INTRODUCTION
In Africas local language, weaning is merged in breast-feeding substitution by solid food. Therefore, from fourth to sixth months the infant is bound to family meals or to eating gruels made of cereal or tuber flours. Even, if cereals and tubers represent important carbohydrates and fibres source for worldwide population (Helland et al., 2002), their nutritional quality and their derivate products remain poor than milk products (Blandino et al., 2003). In deed on the one hand, the composition in nutriment of babys cereal is poor (De Benoist, 1994; Trèche, 1998); on the other hand, the richness in starch gives a high viscosity to the gruels (Moursi et al., 2003; Vieu et al., 2001). The limited gastric capacity in infants was about 30-40 ml / kg body weight (Sanchez-Grinan, et al., 1992). As matter of fact, preparing mush is not a simple flours cooking in water but that needs a mastery of the nutritional value of flour, consistency of mush and energy density.
Thats why, we suggested in this study weaning mush prepared from mixed flours of Taro, leguminous plant and malt maize with nutritional properties in accordance to WHO criteria (1998).
MATERIALS AND METHODS
Raw material plant: Raw materials used in mixed flours production were
constituted of low ground Taro (Colocasia esculenta), seeds of Pigeon
pea (Cajanus cajan) and malted maize (Zea mays).
Production of flours
Taro flour: Taro was peeled, washed, jagged, washing at 90oC
during 5 min and then dried in an incubator at 65oC during 5 days.
Then, the dried pieces of taro were crushed with a Forplex type grinder. Flour
was obtained after sieving with sieve diameter from 180-500 μm.
Malted maize flour: Seeds are soaked during 48 h then spread out on cloth humidified for 3 days. Malted maize is dried, sorted out, degermed and crushed. After sieving from 180-500 μm size sieves, malted maize flour was obtained.
Pigeon pea flour: Seeds are sorted, washed, roasted and then crushed with Forplex type grinder. Flour was obtained after sieving with size sieve diameter from 180-500 μm.
Preparation and characterization of weaning mush: Mush was prepared in aluminium saucepan and different proportions of Taro, Pigeon pea and malted maize flours were mixed in water (180 ml) in accordance with Mouquet method (1998). The flow distance (mm / 30 sec) of the gruels obtained was measured using a Bostwick consistometer according to the method used by Vieu et al. (2001). Dry Matter contents (DM) and consistency of mush were followed; the objective was to establish the best possible formulation.
Preparation of compound flour: The weaning flour is a mixing of Taro, Pigeon pea and malted maize flours and sucrose in proportions 58/18/14/10.
Biochemical analyses: The Dry Matter contents (DM) of 1g of sample was measured after flours drying in an oven at 105oC for 24 h according to AOAC (1990).
Ash content (5 g) was determined by incineration of flour at 500oC in an oven.
Chloride was determined by the method of mercury measurement, Phosphates by Briggss method and iron for colorimetric method of Orthophenanthroline (Audigie et al., 1978).
Magnesium, Potassium, Sodium, Calcium, Zinc, Copper and manganese were determined by spectrometry of atomic absorption, Perkin-Elmer, Model 1100 (BIPEA, 1976).
The dosage of total nitrogen contents of flours was analyzed by a Kjeldahl method with a Kjeltec digester and distilling (AOAC, 1990). One gram of the flour was used for analysis. Protein contents of the samples were calculated by multiplying the nitrogen content by 6.25 the conversion coefficient.
Lipid contents were determined by the method of extraction with Soxhlet using n-hexane (AOAC, 1990).
Total carbohydrates and total sugars were determined according to the method of Bertrand and Thomas (1910). Starch content was deducted by calculating the difference between total carbohydrates content and total sugars content.
Dietary fibres contents were determined by the gravimetric method of Prosky et al., 1984.
Amino acid analysis of weaning flour were measured out by liquid chromatography high performance in inverse phase (Colonne PTC RP-18, 220 mm long, 2.1 mm intern diameter and pré-colonne, Applera Corp, Fosters City, CA, USA). The sample is hydrolysed in vacuum at 150oC during 60 min in Pico-Tag station (Waters, Milford, MA, USA) with HCl 6 N at 1% phenol. Amino acids are separated in two buffer solution. Results are exploited thanks to application program Model 600 Data Analysis System.
Fatty acids are measured out by chromatography on gaseous phase. The sample (100 mg) is firstly methyled by BF3 , at 14% concentration in Methanol. The methyled esters are analyzed on a chromatograph on gaseous phase type HP 6890 series GC system. Fatty acids are identified thanks to fatty acids of reference.
Determination of the energy density in kilocalorie: The Energy Density (DE) was calculated with 4 kcal /g for carbohydrates, 4 kcal /g for proteins and 9 kcal /g for lipids according to Atwater and Benedict (1902) by the product of dry matter content of weaning mush.
DE =[9 x Lipids (%) + 4 x Proteins (%) + 4 x Carbohydrates (%)]
x DM (%)
RESULTS AND DISCUSSION
Chemical composition of simple flours: Chemical composition of Taro,
Pigeon pea and malted maize flours is shown in Table 1. Total
carbohydrates contents
were 82.6, 58.5 and 75.8% respectively Taro, Pigeon pea and malted maize flours.
