Comparative nutrient and anti-nutrient levels in commercial and formulated weaning mixtures

Transcription

1 BIOKEMISTRI 16(1):15-21 (June 2004) Printed in Nigeria 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 Kcal/kg energy, % proteins per 100g diet, and to reach and adequate level of NdpCal% of The proximate analysis of the diets showed that protein value ranged between %, carbohydrate %, lipid %, ash %, fibre %, and moisture %. The anti-nutritional factors analysis showed that percent loss in tannin content of % 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 * akaninworj@yahoo.com Tel:

2 INTRODUCTION Weaning starts at different times in different communities and its effects on infants of different socio- economic group also vary (1). Infants of more affluent socio- economic groups in industrialized and developing countries, in absence of breast feeding, suffer no nutritional disadvantage when fed properly constituted and hygienically prepared processed commercial formulas. However, the early abandonment of breast feeding by mothers among lower socioeconomic groups has often proved to be disastrous to infants (2). This is as a result of inadequate financial resources to purchase sufficient formula, and lack of knowledge and facilities to follow hygienic practices necessary to feed infants with breast milk replacements (3). The early discontinuance of breast feeding by mothers of low income groups in urban areas of most developing countries has therefore been a serious concern for some years (4,5). Breast milk on its own is sufficient for most infants until 4-6 months of age when they continue to grow satisfactorily (6,7). By the age of 6 months, most infants need additional foods, the purpose of which is to complement the breast milk and make certain that the young child continues to have enough energy and nutrients to grow normally (8). This goal is only achieved when these foods are prepared and fed to the infants under hygienic conditions and given in adequate proportions. Malnutrition (often in combination with infections) is the main factor responsible for the high infant mortality (9). Most of these infant morbidity and mortality could be prevented by improved nutrition, hygiene, housing and health care (10). There is urgent need for provision of weaning foods rich in protein, low cost and suitable for provision of infants nutritional needs. Unfortunately, this is lacking especially in rural parts of developing countries (11). However, it has been suggested that more than anything else, lack of information on the composition and utilization of the many protein and energy sources indigenous to the tropics is the major problem rather than a real shortage (12). It is in this view that this work has decided to look into the nutrient and antinutrient 16 composition of some low cost locally formulated weaning diets in a bid to use them for the alleviation of malnutrition. MATERIALS AND METHODS Sweet Potato Processing: (lpomoea batata L) The red skinned variety sweet potato purchased in Port Harcourt was used. The fresh roots were peeled, washed, cut into thin slices and dehydrated in a hot air oven at 70 0 C for 18 hours. The chips were then ground into flour using a hand mill, sieved through 710mm sieve and packed in plastic bags which were stored at 4 0 C until required for analysis. Processing of Bambara Groundnut (Voandzeia Subteranca Thonars) Undehauled seeds were purchased from Nsukka, freed from broken seeds, dust and stones and then washed with tap water after which they were soaked for 24 hours at room temperature. Dehulling by hand rubbing and drying in hot air oven at 70 o C for 20 hours were then carried out. The dried seeds were ground with a hand mill, sieved through a 710mm sieve and stored at 4 o C in plastic bags until required. Soya Beans Processing The soya beans ( Blessed soya beans and Chima soya beans ) processed by two different companies were purchased in Port Harcourt and the same method for bambara groundnut was applied except that the soaking time, drying temperature and drying time were 12 hours, 70 o C and 24 hours respectively. Corn Starch Processing White maize (Zea mays) purchased from Port Harcourt, Nigeria was used. The traditional method of Ogi preparation was used (13,14). The flour produced was packed in plastic bags and stored at 4 0 C. Vegetable Oil This was bought from Mile one Market, Port Harcourt, Nigeria Crayfish processing Dry crayfish was bought in Port Harcourt, further dried in the oven at 70 0 C for 2

