MATERIALS AND METHODS

Fifty packets (400 g each) of BBF were kindly donated to us by the, Bennimix factory in Bo, the second capital city of Sierra Leone. The Cerelac weaning food was purchased from a supermarket in Wuxi, People’s Republic of China. They were kept under the conditions as stipulated by the concerned manufacturers.

The chemicals and reagents used were of analytical and food grade quality obtained from the chemical store of Jiangnan University Wuxi, PR China, manufactured by Sinopharm Chemical Reagent Co., Ltd. (SCRC) Shanghai PR China.

BBF is produced according to the flow chart (Fig. 1). The flow chart was given to us and reproduced with the kind permission of the Bennimix factory, while Cerelac flow chart has been shown in many works that are related to weaning foods (Sefa-Dedeh et al., 2003). Cerelac was used to compare with BBF because is a cereal-based food internationally accepted by many countries in the world as weaning food for the age bracket prescribed for BBF also (1/2-5 year). Moreover Cerelac is one of the weaning food sole in Sierra Leone.

This research was conducted in the State Key Laboratory of the School Food Science and Technology, Jiangnan University, Wuxi, People’s Republic of China between March to June 2007.

Chemical Analysis
BBF was analyzed for moisture, ash content, protein, dietary fibre using the standard method of AOAC (1995). Total lipids, ether extract and carbohydrate contents were determined using AACC (1998). While the determination of vitamins: thiamine, nacine, Vit B12, Vit D Vit A and Vit. C was done according to the Association of Vitamins Chemists as described by Ranganna (1986).

The determination of some minerals (calcium, iron, copper, potassium lead) for both BBF and Cerelac was done with Varian Flame Atomic Absorption Spectrophotometric (SPECTRAA 220, USA).

Fig. 1:	The production flow chart of Bennimix baby food

BBF was analyzed for amino acids; the BBF was dissolved in 3.5% 5-Aulfosalicylic Acid (SSA). After filtration and centrifugation, the supernatants were submitted to online derivatization by o-Phthaldialdehyde (OPA) and reversed phase high Performance Liquid Chromatography (RP-HPLC) analysis in an Agilent 1100 (Agilent Technologies, Palo Alto, CA 94306, USA) assembly system using a Zorbax 80A C₁₈ column (4.6 idx180 mm) as by the conditions set by the equipment manufacturer. The amount of asparagine and glutamine was determined as aspartic acid and glutamic acids, respectively.

The carbohydrate content was obtained by difference according to the AOAC (1995) method. The total energy (kcal) was calculated by multiplying the digestible carbohydrate and protein contents by four and the fat content by nine using AOAC (1995) method.

Functional Properties
Bulk density for BBF and Cerelac, was determined by the method of Wang and Kinsella (1976). The final materials tested were expresses as g mL^-1. For water absorption, it was tested by the method described by Cegla et al. (1977), 6 g of both BBF and Cerelac were weighed in a 100 mL beaker separately. Water was pipetted into each beaker and the amount of water was recorded. The slurries were carefully stirred and allowed to equilibrate for one hour at 26°C. After the water has been completely absorbed, the samples were treated with 10 mL water portions with 10 min interval before visual observation. The volume that gave a complete absorption of water was recorded. The apparent viscosity of BBF and Cerelac was done according to Quinn and Beuchat (1975). The two samples (BBF and Cerelac) were stirred into cold water and mixed into a uniform mixture to form slurries; the slurries were put in a boiling water bath (75°C) and constantly stirred until they boiled and were left for a period of three minutes. The samples were then removed and cooled down at room temperature (23-25°C) and the viscosity was calculated by measuring with a Brookfield Synchro-electric Viscometer (BSEV-2230-Japan), using RVT Spindle No. 4 at a constant speed of 100 rpm. The conversion was done into cps units.

