Nutrient composition of CP, PN, and CB
The results from the chemical analyses of CP, PN, and CB served as a complementary guide to the ESHA software in the preparation of the composite flour for the formulation of the WF. Moisture contents of the three samples were significantly different with values of 5.44%, 1.86%, and 3.68% for CP, PN, and CB, respectively (Table 1). The high moisture content of the CP could be attributed to the high level of water absorbed by the seeds during soaking and boiling. Ripe CB is known for its high moisture content, and 24 h drying at 60°C is not sufficient to reduce the moisture content below this level. Employing higher temperatures will have an adverse effect on the sample. PNs naturally have very low moisture content coupled with the high roasting temperature.
Table 1. Proximate composition and calorie content of raw materials: cowpea (CP), peanut (PN), and cooking banana (CB)
|CP||5.44 ± 0.02A||2.45 ± 0.05A||1.85 ± 0.06B||25.31 ± 0.12B||64.95 ± 0.06B||377.67 ± 0.23B|
|PN||1.86 ± 0.03C||2.21 ± 0.04A||51.11 ± 0.53A||27.50 ± 0.02A||17.32 ± 0.13C||639.27 ± 0.77A|
|CB||3.68 ± 0.02B||2.08 ± 0.05A||0.50 ± 0.05C||2.78 ± 0.14C||90.96 ± 0.14A||379.45 ± 0.50B|
The higher ash content of CP compared with PN and CB probably indicates a higher mineral content. Oil contents of the samples were 1.85% (CP), 51.11% (PN), and 0.50% (CB). This served as an indicator for the amount of PN to be added to the product. The protein content was 25.31%, 27.50%, and 2.78% for CP, PN, and CB, respectively, showing the need for the fortification of CB with these legumes. The carbohydrate contents were 64.95% (CP), 17.32% (PN), and 90.96% (CB) while the calorie content was 377.67, 639.27, and 379.45 kcal for CP, PN, and CB, respectively. The high calories for PN despite the low carbohydrate content indicates that fat is the major contributor here.
The pH values of the legumes were significantly higher than that of CB (P ≤ 0.05) and in the order CP>PN>CB with values of 6.68, 6.51, and 4.58, respectively. The high acidity of the CB could be attributed to the ascorbic acid content of the ripe fruit coupled with the aqueous lime juice solution used for steeping the banana to inhibit enzymatic browning.
Table 2 shows the nutrient composition obtained for the novel WF compared with that of two commercial WFs processed from RB and OB. Carbohydrate was the predominant component of all three samples followed by protein. In the case of the novel WF, fat was the next dominant component with a value of 8.38% compared with 1.10% and 3.16% for RB and OB, respectively. From Table 2 it can be seen that the novel WF has the highest amount of protein (16.89 g) in 100 g of the food with 6.9 g and 12.03 g for RB and OB, respectively. The moisture content was observed to be in the order 4.42%, 5.32%, and 5.45% for WF, RB, and OB, respectively. Dietary fiber of the formulated food was 13.05 g.
Table 2. Nutrient composition of weaning food (serving size 100 g)
|WF: weaning food from our study||4.42 ± 0.03B||16.89 ± 0.21A||2.16 ± 0.11C||8.38 ± 0.01A||68.16 ± 0.38C||415.59 ± 0.53A|
|RB: commercial weaning food (rice with banana)||5.32 ± 0.05A||6.90 ± 0.20C||3.98 ± 0.09A||1.10 ± 0.00C||82.70 ± 0.14A||368.31 ± 0.46C|
|OB: commercial weaning food (oats with banana)||5.45 ± 0.13A||12.03 ± 0.05B||3.02 ± 0.60AB||3.16 ± 0.03B||76.34 ± 0.14B||381.90 ± 0.50B|
The moisture content of the novel WF was significantly lower than that of the commercial products, with values of 4.42, 5.32, and 5.45 for the WF, RB, and OB, respectively. The low moisture content of the WF will have a positive effect on its shelf stability as the higher the moisture content the less stable the food will be toward oxidation reactions if other environmental factors are favorable.
The ash content on the other hand was in the order RB>OB>WF with values of 3.98%, 3.02%, and 2.16%, respectively. The high ash content of OB and RB indicates a high mineral content compared with the ash content of the formulated WF which indicates the least mineral content. The RB and OB may have been fortified with iron and other minerals which may account for the high mineral/ash contents.
A low-cost infant weaning formula based on locally available indigenous foods in India (maize and green gram) provided 11.5 g protein and 305 kcal per 80 g (Devadas et al. 1974). Gahlawat and Sehgal (1993) in their work obtained protein content in the range of 13.9–14.2% and moisture, ash, fat, and calories in the range of 5.45–6.15%, 4.20–4.61 g, 1.27–1.60 g, and 348–364 kcal per 100 g, respectively. Keshinro et al. (1993) recorded nutrient composition of ogi porridge as 1.0% protein and a caloric value of 100 kcal/100 g with no appreciable oil. Kluvitse (1999) designed two weaning formulations with the aid of computer software from maize, CP, PN, and soybean oil and obtained protein and oil content in the range of 17.5–20.0 g/100 g and 7.8–9.1 g/100 g, respectively. Chandbrasekhar et al. (1988) developed mixtures from malted ragi and horse gram and roasted PNs, which contributed 412 kcal energy and 13 g of protein. Dahiya and Kapoor (1993) reported moisture in the range of 5.37–6.16%, protein 11.7–12.8%, fat 5.08–5.98%, fiber 1.26–1.61%, ash 1.91–2.20%, carbohydrate 72.5–73%, and energy 389–392 kcal for WF processed from locally available foods. Sheikh et al. (1986) also reported 6.5% moisture and 19.4% protein in the soybean weaning mixtures they formulated. The processed WF compares favorably with these foods.
Nutrient requirements for infants up to 6 months of age were established from studies involving healthy infants who were exclusively breast fed by healthy mothers (FAO 1964; WHO 1985). The calculated energy requirements for a weaning infant ideally ranged from 414 kJ/kg per day for a 4- to 5-month old to 397 kJ/kg for the 8- to 9-month old (FAO 1973; WHO 1985). The PAG (protein advisory group) of the United Nations System recommended percentage w/w protein of 15.0% minimum if the NPU (net protein utilization) is above 80, but if it is within 60–80, a minimum level of 20% is required in every weaning/infant supplementary food (Kluvitse 1999). Fat is recommended to be (as much as feasible) up to 10% as long as it does not compromise the keeping qualities of the food; linoleic acid should be at least 1%, while ash must not exceed 5 g (Kluvitse 1999). The WF appears to meet these requirements.
Total sugar was recorded as 15.96 g/100 g, with fructose having the highest value of 8.07 g/100 g, followed by dextrose with a value of 7.66 g/100 g. The high content of fructose is probably as a result of the ripe CB used in formulation (Table 3).
Table 3. Sugar profile of formulated weaning food
|Total sugars||15.96 (g/100 g)|
|Dextrose||7.66 (g/100 g)|
|Lactose||<0.01 (g/100 g)|
|Sucrose||<0.01 (g/100 g)|
|Fructose||8.07 (g/100 g)|
|Maltose||0.23 (g/100 g)|
Fatty acid composition of the novel WF and that predicted by ESHA is shown in Table 4. Values predicted for some of the fatty acids did not tally with obtained values. ESHA prediction for hexadecanoic (palmitic) acid was 1.95% against 1.01%, octadecanoic (stearic) acid 0.56% against 0.22%, octadecatrienoic (linolenic) acid 0.1% against 0.29%, docosanoic (behenic acid) 0.09% against 0.2, and tetracosanoic (lignoceric) acid 0.02% against 0.13%. While values obtained for octadecenoic (oleic) acid 3.65% against 3.56% and octadecadienoic (linoleic) acid 2.64% against 2.22% are comparable. The data also showed that octadecenoic (oleic) acid which is a monounsaturated fatty acid had the highest value of 3.65% followed by octadecadienoic (linoleic) acid a polyunsaturated fatty acid with a value of 2.64% amounting to 76.69% of the total fatty acid. The relatively high percentage of unsaturated fatty acids is known to be desirable in food compared with their saturated counterparts because of their health benefits (Coultate 2002).
Table 4. Fatty acid profile of formulated weaning food
Essential amino acids of the WF were recorded as histidine 32.55 mg, isoleucine 38.88 mg, leucine 73.42 mg, lysine 59.28 mg, methionine + cystine 25.06 mg, phenylalanine + tyrosine 89.06 mg, threonine 36.86 mg, tryptophan 11.70 mg, and valine 46.19 mg, while dietary fiber, vitamin A, C, and E contents of the WF (Table 5) were 13.05%, 187 IU, 1.54 mg, and 0.84 IU, respectively (Bassey et al. 2009). The WF will need to be fortified with these vitamins. It was observed that some of the essential amino acids of the novel food were within the FAO/WHO 1989 recommended levels for 0–1 year while all were within levels recommended for 2–5 year FAO/WHO (WHO 1985).
Table 5. Dietary fiber, vitamins A, C, E, and iron content of weaning food (WF)
|Standard valuesa (0.5–0.9 years)||19||200||0.55||400||40||4|