An international journal published by the BIOKEMISTRI 16(1):15-21 (June 2004) Printed in Nigeria N ig erian S oc iety for E x perim ental B iolog y Comparative nutrient and anti-nutrient levels in commercial and formulated weaning mixtures Joyce O. AKANINWOR* and Patience N. OKECHUKWU Department of Biochemistry, University of Port Harcourt, Port Harcourt, Nigeria. Received 4 February 2003 MS/No BKM/2003/006, © 2004 Nigerian Society for Experimental Biology. All rights reserved. -------------------------------------------------------------------------------------------------------------------------------------------- Abstract The proximate and antinutrient analyses of six diets based on processed sweet potato- crayfish- soyabean/ bambara groundnut mixtures were determined using ‘Nutrend’ as standard. Values for two sources of commercial processed soya bean flours used as protein supplements for infants and children in Nigeria were also investigated. Tannin (as tannic acid equivalent) and phytic acid contents of the ingredients and diets were also determined. Ratios of feed ingredients were formulated to provide 352-391 Kcal/kg energy, 12.03 -17.72% proteins per 100g diet, and to reach and adequate level of NdpCal% of 6.54 -8.02. The proximate analysis of the diets showed that protein value ranged between 7.88 -17.72%, carbohydrate 60.90 – 69.53%, lipid 2.02 -6.49%, ash 1.70 – 5.20%, fibre 0.61 -6.59%, and moisture 7.10 -9 .15%. The anti-nutritional factors analysis showed that percent loss in tannin content of 15. 00% and 51.22% in soya beans and bambara groundnut respectively were achieved and percent apparent loss of phytic acid content of 74.78% and 45.92% for soya beans and bambara groundnut respectively were also achieved. The diets that contained sweet potato – bambara groundnut mixture and sweet potato – soya bean mixture were similar to Nutrend (P> 0.05) in enriched nutrient content while diets containing tannin and phytate levels reduced significantly (P <0.05) to values close to that of Nutrend. These diets can effectively substitute for Nutrend based on their analyzed nutrient and anti-nutrient values. --------------------------------------------------------------------------------------------------------------------- *E-mail: [email protected] Tel: 08033405300 15 INTRODUCTION composition of some low cost locally formulated weaning diets in a bid to use them for the Weaning starts at different times in alleviation of malnutrition. different communities and its effects on infants of different socio- economic group also vary (1). MATERIALS AND METHODS Infants of more affluent socio- economic groups Sweet Potato Processing: (lpomoea batata L) in industrialized and developing countries, in The red skinned variety sweet potato absence of breast feeding, suffer no nutritional purchased in Port Harcourt was used. The fresh disadvantage when fed properly constituted and roots were peeled, washed, cut into thin slices hygienically prepared processed commercial 0 and dehydrated in a hot air oven at 70 C for 18 formulas. However, the early abandonment of hours. The chips were then ground into flour breast feeding by mothers among lower socio- using a hand mill, sieved through 710mm sieve economic groups has often proved to be and packed in plastic bags which were stored at disastrous to infants (2). This is as a result of 0 4 C until required for analysis. inadequate financial resources to purchase sufficient formula, and lack of knowledge and Processing of Bambara Groundnut (Voandzeia facilities to follow hygienic practices necessary Subteranca Thonars) to feed infants with breast milk replacements (3). The early discontinuance of breast feeding Undehauled seeds were purchased from by mothers of low income groups in urban areas Nsukka, freed from broken seeds, dust and of most developing countries has therefore been stones and then washed with tap water after a serious concern for some years (4,5). which they were soaked for 24 hours at room temperature. Dehulling by hand rubbing and Breast milk on its own is sufficient for o most infants until 4-6 months of age when they drying in hot air oven at 70 C for 20 hours were continue to grow satisfactorily (6,7). By the age then carried out. The dried seeds were ground with a hand mill, sieved through a 710mm sieve of 6 months, most infants need additional foods, o the purpose of which is to complement the and stored at 4 C in plastic bags until required. breast milk and make certain that the young child continues to have enough energy and Soya Beans Processing nutrients to grow normally (8). This goal is only The soya beans (“Blessed soya beans” achieved when these foods are prepared and fed and “Chima soya beans”) processed by two to the infants under hygienic conditions and different companies were purchased in Port given in adequate proportions. Harcourt and the same method for bambara Malnutrition (often in combination with groundnut