microbial count of the samples is shown in Table 6. The samples had low bacteria and mould count. The mould count as shown in the Table below is 0.3 x 10 cfu/g. There was no visible mould growth found in all the samples except for sample CF4.

The bacteria count in the samples ranged from 0.12 x10 to 0.8 x 102 cfu/g. The highest bacteria count (0.8 x 102 cfu/g) was observed in sample CF4 containing 50 % wheat flour, 30 % maize - African yam bean flour and 20 % cassava cortex flour. There was no visible bacteria growth found in all the samples except for samples CF4 and CF1 as shown in Table 6. The bacteria count (0.75 x 102 – 1.2 x 102 cfu/g) reported by Nagi  et al. [37] for biscuit made from cereal bran compared favorably with the result observed in this study.

In terms of Coliform, it was observed that there was no growth detected in all the samples analyzed. In all the microbial parameters determined, the control sample (sample WC) had no visible mould, bacteria, and coliform counts. This study has demonstrated that crackers produced from wheat, maize-African yam bean seed, and cassava cortex flour blends are microbially safe for consumption [38].

Sensory Scores of Crackers Samples from Wheat Flour and Maize – African Yam Bean Seed Flour Blends

Table 7 shows the mean sensory scores of crackers made from composite of maize – African yam bean seed flour and wheat flour (i.e. the preliminary study done from where the 70:30 ratios of wheat flour: maize-African yam bean seed flour was obtained before it was further combined/blended with cassava cortex flour as shown in Table 1). Except for the sample color, most other sensory attributes had acceptable ratings. The mean scores for flavor ranged from 5.85 to 8.20, taste ranged from 5.64 to 8.25, texture ranged from 6.15 to 7.95 and overall acceptability ranged from 5.57 to 8.25. The control sample (sample A) made from 100 % wheat flour had significantly (p < 0.05) higher scores in all the attributes than the blended samples. It was observed that the level/degree of preference for all the attributes decreased with increase in the level of substitution of maize–African yam bean seed flour in the blended samples. There was a significant (p < 0.05) difference between sample A and other blended samples in terms of color, flavor, taste, texture and overall acceptability except for sample B which had no significant (p > 0.05) in the texture when compared with sample A. However, sample B (70 % wheat flour and 30 % maize-African yam bean seed flour) was the most preferred among the blended samples. Expectedly, an increase in the level of inclusion of maize-African yam bean seed flour in the blended samples caused a significant decrease in the sensory scores of the samples as assessed by the panelists.

Effect of Incorporation of Cassava Cortex Flour On the Organoleptic Properties of Crackers Produced from Wheat and Maize – African Yam Bean Seed Composite Flour

Results of the mean sensory scores of the samples from cassava cortex flour, wheat flour, and maize – African yam bean seed flour blends are shown in Table 8. The control sample (WC) had significantly (p < 0.05) higher scores than other blended samples in all the attributes (flavor, taste, texture, and color) evaluated. It was observed that there was a decrease in the mean scores of the attributes (color, flavor, taste, and texture) of the blended samples as the levels of the incorporation of a maize-African yam bean seed and cassava cortex flours increased. Hence, the decrease in the sensory/organoleptic properties of the blended samples which evidently affected the choices of the panelists as well as their judgment during sensory evaluation. And this resulted in low scores which the panelists meted for those blended samples whose sensory properties were impaired as the inclusion of the composite flours increased. A progressive decrease was observed in the mean scores for color, from 7.13 to 5.23, flavor (7.33 to 5.27), taste (7.70 to 4.85) and texture (7.45 to 5.40). There were significant (p < 0.05) differences in the flavor, taste and overall acceptability of all the samples. But in terms of color, there was no significant (p > 0.05) difference in sample WC (control sample) compared to other blended samples except for samples MC and CF1. Also, there was no significant (p > 0.05) difference in the texture of sample WC (control sample) compared to other blended samples except for samples MC and CF2 as shown in Table 8. The scores of the overall acceptability decreased from 7.50 observed in sample WC made from 100 % wheat flour (control sample) to 4.97 in sample CF4 which had the highest level (20 %) of cassava cortex flour. However, in terms of the overall acceptability, sample WC had the highest value (7.50) among all the samples and was the most preferred by the panelists.

Broyant et al. [39] reported that the initial acceptance of baked products is much influenced by color which can also be an indicator of baking completion. The high mean scores observed for color and other organoleptic attributes seem to indicate that all the biscuits were acceptable to the panelists except for sample CF4 (50 % wheat flour, 30 % maize-African yam bean seed flour and 20 % cassava cortex flour) which was the least preferred by the panelists shown by its low mean scores for color, flavor, taste, texture and overall acceptability. The observed low scores for sample CF4 in all attributes was attributed to the high level (20 %) of cassava cortex flour added.