For the pasting properties, the two samples (BBF and Cerelac) their slurries were heated from 40 to 92.5°C at the rate of 3°C min^-1, maintained at 92.5°C for 15 min and then cooled to 40°C at the same rate and their pasting properties were determined by a Rapid Visco Analyzer (RVA-4, Newport Scientific, Warriewood, USA) this was done to observe how the two products behaves when subjected to heat and see their spoonability. All the measurements were triplicated.

Sensory Evaluation of the Bennimix Food
The sensory evaluations of the boiled BBF and Cerelac were carried out to determine and assess its organoleptic characteristics according to Duncan (2005). A nine-member panel of judges consisting lecturers, students and laboratory assistants in the sensory and evaluation department of the Jiangnan University, Wuxi, PR China was constituted. The rationale for that selection was because of their experiences in weaning food properties that is formulated from cereals and legumes and getting parents to allow their children to take part was difficult as the food has never been accessed for nutritional composition. Nonetheless another study on the acceptability of the food by mothers and infant is on the way after knowing its nutritional composition. The members of the panel were told to rate both the BBF porridge that has been prepared for fifteen to twenty minutes which is the recommended time that is stipulated for it to be ready for consumption and Cerelac since it is an instant food, hot water was added and stirred it to give the gruel that is fed to children. The rating was done for colour, texture, taste, consistency, appearance and aroma (Flavour) The rating was presented on a 9-point Hedonic scale ranging from 9 = like extremely to 1 = dislike extremely by using Score Card Method. The evaluation was done according to the method given by Amerine et al. (1965). All the figures obtained were values represent means of three replicates from the panelists.

Statistical Analysis
The results were subjected to statistical analysis of variance (ANOVA), using a Statistical Analysis System (SAS, 2002). The Significant of difference between means were determined by Duncan’s Multiple Rang Test (DMRT), where p<0.05 was considered for significant difference.

RESULTS AND DISCUSSION

The nutritional composition of BBF is shown in (Table 1). It reveals some moderate differences with the Cerelac food used to compare with. The protein was less than the Cerelac but the difference was not significant (p<0.05). But the raw materials of the BBF, one could have thought the protein content will be very high because they used both sesame and cowpea in the production of BBF. Those two crops are high in protein content. The result was an indication that during the processing stages that was where the protein was denatured because of the excessive use of heat and protein is not stable to high heat (Mensa-Wilmot et al., 2001). The production flow chart of the BBF did not indicate at any point where defatting of the sesame seeds is taking place and the removal of the seed coat also for both the cowpea and sesame (Fig. 1). It has been proved that defatted and dehulled sesame seed have higher protein content than not defatted and not dehulled (Sato, 2003).

Both the carbohydrate and fat were higher as compared to Cerelac and the differences were significant (p<0.05). The moisture content was also higher than the Cerelac; the difference was also significant (p<0.05). Our result with regards to the above properties corroborated the findings of Dorosko and Rollins (2003). This might not be good for the BBF if it is to have a stable shelf life. The BBF has some minerals like iron, calcium, copper, potassium, lead, as 10.5, 230, 123, 78, 0.91, (mg/100 g), respectively), Cerelac has its own minerals as 15.9, 570, 174, 102, 0.05 (mg/100 g), respectively (Table 1). The above mineral contents for BBF were enough for the age of infants the food is meant for consumption. Present result corroborated the findings of Dorosko and Rollins (2003), they studied infant formula prepared by rural and semi-rural women in South Africa.

Table 1:	Nutritional composition of BBF as compared to cerelac food
Units in bracket indicate nutrient density per gram of the sample; Values are means±SD of three independent determinations; =Protein %X4/total energy of formulation

Table 2:	Amino acid profiles of BBF
Values are means±SD of three independent determinations; b: Suggested profile of essential amino aid requirements for adults (FAO/WHO, 1990); c: Methionine+Cystine

