The Effect of Fortification of processed Soya Flour with di-Methionine Hydroxy Analogue or di-Methionine on the Digestibility, Biological Value, And Net Protein Utilization of the Proteins as Studied in Children
Parthasarathy, H.N.; Doraiswamy, T.R.; Panemangalore, M.; Rao, M.N.; Chandrasekhar, B.S.; Swaminathan, M.; Sreenivasan, A.; Subrahmanyan, V.
Canadian Journal of Biochemistry 42: 377-384
(a) Eight girls aged 8 to 9 years, height from 114.3 to 127.7 cm, weight from 17.0 to 23.8 kg, from a low income group in Mysore who were accustomed to a diet of cereals, millets and legumes received in 3 meals daily a basal low-protein diet, adequate in other nutrients. The test was of five 10-day periods in which the children received the basal diet with supplements, respectively, of 41 g full-fat soya flour, or soya flour and 1.2 g DL-methionine per 16 g N, or soya flour with the same amount of DL-methionine hydroxy analogue, or 56.8 g skimmed milk powder, or no supplement. Faeces and urine were collected during the second 5 days of each period; daily excretion of creatinine ranged from 457 to 511 mg and of creatine from 49 to 75. Estimations were made of total N in diet, urine and faeces, and of the essential amino acid intake on each diet, also of digestibility coefficients, biological value (BV) and net protein utilization (NPU). Average daily excretions of N in urine and faeces on the low-protein diet were 1.05 and 0.7 g, respectively. For the supplemented diets, in the order given, intakes were 3.91, 4.11, 4.11 and 4.13 g, excretion in urine 2.25, 1.95, 2.05, and 1.68 g, excretion in faeces 1.36, 1.28, 1.32 and 1.26 g. True digestibility of the proteins was 84, 86.4, 85.8 and 87.1, and BV was 63.5, 74.9, 71.5 and 82.6. Protein intakes in g per kg were 1.19, 1.25, 1.25 and 1.26 and NPU was 0.63, 0.81, 0.77 and 0.90, compared with 0.6 and 0.9 as the minimum and optimum by FAO reference protein requirements and 0.64 and 0.96 as the minimum and optimum ideal protein requirements in g per kg. Supplementation of soya flour with methionine caused a marked increese in BV and NPU; the hydroxy analogue was less effective. Values for both were significantly less than for skimmed milk powder.