3 hours and ground into powder. The powder was then used for analysis and diet formulation. Diet formulation The various flour preparations were autoclaved for 15 minutes at 121 o C before being used for diet formulation. Combinations were tested until the following criteria were met; total calories to approximate to Kcal/ 100g and NDpCal % to approximately %. High values of NDpCal% were avoided on the ground of cost, the amounts of the expensive protein supplements being kept to the minimum. A commercial maize-soya bean weaning formula (Nutrend) was used as the positive control diets while corn starch flour was used as the protein free or negative control diet. Table 1 shows the percentage composition of Experimental and Control diets. Proximate Analysis Analyses of all the processed food ingredients were conducted to be certain that ingredients were within the range of values anticipated. Similar analyses were carried out on each of the test diets, commercial soya bean flours and Nutrend to know the proximate moisture, ash, fibre, lipid, protein and carbohydrate contents. Tannin Determination Tannin was extracted with ethyl acetate using soxhlet apparatus for about 3 hours. The solvent was distilled off and the residue repeatedly washed with petroleum ether ( C) until no more colour was extracted. The residue was then dissolved in 10ml ethyl acetate. To 5ml of the tannin extract were added 5ml Folin-Denis reagent and 10ml of saturated sodium carbonate solution. This was diluted to 5ml with distilled water and left standing for one hour. The absorbance of the resulting blue complex was read at 725nm against a blank. This same treatment was given to the standard tannic acid and the concentration of tannin in the sample estimate from standard curve as described earlier (15). Phytic Acid Determination The method used (16) involved extraction of phytate and its conversion to ferric phytate, precipitation of ferric hydroxide from the ferric phytate, determination of iron in the 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) Sweet potato Corn starch Crayfish Vegetable oil Bambara groundnut Soya bean Nutrend 100 Total

4 RESULTS AND DISCUSSIONS The proximate nutrient values of processed flour samples and test diets as well as Nutrend are shown in tables 2 and 3. Crayfish had the highest protein value (66.72%) of all the samples of the raw materials followed by soya beans ( %) and bambara groundnut 22.42% (Table 2). The protein content of the diets increased with increasing amount of the legume flours: 12.03%, 15.09% and 17.50% for 25.50g, 36.50g and 47.00g bambara groundnut containing diets 1, 2 and 3 and 12.69%, 16.19% and 17.72% for 11.50g, 16.50g and 21.00g soya bean containing diets 4, 5 and 6. The preference for soya bean over bambara groundnut as a protein supplement is very evident (Table 2). Sweet potato bambara groundnut mixture and sweet potato soya bean however, contain similar protein values as the control diet Nutrend. The carbohydrate analysis (Table 2) presented sweat potato as containing the highest value (82.03%) followed by corn starch (70.31%) and bambara groundnut (61.72%). The soya bean however had similar carbohydrate content as the commercial diets. However the range of carbohydrate content in all test diets and Nutrend was between %. The Proteins Advisory Group (PAG) of the United Nations suggested an upper limit of 5.0% crude fibre in supplementary foods while Bressani et al (17) suggested a level of approximately 8% for weaning foods. However, the values obtained for these test diets and Nutrend ( %) fell within the recommended ranges for infants Antinutritional factors In addition, the processed samples, unprocessed bambara groundnut and soya beans flours were analysed for antinutrient levels to access the efficiency of the processing methods employed in detoxifying the antinutrients present in the raw materials. Results obtained are shown in Table 4 while the antinutrients found in both the formulated and control diets are shown in Table 5. Tannin Negative correlations between protein digestibility and tannin content in legumes have been reported (18). A low level of tannin in 18 legumes, and other food materials, is therefore recommended if they are to be consumed. Decortication has been found to result in the removal of % tannin. (19,20). Bressani et al (20) however reported apparent losses of % from raw to cooked beans when expressed as tannic acid. This study however presents a percent apparent loss in tannin content of 15.00% in soya beans and 51.22% in bambara groundnut within the range reported by (21).The tannin contents of soya beans used in his study were similar to values obtained for the commercial soya bean samples. This suggests that the processing techniques used in this study (soaking, dehulling, drying and autoclaving) were effective in reducing the tannin contents of the samples. The tannin contents of all the diets were however, also found to be low ( %). Though all the test diets and Nutrend had similar tannin contents, diets 1-4 and Nutrend had the least amounts (Table 5). Phytic acid Various reports have shown that soaking, prior to boiling results in loss of phytic acid from certain legumes and that the extent of the loss depended on the cooking solution or method used (22-24). However, Iyer et al (24) observed that presoaking and cooking by atmospheric boiling are more effective in reducing phytic acid than autoclaving. Though soaking in tap water prior to drying and autoclaving were adopted for processing the samples, percent apparent loss of 45.92% and % for bambara groundnut and soya bean flours respectively were achieved. These are consistent with the % apparent loss observed when peas and lentil were presoaked and boiled (24) and 76.82% when beans are presoaked and cooked (21), values obtained for the unprocessed and processed samples are shown in Table 4. The phytic acid content of the processed soya bean flour (70.72mg/100g) used in this study was found to be lower than the values for the two commercial soya bean fours (171.25mg and mg/100g). This could indicate the effectiveness of the method used. Phytic acid levels in all the test diets and control were found to be low ( mg/100g). However,