For the amino acids as compared with the suggested pattern of requirement by FAO/WHO for human beings particularly infants (FAO/WHO, 1990) approved amount for the two categories (0-1 and 2-5 years) of age of children, almost all of the amino acids for children below one year is less in the BBF, but the difference was not significant (p<0.05) for some of them while almost all of its amino acids were in line or a little above the approved amount for children above one year to five years as shown in Table 2. The essential amino acids were present and in higher amount, their amounts were significant (p<0.05) The EAA were isoleucine, leucine, lysine, threonine, valine tryptophan, phenylalanine and methionine with cystine, 29, 80, 61, 44, 30, 18, 35 and 54 (mg g^-1 protein), respectively. According to our results, Valine is less than the recommended amount by FAO/WHO (1990) expert report. Some of the results of BBF of EAA were in accordance to Mensa-Wilmot et al. (2001) with the exception of Valine and Isoleucine which were in lower amount than there results.

Fig. 2:	Amilograph pasting characteristics of extruded cerelac and BBF

They investigated the protein quality evaluation of cowpea-based extrusion cooked cereal/legume weaning mixtures. However, the BBF is produced to cover the period from 6-24 months according to the producer’s instructions in the sachet the food is packeted for sales. The child for a healthy growth needs these amino acids. One essential amino acid that is usually absent in infant food produced from just cereals is methionine and cystine, but the amount of methionine and cystine in BBF was observed to be in high amount (54 mg gN^-1), however, those two amino acids are always high in sesame seeds (Lopez et al., 2003), that was why the BBF has that amount.

When the two samples were analyzed for their pasting properties by heating them, the difference was not significant (p<0.05), it was observed that at 10 min the Cerelac exhibited higher past of (150RVU) it kept on increasing gradually up to 20 min and the BBF also increased as the time was increased though below the line of Cerelac. At 20 min Cerelac was (230RVU) while BBF (225RVU) when the temperature was 80°C (Fig. 2). After that, the two samples dropped, when the heating time was prolonged between 30-35 min the two samples fell on the same line until when the time was extended to 40 min then the BBF gradually increased more than the Cerelac. The increased of pasting observed from BBF was observed also when the viscosity of the BBF was analyzed. The viscosity was high as the pasting properties of the BBF as these two always correlate.

From the results obtained it was observed that BBF was able to have that pasting properties even at high temperatures (88 and 96°C) the pasting was (250 and 280 RVU, respectively) which is still within an acceptable range for infant formula. As it has been reported that most of the food items particularly infant foods prepared within the range of 80°C and above which is considered as high temperature, will exhibit a pasting property that will be good for infant consumption (Kulkarni et al., 1991). At the above temperatures (88 and 96°C) BBF exhibited a gradual increase as the time was also increased; this was observed because solution conditions, such as time, ionic strength and temperature affect pasting of food made from cereals and legumes. The high temperature helped to denature the protein and exposes more sites of the present starch granules that are in that food, it can increases the pasting properties. It was reported that the pasting properties of globular proteins (which is mostly found in sesame and peas) generally decrease as time and temperature are decreased and increase when the two are increased (Modler and Emmons, 1977). The high pasting properties were actually dependent on the high protein and carbohydrate concentrate in sesame seed, cowpea and rice respectively which are the main raw materials of BBF. The formation of paste composed of swollen starch granules dispersed in the heated solution also increases the pasting properties of infant foods (Genovese and Rao, 2003). Present result was in accordance with the results of Sandhu et al. (2007) they compared a native and acid thinned normal and waxy corn starches and studied the physicochemical, thermal, morphological and pasting properties.

The pasting properties was studied also to see how appropriate the food will be for the child but according to the results BBF shows good pasting properties as the results were within accepted range which will not stick along the throat of the child while eating it.

Functional Properties
Some of the functional properties investigated in BBF revealed to be higher than those of Cerelac as shown in Table 3. The bulk density of BBF was higher than the one for Cerelac and the difference was significant (p<0.05). It was attributed to the high presence of carbohydrate in the food. That indication is highly correlated with the high viscosity and pasting of BBF because when the food absorbed more water, it will lead the food to have a thick gel that gives the high viscosity of the food (Nout and Ngoddy, 1997), which is really not good for young babies who are consumers of BBF, but this again depends on several molecular properties such as size, shape, flexibility and hydration of the protein. Because solutions of randomly coiled polymers displays greater viscosity. Also the ability of the protein and carbohydrate to absorb water and swell affects its viscosity and this can be seen in food containing protein and carbohydrate (Pérez-Conesa et al., 2002) which BBF is not an exception.