Conclusion and Recommendation

Conclusion

Crackers were formulated from wheat, maize, African yam bean seed, and cassava cortex flours. Analysis carried out showed that the formulated crackers had a slight reduction in protein with an increase in the ash, crude fiber, calcium and vitamin contents of the blended samples. The formulation of the crackers by incorporating cassava cortex flour has, however, provided another utilization of cassava cortex as a means of waste management. The crackers produced had a low microbial load and thus could be stored for a longer time. Though the progressive blending of the samples with maize African yam bean seed and cassava cortex flours significantly increased the nutrient contents of the blended/fortified samples, the sensory properties were impaired as the addition of the flours increased. Thus, the acceptability of the blended/fortified samples decreased with an increase in the level of addition of the flours. However, sample CC (that the control sample made from 100% wheat flour) had the lowest nutrient content but was the most acceptable and preferred by the panelists.

Recommendations

Further studies should be carried out on the storage stability of the samples produced from the blends of wheat, maize - African yam bean seed and cassava cortex flours.

Ethical Review

This study does not involve any human or animal testing.

  Figure 1: Production of flour from maize.

 Source: Enwere (1998)

 

  Figure 2: Production of African yam bean seed flour.

 Source: Enwere (1998)

 

 

Figure 3: Production of cassava cortex flour.

Table 1: Proportions of Composite Flour from Wheat, Maize, African Yam Bean Seed, And Cassava Cortex.

Components Blending proportions (%) and Sample codes
WC   MC   CF1   CF2 CF3 CF4
Wheat flour 100 70 65 60 55 50
Maize-African yam bean blend flour 0 30 30 30 30 30
Cassava cortex 0 0 5 10 15 20

Note: Each composite flour was used in the preparation of crackers. WC= 100 % Wheat flour crackers, MC= 70 % wheat flour + 30 % Maize- African yam bean seed flour, CF1= 65 % wheat flour + 30 % Maize- African yam bean seed flour + 5 % Cassava cortex flour, CF2= 60 % wheat flour + 30 % Maize- African yam bean seed flour + 10 % Cassava cortex flour, CF3= 55 % wheat flour + 30 % Maize- African yam bean seed flour + 15 % Cassava cortex flour, CF4= 50 % wheat flour + 30 % Maize- African yam bean seed flour + 20 % Cassava cortex flour.

Table 2: Proximate Composition of Cracker Samples Formulated with Blends of Wheat, Maize-African Yam Bean Seed and Cassava Cortex Flour (%).

Samples Crude protein Ash Moisture Crude fiber Fat Carbohydrate
  WC 4.41f±0.01 2.05 d±0.01 4.85f±0.30 1.55e±0.14 19.10b±0.07 68.24a±0.42
  MC 9.33a±0.03 2.20bc±0.03 5.15e±0.11 1.62d±0.05 18.24d±0.06 64.05d±0.14
  CF1 7.11b±0.01 2.25b±0.01 5.30d±0.05 1.70d±0.20 18.55c±0.03 65.54b±0.17
  CF2 7.05c±0.03 2.15c±0.01 5.55c±0.11 1.92c±0.20 19.20b±0.03 64.50c±0.10
  CF3 6.76d±0.01 2.50a±0.03 5.75b±0.07 2.02b±0.21 19.70a±0.04 63.30e±0.18
  CF4 5.25e±0.01 2.55a±0.03 7.45a±0.03 2.14a±0.30 17.94e±0.08 64.46cd±0.10

Note: Values are means of ± S.D of duplicate determinations. Mean values with different superscripts within the same column are significantly (p < 0.05) different. WC= 100 % Wheat flour crackers, MC= 70 % wheat flour + 30 % Maize- African yam bean seed flour, CF1= 65 % wheat flour + 30 % Maize- African yam bean seed flour + 5 % Cassava cortex flour, CF2= 60 % wheat flour + 30 % Maize- African yam bean seed flour + 10 % Cassava cortex flour, CF3= 55 % wheat flour + 30 % Maize- African yam bean seed flour + 15 % Cassava cortex flour, CF4= 50 % wheat flour + 30 % Maize- African yam bean seed flour + 20 % Cassava cortex flour.

