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Research Article | DOI: https://doi.org/10.31579/2637-8914/290
Department of Home Economics, Federal College of Education (Special), Oyo, Nigeria.
*Corresponding Author: Akinsola, A.O, Department of Home Economics, Federal College of Education (Special), Oyo, Nigeria.
Citation: Akinsola, A.O., Oyeleye, B.R., Taiwo-Oshin, M.A., Afonja, T.E., and Gbadegesin I, A, et al, (2025), Nutritional characteristics and sensory properties of orange fleshed sweet potato-based complementary food fortified with pigeon pea (Cajanus cajan) and tigernut (Cyperus esculentus) composite flours, J. Nutrition and Food Processing, 8(2); DOI:10.31579/2637-8914/290
Copyright: © 2025, Akinsola, A.O. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received: 02 January 2025 | Accepted: 21 January 2025 | Published: 10 February 2025
Keywords: complementary food; composite flour; fortification; infants, nutritional beneficial; young children
The study evaluates nutritional characteristics and sensory properties of orange fleshed sweet potato-based complementary food fortified with pigeon pea and tigernut composite flour. Standard processing and analytical methods were used in material preparation and analyses for the composite flour blends. The composite flours were blended in ratio of 100:0:0, 60:30:10, 65:25:10, 70:20:10, 75:15:10 and labeled A, B, C, D and E, respectively. Result shows that there was significant improvement (p< 0.05) in the proximate composition of all the composite flours determined. Significant (P<0.05) difference exists across the samples for Ca, Fe, P, K, Na and Mg with values ranging from 38.12 to 54.55 g/100g, 2.87 to 4.18 g/100g, 48.16 to 68.60 g/100g, 89.40 to 148.17 g/100g, 1.83 to 3.13 g/100g and 92.60 to 119.57 g/100g, respectively. There was significant difference (p < 0.05) among all samples for all the vitamin assayed with values ranging from 1432.14 to 1746.85 (RAE), 0.06 to 0.17 g/100g, 0.03 to 0.10 g/100g, 0.05 to 0.12 g/100g and 13.42 to 17.26 g/100g for vitamin A, B1, B2, B3 and C, respectively while negligible amounts of antinutritional factors obtained ranged from 0.42 to 1.71 mg/100g, 0.17 to 1.14 g/100g, 0.81 to 1.67 g/100g, 1.79 to 1.42 g/100g and 0.38 to 1.54 g/100g for phytate, oxalate, tannins, amylase and trypsin inhibitors, respectively. Sensory evaluation mean scores revealed substantial overall acceptability of all the formulated complementary food samples while sample with 25 % pigeon pea and 10 % tigernut was most preferred by the panelists. The quality of OFSP-based complementary samples were greatly improved by pigeon pea and tigernut fortification and could be nutritional beneficial to infants and young children.
The development of quality complementary foods from local and readily accessible raw materials has received considerable attention in many developing countries especially Nigeria in order to reduce dependant on foreign currency and guarantee quality complementary foods are given to infants and young children in addition to breast milk when breast milk nutrients become insufficient for their energy and growth needs (Olorode et al., 2017). In developing West African countries such as Nigeria, the introduction of complementary food typically usually starts between the ages of three to six months (i.e. within six months of exclusive breast feeding). Complementary food is an important phase in the transition from breast feeding to family foods in form of semi-liquid porridge prepared from staple cereals and tubers such sweet potato, cocoyam, Irish potato, etc. Orange fleshed sweet potato, OFSP (Ipomoea batatas) has considerable antioxidant activity and very rich in carotenoids and β-carotene (containing 24.2 – 7.9 mg/100 g of β-carotene on dry basis), a precursor of vitamin A (Alam et al., 2016) which protects the body from several diseases, such as night blindness and other serious diseases. Orange fleshed sweet potato roots are source of fibre, starch, sugar, vitamin A, iron, calcium and several other minerals (Browser et al., 2017) potentially improve vitamin A level in growing children in developing countries (Laurie et al., 2015).
