Formulation of Plant-based Weaning Diets and Assessment of their Nutritive Values and Health-promoting Potentials.
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It is believed that breast-fed infants may benefit from a gastrointestinal microflora that is predominated by Bifidobacteria and Lactobacilli. One important aspect of this is improved protection from certain gastrointestinal infections. Breast-feeding is therefore always encouraged, but is not always feasible due to inconvenience or other complications that necessitate lactose free or plant based formulae. Pro-, Pre-, and Symbiotic are thought to inhibit gastrointestinal tract (GIT) infections and/or stimulate the growth of Bifidobacteria and/or Lactobacilli, thus altering the gastrointestinal microflora. The purpose of this study was to produce nutritionally balanced, anti-nutrient free formula from plant sources for the dietary management of Protein Energy Malnutrition, lactose intolerance, galactosemia and food allergy. Because of the attendant GIT infections in these cases, the prebiotic, growth and health promoting and microflora modulating potentials of the unstirred batch culture of processed plant materials; stirred batch culture of formulated blends A, B, C & D and infant gut simulating models of the best two formulae B and C were investigated. The bacteria were enumerated using culture independent fluorescence in situ hybridization, FISH. Weaning blends, formulated in a 60-70% cereal to 30-40% legume/nuts combination using maize, tiger-nuts, groundnut and melon were prepared by traditional processing methods of natural fermentation, germination, roasting, and steaming using Isomil (a lactose free soya based formula) and unprocessed plant materials as controls. Germinated seeds consistently and significantly (p<0.02) had low viscosities compared to other processing methods. The viscosities of raw and germinated maize flour were 1341cp and 195cp respectively, a decrease of greater than 400%. Germination also produced finer flour. This study established that minimum steeping for each grain, followed by 72hrs germination at ambient temperature was optimum for malting of the grains. This yielded malted grains with higher protein and starch digestibilities with minimum loss in dry matter. Natural fermentation on the other hand was found to increase the viscosity of maize flour to 1477cp compared to 1341cp for raw maize (an increase of 10%). Presence of 1-1.5% w/w of organic acids (lactate, acetate, and propionate) caused the characteristic flavor and aroma and significantly inhibits the growth of microbes and confers microbial safety. Qualitative analysis for the presence of anthocyanins, flavonoids, polyphenols, saponins, phytobatanins, tannins and betacyanin confirmed the presence of all except betacyanin in all raw materials. Roasting was found to decrease the phytic acid content from between 81.82% in groundnut to 93.02% in tigernut; Tannin was decreased from between 69.30% in tigernut to 83.97% in maize and Trypsin inhibitors from between 37.73% in groundnut to 54.06% in tigernut. Steaming decreased phytic acid content by between 76.19% in tigernut and 84.70% in maize. Tannin was decreased from between 63.98% in maize and 73.95% in tigernut; and trypsin inhibitors from between 39.72% in melon to 69.87% in maize. Fermenting decreased the phytic acid content from between 69.05% in tigernut to 87.68% in maize; tannin from between 72.03% in groundnut to 80.16% in maize; and trypsin inhibitors from between 39.12% in melon to 55.41% in tigernut. Germination (the 3days spout) decreased the phytic acid content from between 64.28% in tigernut and 82.43% in maize; tannin from between 53.95% in tigernut and 80.56% in maize; and trypsin inhibitors from between 36.48% in groundnut and 47.79% in tigernut. Roasting was more effective in decreasing the phytic acid and tannin contents while steaming was more effective in removing the trypsin inhibitors. Unstirred batch culture study of the prebiotic potentials of all the processed plant materials showed their bifidogenic potentials, comparable to that of lactose, the predominant oligosaccharide in breast milk. Fermented corn, roasted corn and steamed groundnut and corn gave significantly higher values of Bifidobacterium counts than lactose after 24 hrs of fermentation. In the stirred batch culture of the weaning formulae A, B, C & D, only B & C gave significantly (p<0.05) higher counts of Bifidobacterium than Isomil, particularly after 6 hours of fermentation (T6).The growth and health promoting effects of Formulae B and C on infant gut microflora showed significant changes in the populations of Bifidobacterium and Lactobacillus. The total bacterial and Bacteroides counts remained constant within 0.5 log values in both vessels. No significant antibacterial effect on Clostridium proliferation was observed. B & C however, gave significant decrease in E. coli population compared to Isomil. Both short- & branched- chain fatty acids were produced as fermentation end product, their concentration being much higher in vessel 1 (V1 representing proximal colon) than in vessel 2 (V2, distal colon). Butyrate was the predominant acid, contrary to previous findings. Challenge with Enteropathogenic Escherichia coli (EPEC 0127:H6) at steady state (Ts) showed significant (p<0.05) increase in E. coli population in all vessels, decreasing to basal values by day 6 (D6) after infection for Formulae B & C. The population in Isomil vessels remained relatively high. Formulae B & C thus exhibited antibacterial and anti-diarrheal effects. The proximate, energy densities, mineral, amino acids, antinutrient and microbial compositions of the formulated blends were within the recommended values. Calcium, lysine and tryptophan however, need to be added. The protein intake and weight gain of rats fed Formulae B, C and Isomil were comparable but significantly (p<0.05) lower than that of rats fed the casein diet. The Nitrogen Efficiency Ratio (NER), Feed Efficiency Ratio (FER), Protein Efficiency Ratio (PER) and Relative Protein Efficiency Ratio (rPER) of all the diets followed the same pattern. The Protein Efficiency Ratio (PER) values for all the formulae ranged from 2.24 to 2.95 and were higher than the minimum value (2.1) recommended for such foods by the Protein Advisory Group. The protein qualities in terms of Biological value (BV), Net Protein Utilisation (NPU) and True Digestibility (TD) of the formulae were similar to that of casein, indicating that absorbed nitrogen from the diets was well utilized like that of casein.
A Thesis Submitted to the School of Postgraduate Studies, University of Lagos.
Breast-feeding , Dietary Management , Nutritive Values , Research Subject Categories::MEDICINE::Chemistry::Biochemistry
Dawodu, A.O (2012), Formulation of Plant-based Weaning Diets and Assessment of their Nutritive Values and Health-promoting Potentials. A Thesis Submitted to University of Lagos School of Postgraduate Studies Phd Thesis and Dissertation, 282pp.