was applied except that the soaking infections) is the main factor responsible for the time, drying temperature and drying time were o high infant mortality (9). Most of these infant 12 hours, 70 C and 24 hours respectively. morbidity and mortality could be prevented by improved nutrition, hygiene, housing and health Corn Starch Processing care (10). White maize (Zea mays) purchased from There is urgent need for provision of Port Harcourt, Nigeria was used. The traditional weaning foods rich in protein, low cost and method of “Ogi” preparation was used (13,14). suitable for provision of infants nutritional The flour produced was packed in plastic bags 0 needs. Unfortunately, this is lacking especially and stored at 4 C. in rural parts of developing countries (11). However, it has been suggested that Vegetable Oil more than anything else, lack of information on This was bought from Mile one Market, Port the composition and utilization of the many Harcourt, Nigeria protein and energy sources indigenous to the tropics is the major problem rather than a real Crayfish processing shortage (12). It is in this view that this work has Dry crayfish was bought in Port decided to look into the nutrient and antinutrient Harcourt, further dried in the oven at 70 0C for 2 16 hours and ground into powder. The powder was moisture, ash, fibre, lipid, protein and then used for analysis and diet formulation. carbohydrate contents. Diet formulation Tannin Determination The various flour preparations were Tannin was extracted with ethyl acetate autoclaved for 15 minutes at 121o C before being using soxhlet apparatus for about 3 hours. The used for diet formulation. Combinations were solvent was distilled off and the residue tested until the following criteria were met; total repeatedly washed with petroleum ether (40–60 calories to approximate to 353 – 391 Kcal/ 100g 0C) until no more colour was extracted. The and NDpCal % to approximately 6.50-8.19 %. residue was then dissolved in 10ml ethyl acetate. High values of NDpCal% were avoided on the To 5ml of the tannin extract were added 5ml ground of cost, the amounts of the expensive Folin-Denis reagent and 10ml of saturated protein supplements being kept to the minimum. sodium carbonate solution. This was diluted to A commercial maize-soya bean weaning 5ml with distilled water and left standing for one formula (Nutrend) was used as the positive hour. The absorbance of the resulting blue control diets while corn starch flour was used as complex was read at 725nm against a blank. the protein free or negative control diet. Table 1 This same treatment was given to the standard shows the percentage composition of tannic acid and the concentration of tannin in the Experimental and Control diets. sample estimate from standard curve as described earlier (15). Proximate Analysis Analyses of all the processed food Phytic Acid Determination ingredients were conducted to be certain that The method used (16) involved ingredients were within the range of values extraction of phytate and its conversion to ferric anticipated. Similar analyses were carried out on phytate, precipitation of ferric hydroxide from each of the test diets, commercial soya bean the ferric phytate, determination of iron in the flours and Nutrend to know the proximate sample and calculation of phytic acid from the resulting iron. Table 1: Percentage composition of the experimental and control diets. Ingredients Diets (%) (g/100g Diet) 1 2 3 4 5 6 7 8 Sweet potato 54.50 43.50 33.00 68.50 53.50 59.00 - - Corn starch 10.00 10.00 10.00 10.00 10.00 10.00 98.00 - Crayfish 8.00 8.00 8.00 8.00 8.00 8.00 - - Vegetable oil 2.00 2.00 2.00 2.00 2.00 2.00 2.00 - Bambara groundnut 25.50 36.50 47.00 - - - - - Soya bean - - - 11.50 16.50 21.00 - - Nutrend 100 Total 100 100 100 100 100 100 100 100 17 RESULTS AND DISCUSSIONS legumes, and other food materials, is therefore recommended if they are to be consumed. The proximate nutrient values of Decortication has been found to result in the processed flour samples and test diets as well as removal of 83–97 % tannin. (19,20). Bressani et Nutrend are shown in tables 2 and 3. al (20) however reported apparent losses of 20– Crayfish had the highest protein value (66.72%) 39 % from raw to cooked beans when expressed of all the samples of the raw materials followed as tannic acid. by soya beans (45.83 – 46. 16%) and bambara groundnut 22.42% (Table 2). This study however presents a percent The protein content of the diets apparent loss in tannin content of 15.00% in increased with increasing amount of the legume soya beans and 51.22% in bambara groundnut flours: 12.03%, 15.09% and 17.50% for 25.50g, within the range reported by (21).The tannin 36.50g and 47.00g bambara groundnut – contents of soya beans used in his study were containing diets 1, 2 and 3 and 12.69%, 16.19% similar to values obtained for the commercial and 17.72% for 11.50g, 16.50g and 21.00g soya soya bean samples.