Pigeon pea (Cajanus cajan) seeds can be used as a vegetable and cooked in curries or used to make relishes. The dry seeds have several products according to Nwosu et al. (2013) such as tempe and ketchup. Pigeon pea flour mixed with wheat to improve the protein level of baked products) and clear noodles of a quality higher than that of mung bean are made from dehulled seed. Fresh seeds contain vitamins, especially provitamin A and vitamin B complex per 100 g edible portion, its dry seeds contain 7-10.3 g water, 14-30 g protein, 1-9 g fat, 36-65.8 g carbohydrates, 5-9.4 g fibre and 3.8 g ash. The energy content averages 1450 kJ/100 g while tigernut (Cyperus esculentus) is a high dietary fibre tuber crop which could be utilized in the treatment and prevention of many disease including colon cancer, coronary heart diseases, obesity and gastro intestinal disorder as reported by (Oke et al., 2016). Its flour has been observed to be rich source of quality oil, vitamin E and some useful minerals such as iron and calcium which are essential for body growth and development (Oke et al., 2019). Therefore, addition of pigeon pea and tigernut flour in complementary food formulations for indigenous tubers will improved its protein quality, micronutrients, vitamin A and dietary fibre. Vitamin A deficiency has far reaching consequences and can lead to common illness in children such as vision and immune impairment It is thus, a priority in health policy to improve vitamin A and pro-vitamin A status in these vulnerable groups especially children (Akinsola et al., 2018).
It is inevitable necessary to study ways and means of developing inexpensive but equally nutritious traditionally produced complementary food that may be within the reach of the under privilege, using locally available cereals, legumes and cottage technologies in its production. The formulation of quality complementary foods from local and readily available raw materials such as orange flesh sweet potato, pigeon pea and tigernut is expected to provide protein based weaning foods that are of high quality and inexpensive. Therefore, the main objective of this study was to determine the nutritional characteristics and sensory properties of orange fleshed sweet potato-based complementary food fortified with pigeon pea and tigernut composite flour.
Materials
Orange fleshed sweet potato roots were purchased from a popular farm market in Offa, Kwara State while pigeon pea and tigernut (yellow variety) were purchased at Ajegunle market, Oyo, Oyo State, Nigeria.
Production of orange fleshed sweet potato (Ipomea batata) flour
The orange fleshed sweet potato flour was produced according to the standard method of Singh et al. (2008) described by Alawode et al. (2017). The orange fleshed sweet potato tubers were peeled and cut into thin slices manually with sharp knives. The sweet potato slices were soaked in 1 % potassium metabisulphite solution for a period of five minutes to avoid browning and intensify its colour, then dried in a cabinet dryer set at 55±5 °C for 48 hours. The dried orange fleshed sweet potato chips were milled into flour using laboratory hammer mill (Fritsch, D-55743, Idar-Oberstein, Germany) to fine powder. The milled flour obtained were sieved using 250 μm screen, packaged in a sealed plastic film and stored in a closed plastic container till further use.
Production of pigeon pea (Cajanus cajan) flour
The modified method described by Okolie et al. (2022) was used for pigeon pea seed. The pigeon peas were cleaned to remove extraneous elements such as stones, deformed bean and pest-infested beans. The seeds were washed and steeped in tap water for 24 hours and dehulled. Dehulled seeds were dried in the cabinet dryer at 55±5 °C for 48 hours. The seeds were dry milled after cooling into flour using the laboratory hammer mill (Fritsch, D-55743, Idar-Oberstein, Germany) to fine powder. The milled flour obtained was sieved using 250 μm screen, packaged in a sealed plastic film and stored in a closed plastic container till further use.
Production of tigernut (Cyperus esculentus) flour
Tigernut flour was produced by the method described by Oke et al. (2017). After removing stones, pebbles and other unknown materials from the tigernut and clean under running tap water. The cleaned nuts were then dried in a cabinet dryer at 55±5 °C for 48 hours. The dried nuts were milled in a laboratory hammer mill (Fritsch, D-55743, Idar-Oberstein, Germany) to fine powder. The milled flour obtained was sieved using 250 μm screen, packaged in a sealed plastic film and stored in a closed plastic container till further use.
Formulation of OFSP, pigeon pea and tigernut composite flour
The OFSP-based complementary flours were mixed in proportion of 100:0:0; 75:15:10; 70:20:10; 65:25:10; 60:30:10, respectively and coded as sample A, B, C, D and E. Sample B – E was blended using a Kenwood mixer (Model: HC 750D, Kenwood, UK) to produce homogenized composite flour while sample A served as control and contained 100 % OFSP flour. The composite flours of the four samples were formulated with equal tigernut flour obtained and stored at room temperature (28±2 oC) in an airtight low-density polyethylene bag for further analysis.