5 Table 2: Proximate nutrient values* of processed samples. Samples Protein Carbohydrate Fiber Moisture Lipid Ash Sweet potato 3.28± ± ± ± ± ±0.01 Corn starch 6.56± ± ± ± ± ±0.12 Crayfish 66.72± ± ± ± ± ±0.71 Bambara 22.42± ± ± ± ± ±0.58 groundnut Soya bean 45.83± ± ± ± ± ±0.41 Blessed 46.16± ± ± ± ± ±0.09 Soya bean Chima soya 46.16± ± ± ± ± ±0.03 bean * Values are mean ± SD of triplicate determinations. + Diets 1, 2 and 3 = Sweet Potato Bambara groundnut mixtures. Diets 4, 5 and 6 = Sweet Potato Soya bean mixtures. Table 3: Proximate nutrient values* of test diets and nutriend. Protein Carbohydrate Fibre Moisture Lipid Ash Diet ± ± ± ± ± ±0.43 Diet ± ± ± ± ± ±0.18 Diet ± ± ± ± ± ±0.18 Diet ± ± ± ± ± ±0.94 Diet ± ± ± ± ± ±0.09 Diet ± ± ± ± ± ±0.39 Diet ± ± ± ± ± ±0.08 (Corn starch) Diet 8 (Nutrend) 16.63± ± ± ± ± ±0.06 Table 4: Tannin and phytate contents of flour samples Samples Tannin (mg/100g) Phytate (mg/100g) Sweet potato Corn starch Unprocessed bambara groundnut Processed bambara groundnut Unprocessed soya beans Processed soya beans Chima soya beans Blessed soya beans