Table 1: |
Chemical composition of Taro, Pigeon pea and malted maize
flours |
 |
Table 2: |
Dry matter and consistency of Taro gruel variation as a function
of quantity of Taro flour |
 |
Table 3: |
Dry matter and consistency of gruel prepared with a fixed
quantity of Taro (30 g) and variable proportions of malted maize |
 |
Table 4: |
Consistency and proteins content of gruel prepared from variable
proportions of Taro and Pigeon pea flours |
 |
Taro flour had a good source of carbohydrates. And proteins contents were 8.8%
for Taro, 26.5% Pigeon pea and 10.0% malted maize. Pigeon pea flour could be
used to enrich Taro flour in protein. Total ash contents were variable 4%, 4.5%
and 1.9% respectively for Taro, Pigeon pea and mated maize flours.
Dry contents and consistency of Taro mush according to Taro flour quantity
were represented in Table 2. We observed a considerable increase
in dry matter content (2 at 12.8% DM) as one goes along the quantity of Taro
flour increased. In the same time, the flow distance (mm/30 sec) of the gruel
measured using a Bostwick consistometer decreased to nullify. At 30 g of Taro
flour, the flow distance of Taro mush become null.
As soon as the proportions of the malted maize mixed increased, the fluidity of mush improved (10 at 130 mm / 30 sec) and accompanied by increase of dry matter content. It was a brought of 16.2% of malted maize which gave the best consistency (90 mm/ 30 sec) with 16.20% dry matter (Table 3).
Table 5: |
Elaboration of weaning flour constituted by Taro, Pigeon pea
and malted maize flours |
 |
Table 6: |
Nutritional value of weaning flour prepared by a combination
(58/18/14/10) of Taro, Pigeon pea, malted maize flours and sucrose |
 |
Different testing of formulation were carried out with the flours of Taro, malted maize, Pigeon pea and sugar (Table 5). Formulation 4 present 30.9% of dry matter content and 90 mm/30 sec of consistency of mush was the best formulation of infant flour. That formulation respected the criteria of WHO (1998).
Nutritional value of weaning flour formulated: The compound flour basis
of Taro, Pigeon pea and malted maize contained 70% of total carbohydrates, 15.7%
not sufficient to cover the young children needs (De Benoist, 1994). This deficit
could be filled by the minerals provided by the weaning flour. The consumption
of this infantile flour could protect the children from infantile malnutrition.
Further, the fatty acids content and amino acid profile of weaning were presented
respectively Table 7 and Table 8. Nine fatty
acids were identified with four fatty acids of short chain (caprylic acid, capric
acid, lauric acid and myristic acid); two of middle chain (palmitic acid and
palmitolein acid) and three of long chain (stearic acid, oleic acid and linoleic
acid). Linoleic acid was a polyunsaturated acid which had a beneficial effect
on the nervous system development (Bourre, 1996; Vancassel, 2004). Oleic acid
was not an essential fatty acid but it had a preventive role on cardiovascular
disease (Bouderlique et al., 1997). Fatty acids of weaning mush would
supply some calories necessary to young child to stay alive. Seven essential
amino acid werre obtained in weaning flour (Table 8). Threonine
(50,6 mg/g protein), valine (60 mg/g protein) and isoleucine (49, 7 mg/g protein)
were in the majority compared to the FAO/UNICEF reference protein (1986). The
lysine content collected from weaning flour (47.7mg /g protein) was lower than
values reported on FAO reference protein. These essential amino acids would
be useful of synthesis protein.
The infant flour mush had a high energy density (119 kcal/100 ml of mush) true
to international criteria of WHO/UNICEF (1998). This energy could be sufficient
to satisfy the energy needs of young children. Moreover, the supply of malted
maize has improved the consistency of mush flour infant. The children would
eat easily that gruel.
Table 7: |
Fatty acids of weaning flour prepared by a combinaison (58/18/14/10)
of Taro, Pigeon pea, malted maize flours and sucrose |
 |
Table 8: |
Essential Amino acids of weaning flour prepared by a combinaison
(58/18/14/10) of Taro, Pigeon pea, malted maize flours and sucrose |
 |
Table 9: |
Density energy of mush weaning prepared by a combinaison (58/18/14/10)
of Taro, Pigeon pea, malted maize flours and sucrose |
 |
Density energy of weaning mush = [(4. 6x9)+(70x4)+(15.7x4)]x30.
90% |
Conclusion: The results obtained from the analysis of weaning flour and weaning mush prepared from mixed flours showed that this infantile flour could cover the energys needs and nutriments needs of young children. The weaning flour prepared from mixed flours of Taro, Pigeon pea and malted maize contained some protein in important quantity, several minerals, essentials amino acids and fatty acids like linoleic acid. Therefore, the mush weaning had a good consistency, a good content of dry matter and high energy density sufficient for children.