Methods
Determination of proximate composition of OFSP, pigeon pea and tigernut composite flour
Proximate composition (moisture, protein, fat, fibre, ash) of each sample was carried out using Association of Official Analytical Chemistry (2016) while carbohydrate content was determined by difference. Gross energy value of each sample was determined by calculation from fat, carbohydrate and protein content using the Famakin et al. (2016) method:
Gross energy, KJ/100 gm (Dry matter) = (Protein x 16.7) + (Lipid x 37.7) + (Carbohydrate x 16.7)
Determination of mineral content of OFSP, pigeon pea and tigernut composite flour
The mineral concentration (Ca, Fe, K, Na, P, Mg) was determined using the Atomic Absorption Spectrophotometer (Model: 6405 UV/VIS, Jenway, UK) according to AOAC (2016). The ash obtained after incineration at 500°C was dissolved in aquaregia (10 mL nitric acid +30 mL HCl) solution and boiled for 30min. The mixture was transferred into a 250mL volumetric flask and boiled again for 30min. The mixture was filtered into 100mL volumetric flask and made up to the mark with distilled water and injected into the Spec equipped with a UV detector set at 254 nm. The peaks of the minerals in the samples were calculated in relation to the peaks of standard minerals.
Determination of vitamin content OFSP, pigeon pea and tigernut composite flour
Vitamin A, B1, B2, B3 and C were evaluated using HPLC (Model: BLC-10/11, BUCK Scientific, USA) techniques as described by AOAC (2016). For each sample, 3.0 g was mixed with 5 mL of n-hexane and 20 mL of HPLC grade water. The mixture was homogenized at 12000 rpm and centrifuged (3500 x g) for 30 min, followed by sequential filtration through whatman No 1 filter paper and 0.45 µm membrane. Then, 15 µL of the supernatant was injected into the HPLC equipped with a UV detector set at 254 nm. The peaks of the vitamins in the samples were calculated in relation to the peaks of standard vitamins.
Determination of Anti-nutrients of OFSP, pigeon pea and tigernut composite flour
Selected anti-nutritional factors such as phytate, oxalate, tannins were determination using method described by Nwosu (2013) while amylase and trypsin inhibitor contents were determined as described by Figueira et al. (2003) and Famakin et al. (2016), respectively.
Sensory evaluation of the OFSP, pigeon pea and tigernut composite flour
The complementary food samples were prepared into gruel and presented to twenty semi-trained nursing mothers, lecturers and mothers of in School of Secondary School, Vocational and Technical programmes, Federal College of Education (Special), Oyo. Each sample was reconstituted, coded and evaluated for preference using the method of Akinsola et al. (2018). They were asked to score the complementary food samples for appearance, aroma, taste, texture and overall acceptability, respectively. Each panelist sat apart from one another for sensory evaluation. Water was provided to rinse mouths before and after tasting each of the samples. The panelists were presented with a score sheet using 9-point hedonic scale where 1 is disliked extremely and 9 liked extremely.
All data were statistically analyzed using SPSS version 17.0 for analysis of variance, while Duncan multiple range test (DMRT) was used to separate means where there is a significant difference. For each sample, triplicate determinations were carried out.