6 Table 5: Tannin and phytate contents test diets and nutrend. Samples Tannin Phytate 20 (mg/100g) (mg/100g) Diet Diet Diet Diet Diet Diet Diet 8 (Nutrend) Diet 3 contained the highest amount of phytic acid. In conclusion, the results obtained in this study place the test diets on a significant level with the commercial Nutrend used as control indicating that these test diets can effectively supplement Nutrend as weaning foods thus reducing the cost and availability of weaning foods to the less privileged prevalent in underdeveloped countries like Nigeria and other African countries. REFERENCES 1. Mokwena, C (1987) The use of fermented foods in child feeding in Botswana in lmproving young child feeding in eastern and Southern Africa:household-level food technology Proceedings of a workshop held in Nairoibi, Kenya, October. Alnwick, Moses and Schmidt. Pgs Government of the United Republic of Tanzania and United Nations Children s Fund (1990): Women and Children in Tanzania. A situation Analysis Pellet, P.L and Mamarbachi, D. (1978) Recommended proportions of foods in home made weaning mixtures. Ecol. Food. Nutr. 7: Jellife, D.B. (1971) Commerciogenic malnutrition: Time for a dialogue. Food Technol.25: Jellife, D.B. and Jellife E. F.P. (1975) Human Milk, nutrition and the world resource crisis. Science 188: Puffer, R.R and Serrano, C.V. (1973) Patterns of Mortality in Childhood. Paho Science Publication PAHO/WHO, Washington, D.C Abate, G and Yohannes, C. (1987) Traditional weaning practices in Ethiopia. In Improving young child feeding in Eastern and Southern Africa: Household Level food technology Proceedings of a workshop held in Nairobi, Kenya, October. Alnwick S. Moses and Schnidt (Eds) Bradley, J.; Baldwin, S. and Armstrong, H. (1987) Breast Feeding: A neglected household weaning food resource. In lmproving young child feeding in Eastern and Southern Africa: Household level food technology. Proceeding of a workshop held in Nairobi, Kenya, October, Alnwick, S Moses and Schmidt (Eds) WHO (1980) Six reports on the World Health Situation. Part One. Global analysis. Geneva. 10. Mclaren, D.S. (1977) Nutrition Planning: The Poverty of holism. Nature 267: Abbey, B.W and Nkanga, U.E (1988) Production of high quality weaning products from Maize Cowpea Crayfish mixtures. Nutr Rept. Int. 37: Nnayelugo, D.O. and Uwaegbute, A.C. (1987) Nutritive value and biological evaluation of processed Cowpea diets compared with local weaning foods in Nigeria. Nutr. Rept. Int. 22: Akinrele, I. A. (1970) Fermentation studies on maize during the preparation

7 of 9 traditional African starch cake food. J. Sci. Food Agric. 21: Umoh, l. B. and Fields, M.L. (1981) Fermentation of Corn for Nigerian Agidi. J. Food Sci. 46: Wheeler, E.L and Ferrell, R. E. (1971) A method for phytic acid determination in wheat and wheat fractions. Cereal Chem. 48: Ritchie, J.A.S. (1978) Manual on child development, family life and nutrition. ECA/FAO, United Nations, Addis Ababa. 17. Bressani, R; Elias, L. G; Wolzak, A; Hagerman, A. E. and Butler, l. G. (1983) Tannin in common beans. Methods of analysis and effects on protein quality. J. Food Sci. 48: Khokhar, S. and Chamhan, B. M. (1986) Antinutritional factors in Moth bean (Vigna Aconitifolia): Varietal differences and effects of method of domestic processing and cooking. J. Food Sci. 51: Bressani, R.; Elisa, L.G and Braham, J.E. (1982) Reduction of digestibility of legume Proteins by tannins. J. Plant Foods. 4: Honig. D.H; Wolf, W. J and Rackis, J.J (1984) Phytic acid and phosphorus content of various soya bean protein fractions. Cereal Chem. 61: Uzogara, S.G; Morton, l.d. and Daniel, J.W. (1990) Changes in some anti-nutrients of Cowpeas (Vigna Unguiculata) Processed with Kanwa alkaline salt. Plant Foods. Hum. Nutr. 40: Ologhobo, A.D. and Fetuga, B.L (1984) Distribution of Phosphorus and Phytate in some Nigerian Varieties of Legumes and some effects of Processing. J. Food Sci. 49: Manna, F.; Hussain, T.; Alli, I. and lgbal, P. (1987) Effect of Cooking on Phytic Acid Content and Nutritive Value of Pakistani Peas and Lentils. Food Chem. 2: Iyer, V; Salunkhe, D.k. Sathe, S.K and Rockland, L.B. (1980) Quick Cooking Beans (P. Vulgaris. L). Phytate, Oligosaccharides and anti-enzymes. Qual. Plant Foods. Human. Nutr. 30: