Nutrient Composition, Amino Acid Profile and Anti-nutritional Factors of Nixtamalized Maize Flour Supplemented with Sprouted Soybean Flour

The high dependence on maize as a staple food in Tropical Africa, coupled with its low nutritive value necessitate investigation on how to improve the nutritional value of maize based foods. The present study was aimed at assessing the effect of supplementing nixtamalized maize flour with sprouted soy bean flour on the proximate composition, mineral content, amino acid profile and anti-nutritional factors in the blends. Nixtamalized maize flour was prepared by cooking maize grains in 1% unripe plantain peel ash solution (pH 10.2), steeped in the cooked solution for 15 h, washed, dried and milled into flour. The flour was supplemented with 0, 10, 20, 30 and 40% sprouted soy flour and analyzed for the aforementioned parameters. The results showed that protein, fat, ash, crude fibre and caloric value increased with increase in soy flour supplementation ranging from 9.26–22.57%, 4.51–10.53%, 1.38–2.06%, 2.14–2.39% and 408.47–434.85 kcal/100 g respectively while carbohydrate decreased from 82.71 – 62.45%. Potassium, calcium, magnesium and zinc contents increased from 267.58 – 286.35mg/100g, 126.93 – 161.03 mg/100 g, 135.71 – 163.81 mg/100 g and 4.52 – 4.85 mg/100 g respectively with soy flour addition. The total amino acids and total essential amino acids increased from 70.55 g/100 g protein and 30.54 g/100 g protein for the control to 87.97 g/100 g protein and 38.98 g/100 g protein for the 40% soy flour supplemented blends respectively. Limiting essential amino acids in both flours were significantly (P = 0.5) improved as a result of soy flour supplementation. Majority of essential amino acid chemical scores were above 100% except for lysine (51.03–66.38%), tryptophan (67.27–95.46%) and threonine (80.88 – 99.12%). Soy flour supplemented blends had higher phytate, trypsin inhibitor and tannin contents than the control sample but their values were low and may not have serious effect on nutrient bioavailability. The study clearly shows that nutritional value of nixtamalized maize flour can be improved by supplementing it with sprouted soy flour.

Fibrinolytic protease production by new Streptomyces sp: DPUA 1576 from Amazon lichens

Background Streptomyces sp. DPUA 1576 from Amazon lichens was studied to protease and fibrinolytic production. A 2² factorial experimental design was applied to optimize its protease enzyme production using two independent variables, namely soybean flour and glucose concentrations. Results The optimal conditions to obtain high protease production (83.42 U/mL) were 1.26% soybean flour and 1.23% glucose concentration. A polynomial model was fitted to correlate the relationship between the two variables and protease activity. In relation to fibrinolytic activity, the highest activity of 706.5 mm² was obtained at 1.7% soybean flour and 1.0% glucose concentration, which was 33% higher than plasmin. Fibrinolytic production was not optimized in the studied conditions. Conclusions These results show that the optimization of the culture medium can enhance protease production, thus becoming a good process for further research. In addition, Streptomyces sp. DPUA 1576, isolated from Amazon lichens, might be a potential strain for fibrinolytic protease production.

Heat-treated hull flour does not affect iron bioavailability in rats / Farinha de soja com casca tratada termicamente

In this study the chemical composition and iron bioavailability of hull and hull-less soybean flour from the new cultivar UFVTN 105AP was evaluated. The hemoglobin depletion-repletion method was used in Wistar rats. Soybean hull flour presented 37% more total dietary fiber and higher content of iron than hull-less soybean flour. The phytate:iron molar ratio, however, was 2-fold lower in the soybean hull flour in compared to the hull-less soybean flour. Animals fed soybean hull flour presented hemoglobin gains similar to those of the control diet group (p>0.05). The Relative Biological Values of hull and hull-less soybean flour were 68.5% and 67.1%, respectively, compared to the control group. Heat-treated soybean hull flour (150ºC/30 minutes) showed high content of iron and low phytate, which favors the iron bioavailability. Thus, the soybean hull flour is a better source of dietary fiber and iron than hull-less soybean flour at comparable bioavailabilities.

Neste estudo foram avaliadas a composição química e a biodisponibilidade de ferro das farinhas de soja com e sem casca do novo cultivar UFVTN 105AP. O método usado foi de depleção-repleção de hemoglobina em ratos Wistar. A farinha de soja com casca apresentou 37% a mais de fibra alimentar e maior teor de ferro (p 0,05). O Valor Relativo de Biodisponibilidade (VRB) da farinha de soja com casca e sem casca foram 68,5% e 67,1%, respectivamente, em relação ao sulfato ferroso (100%). A farinha de soja com casca submetida ao tratamento térmico (150ºC/30 minutos) apresentou maior teor de ferro e reduzido conteúdo de fitato, favorecendo a biodisponibilidade de ferro. Assim, a farinha de soja com casca apresentou melhor fonte de fibra alimentar e ferro do que a farinha de soja sem casca de comparável biodisponibilidade.

A STUDY OF THE RELATIVE BIOAVAILABILITY OF IRONFROM SOY FLOUR BY THE WAY OF HEMOGLOBINREGENERATION IN RATS SUFFERED FROMIRON DEFICIENCY ANEMIA / 营养学报

In order to clarify the disputing view-points in some publications, that the soy products are whether unfavourable or not to the bioavailability of diet iron, we estimated the relative bioavailability of the iron from soy flour by hemoglobin regeneration method in rats suffered from iron deficiency anemia. In this experiment the ferrous sulfate was used as a standard, wheat flour as a vehicle, and the pig blood powder as a reference substance. The iron content in the regeneration diet fed to rats of each group was 32 ppm in total, and among it 24ppm was originated from (1) soy flour, (2) soy flour plus wheat flour (half and half), (3) pig blood powder, (4) pig blood powder plus wheat flour (half and half), and (5) ferrous sulfate respectively.The experimental results showed that during the 5-week regeneration period the regenerated hemoglobin level of the rats of corresponding groups were (1) 6.6?1.6→9.4?1.7, (2) 7.0?0.9→10.4 ?1.5, (3) 6.4?1.6→ 11.4?1.4, (4) 6.1?0.6-11.1?1.9, and (5) 5.3?1.2-12.8 1.0, thereby the percentage of iron relative bioavailability of five groups were (1)45.4, (2)65.0, (3)74.0, (4)72.0, (5)100.0 respectively. The iron from soy flour showed a lowest bioavailability aalong the different diet sources in our exper-iment, and therefore the iron from soy products was unfavourable to prevent and treat the iron deficiency anemia. We also made some discussions and suggestions in this paper.