Proximate composition of OFSP, pigeon pea and tigernut composite flour samples
The result of proximate composition of oranges fleshed sweet potato (OFSP) based complementary food fortified with pigeon pea and tigernut flour is as shown in Table 1. The result indicates significant improvement in all the samples nutrients at alpha 0.05 except carbohydrate which reduces significantly as pigeon pea % increases in the formulation. Moisture content (M.C) reduced among the formulated complementary food samples compared with control sample (sample A). M.C values obtained was relatively lower than 10 % which indicated a good shelf life and nutrients dense complementary food products. Low M.C is a pre-requisite for longer storage ability of a food product since it will prevent quick mouldy of the blended flour. Protein values of the study were lower than the value (13-14 g/100g) recommended by Anigo et al. (2009). It was observed during the study that a protein of 10-12 g/100g dry weight significantly provides good protein nutrient to a baby of 6-23 months when a novice observation was carried out using a nearby maternity home to test the sample products. Samples with 20 %, 30 % and 30 % pigeon pea addition agreed with the work of Anigo et al. (2009) and Idowu et al. (2017). Fat content of all the samples provides more than 28 % of energy value of the baby food compared to FAO/WHO (1994) recommendation of 13 % of total energy provided by the food sample. Ash content of the complementary food samples was the residual organic material after ashing the food samples indicate indirectly amount of mineral content of the samples. There is statistical differences (p<0>
| Parameter (100 %) | Sample A | Sample B | Sample C | Sample D | Sample E |
| Moisture content | 9.24±0.00 | 9.63±0.16 | 9.18±0.21 | 8.72±0.02 | 8.84±0.11 |
| Protein | 5.81±0.00 | 8.67±0.02 | 10.40±0.12 | 10.83±0.11 | 11.40±0.00 |
| Crude fat | 1.62±0.03 | 3.69±0.00 | 4.71±0.03 | 4.37±0.12 | 5.62±0.01 |
| Crude ash | 2.62±0.11 | 3.73±0.20 | 4.81±0.10 | 4.09±0.11 | 5.09±0.11 |
| Crude fibre | 1.77±0.02 | 2.54±0.21 | 3.14±0.03 | 2.75±0.10 | 3.18±0.00 |
| Carbohydrate | 78.94±0.00 | 71.74±0.16 | 69.67±0.21 | 67.33±0.02 | 64.86±0.11 |
| Gross energy, KJ/100g | 1476±0.00 | 1480±0.02 | 1501±0.12 | 1482±0.11 | 1485±0.00 |
All values are expressed as mean ± SD of three replicate determinations. Mean values in the same column with different superscript are significantly different (p< 0>
Table 1: Proximate composition of OFSP, pigeon pea and tigernut composite flour samples
Mineral content of OFSP, pigeon pea and tigernut composite flour samples
Table 2 shows mineral content result of OFSP based complementary food samples fortified with pigeon pea and tigernut composite flours. The result indicates an increase trends in all the samples compared with control sample: Ca (38.12 - 54.55), Fe (2.87 - 4.18), P (48.16 - 68.60), K (89.40 - 148.17), Na (1.83 – 3.13) and Mg (92.60 – 119.57 g/100g), respectively. The Ca content significantly (p<0>
| Mineral, mg/100g | Sample A | Sample B | Sample C | Sample D | Sample E |
| Calcium, Ca | 38.12± 0.00 | 43.24± 0.01 | 50.63± 0.07 | 49.11± 0.01 | 54.55± 0.07 |
| Iron, Fe | 2.87± 0.01 | 3.41± 0.06 | 3.82± 0.01 | 4.03± 0.14 | 4.18± 0.63 |
| Phosphorus, P | 48.16± 0.01 | 55.39± 0.01 | 65.17± 0.07 | 61.25± 0.03 | 68.60± 0.06 |
| Potassium, K | 89.40± 0.01 | 103.11± 0.03 | 143.36± 0.28 | 137.23± 0.01 | 148.17± 0.07 |
| Sodium, Na | 1.83± 0.01 | 2.11± 0.00 | 2.83± 0.14 | 2.45± 0.03 | 3.13± 0.01 |
| Magnesium, Mg | 92.60± 0.01 | 104.12± 0.06 | 114.19± 0.01 | 110.65± 0.14 | 119.57± 0.63 |
All values are expressed as mean ± SD of three replicate determinations. Mean values in the same column with different superscript are significantly different (p< 0>
Table 2: Mineral content of OFSP, pigeon pea and tigernut composite flour samples
Vitamin content of OFSP, pigeon pea and tigernut composite flour samples
Vitamins content of all the samples are statistically (p<0>
| Vitamin, mg/100g | Sample A | Sample B | Sample C | Sample D | Sample E |
| A Calculated (RAE*) | 1423.14± 0.64 | 1581.33± 0.01 | 1627.11± 0.01 | 1746.85± 0.01 | 1664.25± 0.01 |
| Thiamin, B1 | 0.11± 0.01 | 0.18± 0.01 | 0.23± 0.01 | 0.26± 0.01 | 0.27± 0.01 |
| Riboflavin, B2 | 0.08± 0.01 | 0.12± 0.01 | 0.14±0.00 | 0.14± 0.01 | 0.16± 0.01 |
| Biotin, B3 | 0.10± 0.06 | 0.13± 0.02 | 0.16±0.01 | 0.18± 0.01 | 0.21± 0.02 |
| Ascorbic acid, C | 1.84± 0.42 | 2.09± 0.01 | 2.30±0.00 | 2.52± 0.01 | 2.73± 0.01 |
All values are expressed as mean ± SD of three replicate determinations. Mean values in the same column with different superscript are significantly different (p< 0>
Table 3: Vitamin content of OFSP, pigeon pea and tigernut composite flour samples
Anti-nutrient factors of OFSP, pigeon pea and tigernut composite flour samples
Table 4 shows results of anti-nutrient factors of OFSP, pigeon pea and tigernut composite flour blends. All the selected anti-nutrient factors determined decrease across the samples with sample E having the least value except in trypsin inhibitor value which increases from sample A (0.38 TIU) to sample E (1.54 TIU), respectively. This may be as result pigeon pea addition which increases the crude protein content of the formulated samples. Decrease in phytate value from sample A to sample E could be as a result of addition of pigeon pea and tigernut flours to the formulated complementary food samples. This result agreed with the work of Alawode et al. (2017) who work on OFSP, sorghum and soya beans complementary food. Oxalate values shows statistical differences (p<0>
| Anti-nutrient factor, mg/100g | Sample A | Sample B | Sample C | Sample D | Sample E |
| Phytate | 0.62± 0.01 | 0.47± 0.00 | 0.38± 0.02 | 0.31± 0.00 | 0.26± 0.01 |
| Oxalate | 0.47± 0.01 | 0.36± 0.00 | 0.29± 0.01 | 0.22± 0.00 | 0.14 ± 0.01 |
| Tannins | 0.81± 0.01 | 0.76± 0.00 | 0.62± 0.01 | 0.56± 0.00 | 0.52± 0.01 |
| Amylase inhibitors (AIU) | 1.79± 0.01 | 1.49 ± 0.00 | 1.28± 0.01 | 1.11± 0.00 | 0.69± 0.01 |
| Trypsin inhibitors (TIU) | 0.08± 0.00 | 0.13± 0.00 | 0.15± 0.00 | 0.18± 0.00 | 0.22± 0.00 |
All values are expressed as mean ± SD of three replicate determinations. Mean values in the same column with different superscript are significantly different (p< 0>
Table 4: Anti-nutrient factors of OFSP, pigeon pea and tigernut composite flour samples
Sensory property of the OFSP-based complementary food samples
The result of sensory evaluation of OFSP based complementary food with pigeon pea and tigernut flours is as shown in Table 5. Statistical differences (p<0>
This shows that addition of pigeon pea and tigernut flours to the blends improve its taste and aroma inclusive. Texture of sample E was least rated which may be as a result of pigeon pea addition that affect OFSP textural structure. Overall acceptability mean scores for the formulated samples indicates tasters preferences for sample D. This may be as a result its appearance, aroma and taste which rating (5.97) is second to sample C (6.01), respectively.
| Parameter | Sample A | Sample B | Sample C | Sample D | Sample E |
| Appearance | 6.09±0.34d | 5.76±0.31b | 6.56±0.22a | 6.88±0.34d | 5.46±0.41b |
| Aroma | 4.76±0.17cd | 6.02±0.40b | 5.88±0.26b | 6.34±0.17cd | 5.35±0.24cd |
| Taste | 5.12±0.32b | 5.14±0.47a | 6.01±0.20a | 5.97±0.32b | 5.69±0.45b |
| Texture | 5.35±0.34a | 5.67±0.33a | 6.45±0.21a | 6.62±0.34a | 5.12±0.38a |
| Overall acceptability | 5.43±0.03a | 6.18±0.42a | 6.87±0.20a | 7.03±0.03a | 5.86±0.42a |
All values are expressed as mean ± SD of three replicate determinations. Mean values in the same column with different superscript are significantly different (p< 0>
Table 5: Sensory property of the OFSP-based complementary food samples
The study results in proximate composition, mineral profile, vitamins, antinutrients factors and sensory attributes indicates that fortification of OFSP flour with pigeon pea and tigernut flours for complementary food formulation improves its macro and micro nutrients bioavailability for infants and young children. Moreover, sensory attributes mean scores shows that all the fortified samples were generally accepted by the panelists than the control sample which is 100 % OFSP flour. However, in term of overall acceptability sample D that contained 25 % pigeon pea and 10 % tigernut flours is best accepted.
The project was self-funded by the authors; there was no direct funding for the research. We declare no conflict of interest.
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