The water absorption capacity was higher in BBF than Cerelac. It was due to the high carbohydrate content also which was observed in BBF. As high carbohydrate increases the water absorption capacity of most food systems (Dorosko and Rollins, 2003).

The apparent viscosity was also higher than cerelac and the difference was significant (p<0.05). The results of the functional properties of BBF were in accordance with the ones reported by Kulkarni et al. (1991) they studied sorghum malted-based weaning food formulation: Preparation, functional properties and nutritive value. The aspect of high viscosity could be corrected by changing the processing to fermenting the raw materials or germinate the rice or add α-amylase to help in the degradation of the carbohydrate to reduce the viscosity as these have been reported in many studies in cereals and legumes combination (Simango, 1997).

Sensory Evaluation
The organoleptic properties of BBF were (Table 4). For flavour, it was rated good to very good while Cerelac was rated in that area as fair to good. The flavour of the BBF was rated good to very good by the panelists while cerelac was rated fair to good.

Table 3:	Some functional properties of BBF and cerelac
a: Values represent means of three replicates±standard deviation; means values with different letter(s) in the same column are significant at level (p<0.05)

Table 4:	Sensory evaluation quality attributes of porridges of Bennimix food and cerelac
HS = Hedonic Scale, SCM = Score Card Method

Since BBF has sesame as part of it raw materials it is the one that responsible for the appealing flavor that made the panelists to rate it higher than the cerelac, as sesame under goes roasting during the process of the production of BBF that gives the food that outstanding flavour, because lots of researches have reported that roasted sesame seeds can give different aroma that are appealing to people (Schieberle et al., 1996). But for appearance, texture and colour of BBF were rated fair to good. It is because the seed coats of the various raw materials (Sesame, cowpea) were not removed and these two material seed coats are black or brown in the case of sesame seed while cowpea has black spot. For the taste, BBF was rated higher than cerelac; sugar is added to BBF during the production which is the factor that is responsible for the sweet taste of BBF. Present results supported the findings of Ukhun and Ukpebor (1991). They studied the production of instant plantain flour, sensory evaluation and physico-chemical changes during storage. The type of sugar should be investigated to know if it is appropriate and to the required amount for infants. For the overall acceptability BBF was rated as liked moderately while Cerelac rated good to very good. This could be improved if the raw materials are treated with all the precautions they need to bring out a very good product for infants.

CONCLUSIONS

The physicochemical properties of BBF were investigated and compared its properties with those of Cerelac. According to the results some of the nutritional properties of BBF were observed to be lower than Cerelac but the difference was not significant (p<0.05), but some were higher and the difference were significant (p<0.05). The amino acids, BBF was lower in the category of age of 0-1 year as stipulated by FAO/WHO expert report but higher in the second category (2-5 years). The functional properties of BBF were observed to have good attributes as compared to Cerelac and the difference was significant (p<0.05). Sensory qualities, flavour and taste were rated higher than Cerelac however the others were rated lower than Cerelac.

BBF was successfully analyzed and compared with Cerelac which was used as a standard product.

ACKNOWLEDGMENTS

We will like to extend our profound gratitude to the Bennimix factory in Sierra Leone for given us the permission to investigate their product and providing us BBF for the purpose of analyzing it for this work. And also the government of Sierra Leone for the thought that, it is necessary to scientifically investigate the physicochemical properties of the food and to the Chinese Government for the financial support given to us to do the analysis in one of their leading key lab in a renowned food science university. Lastly our thanks to the University chemical store and the analysis centre for helping us to come out with reliable results in our findings.