Table 3: Mineral Composition of Crackers Produced the Flour Blends from Wheat, Maize-African Yam Bean Seed, And Cassava Cortex Flour Blends.

  Minerals
Samples    Iron (%) Calcium (%) Phosphorus (mg/100g)
  WC 0.27c±0.11 0.08ab±0.03 136.80a±0.01
  MC 0.37b±0.01 0.02b±0.02 94.46d±0.01
  CF1 0.19d±0.01 0.02b±0.01 100.26c ±0.01
  CF2 0.28c±0.03 0.06ab±0.03 74.91e±0.03
  CF3 0.46a±0.03 0.10a±0.01 58.89f±0.01
  CF4 0.11e±0.03 0.10a±0.03 104.23b±0.11

Note: Values are means of ± S.D of duplicate determinations. Mean values with different superscripts within the same column are significantly (p < 0.05) different. WC= 100 % Wheat flour crackers, MC= 70 % wheat flour + 30 % Maize- African yam bean seed flour, CF1= 65 % wheat flour + 30 % Maize- African yam bean seed flour + 5 % Cassava cortex flour, CF2= 60 % wheat flour + 30 % Maize- African yam bean seed flour + 10 % Cassava cortex flour, CF3= 55 % wheat flour + 30 % Maize- African yam bean seed flour + 15 % Cassava cortex flour, CF4= 50 % wheat flour + 30 % Maize- African yam bean seed flour + 20 % Cassava cortex flour.

Table 4: Vitamin Composition of Crackers Made from Blends of Wheat, Maize-African Yam Bean Seed, And Cassava Cortex Flours.

  Vitamins
Samples Vitamin E (mg) Vitamin A (IU) Vitamin B2 (mg)
  WC 1.40c±0.04 129.03b±0.03 0.01a ±0.06
  MC 1.40c±0.03 580.65a±0.21 0.02a±0.00
  CF1 1.40c±0.01 529.03a±0.04 0.03a±0.01
  CF2 1.40c±0.07 580.65a±0.11 0.04a±0.11
  CF3 1.60b±0.04 580.65a±0.05 0.02a±0.01
  CF4 2.20a±0.03 580.65a±0.07 0.03a±0.03

 

Note: Values are means of ± S.D of duplicate determinations. Mean values with different superscript within the same column are significantly (p < 0.05) different. WC= 100 % Wheat flour crackers, MC= 70 % wheat flour + 30 % Maize- African yam bean seed flour, CF1= 65 % wheat flour + 30 % Maize- African yam bean seed flour + 5 % Cassava cortex flour, CF2= 60 % wheat flour + 30 % Maize- African yam bean seed flour + 10 % Cassava cortex flour, CF3= 55 % wheat flour + 30 % Maize- African yam bean seed flour + 15 % Cassava cortex flour, CF4= 50 % wheat flour + 30 % Maize- African yam bean seed flour + 20 % Cassava cortex flour.

Table 5: Residual Anti-Nutrient Contents of the Crackers Samples Produced from The Flour Blends of Wheat, Maize-African Yam Bean Seed, And Cassava Cortex.

Samples Anti-nutrients (%)
  Oxalate Phytate Cyanide Alkaloids Tannins
  WC 0.42b±0.01 2.50b±0.01 0.20e±0.01 0.36e±0.03 0.25ab±0.01
  MC 0.42b±0.03 2.25c±0.11 0.25e±0.04 0.97a±0.50 0.21b±0.03
  CF1 0.25d±0.06 2.25c±0.01 0.33d±1.00 0.92a±0.20 0.21b±0.05
  CF2 0.34c±0.00 2.75a±0.03 0.40c±0.15 0.86b±0.15 0.27a±0.00
  CF3 0.84a±0.07 2.25c±0.03 0.48b±0.02 0.74c±0.20 0.26ab±0.01
  CF4 0.84a±0.00 2.25c±0.03 0.53a±0.05 0.62d±0.22 0.25ab±0.03

Note: Values are means of ± S.D of duplicate determinations. Mean values with different superscripts within the same column are significantly (p < 0.05) different. WC= 100 % Wheat flour crackers, MC= 70 % wheat flour + 30 % Maize- African yam bean seed flour, CF1= 65 % wheat flour + 30 % Maize- African yam bean seed flour + 5 % Cassava cortex flour, CF2= 60 % wheat flour + 30 % Maize- African yam bean seed flour + 10 % Cassava cortex flour, CF3= 55 % wheat flour + 30 % Maize- African yam bean seed flour + 15 % Cassava cortex flour, CF4= 50 % wheat flour + 30 % Maize- African yam bean seed flour + 20 % Cassava cortex flour.

Table 6: Microbial Counts of Crackers Samples from Wheat, Maize-African Yam Bean Seed, And Cassava Cortex Flour Blends.

Samples (cfu/g) (cfu/g) (cfu/g)
    Bacteria count    Mould count Coli form count
  WC NG NG NG
  MC NG NG NG
  CF1 0.12 x 10 NG NG
  CF2 NG NG NG
  CF3 NG NG NG
  CF4 0.8 x 102 0.3 x 10 NG

Note: Values are mean ± SD of triplicate determination. NG = No growth. WC= 100 % Wheat flour crackers, MC= 70 % wheat flour + 30 % Maize- African yam bean seed flour, CF1= 65 % wheat flour + 30 % Maize- African yam bean seed flour + 5 % Cassava cortex flour, CF2= 60 % wheat flour + 30 % Maize- African yam bean seed flour + 10 % Cassava cortex flour, CF3= 55 % wheat flour + 30 % Maize- African yam bean seed flour + 15 % Cassava cortex flour, CF4= 50 % wheat flour + 30 % Maize- African yam bean seed flour + 20 % Cassava cortex flour.

Table 7: Sensory Scores of Crackers Made from Wheat, Maize-African Yam Bean Seed Flour Blends.

Substitution level (%) WF:    MAF Color Flavor Taste Texture Overall Acceptability
      A 8.20a±0.89 8.20a±0.89 8.25a±0.79 7.95a±0.89 8.25a±0.79
      B 7.30b±0.92 7.30b±0.92 6.90b±1.33 7.65ab±1.27 7.10b±1.07
      C 7.25b±1.02 6.55bc±1.39 6.75b±1.59 6.80bc±1.70 6.7b±1.72
      D 7.05b±1.39 6.40c±1.57 6.30bc±1.30 6.90bc±1.37 6.40bc±1.05
      E 7.15b±1.04 5.85c±1.42 5.64c±1.66 6.15c±1.98 5.57c±1.09

Note: Values are mean ±SD (n=20). Mean values with different superscripts on the same column are significantly (p < 0.05) different. A= 100 % Wheat flour crackers, B= 90 % wheat flour and 10 % maize-African yam bean seed flour, C= 80 % wheat flour and 20 % maize-African yam bean seed flour, D= 70 % wheat flour and 30 % maize-African yam bean seed flour, E= 60 % wheat flour and 40 % maize-African yam bean seed flour.

Table 8: Sensory Scores of Crackers Made with Composite Flours from Wheat, Maize-African Yam Bean Seed, And Cassava Cortex Flours.

Sample Color Flavor Taste Texture Overall Acceptability
  WC 7.13b±0.45 7.33a±0.56 7.70a±0.51 7.45a±0.48 7.50a±0.68
  MC 6.13b±0.77 6.73b±0.80 6.67b±0.95 6.40ab±0.88 5.77b±0.85
  CF1 6.37b±0.70 5.93bc±0.47 5.73bc±0.55 5.60c±0.73 5.50c±0.65
  CF2 5.25c±0.87 5.40bc±0.74 5.29d±0.76 5.97ab±0.83 5.83bc±0.75
  CF3 5.32c±0.90 5.93bc±0.93 5.29d±0.76 5.87bc±0.81 5.34d±0.60
  CF4 5.23c±1.12 5.27c±0.89 4.85e±0.82 5.40c±1.13 4.97e±0.85

Note: Values are mean of 30 determinations ± SD. Means with different superscripts on the same column are significantly (p < 0.05) different. Mean values with different superscripts within the same column are significantly (p < 0.05) different. WC= 100 % Wheat flour crackers, MC= 70 % wheat flour + 30 % Maize- African yam bean seed flour, CF1= 65 % wheat flour + 30 % Maize- African yam bean seed flour + 5 % Cassava cortex flour, CF2= 60 % wheat flour + 30 % Maize- African yam bean seed flour + 10 % Cassava cortex flour, CF3= 55 % wheat flour + 30 % Maize- African yam bean seed flour + 15 % Cassava cortex flour, CF4= 50 % wheat flour + 30 % Maize- African yam bean seed flour + 20 % Cassava cortex flour.

Citation: Okoye EC, Ani JC, Ugwuanyi, Ruth G, Oyeoku OC (2020) Quality Assessment of Crackers from the Flour Blends of Wheat, Maize-African Yam Bean Seed and Cassava Cortex. J Clin Nutr Food Chem. 1: 002. JCNFC-002.000002