Biodisponibilidade de ferro e qualidade proteica do cultivar de soja UFVTN 105AP com elevado teor proteico

• Autor(a) principal: Carvalho, Ariela Werneck de
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2718
• topic: Farinha de soja; Biodisponibilidade de soja; Qualidade protéica; Iron bioavailability; Protein quality; Soy flour; CNPQ::CIENCIAS DA SAUDE::NUTRICAO

The soybean (Glycine max (L.) Merrill) is an important legume to human nutrition due to its nutritional and functional properties. It is important to establish and research a new cultivar of soybean to improve taste and chemical composition and decrease anti-nutritional factors. Therefore, the aim of this study was to evaluate the centesimal composition, mineral concentration, phytic acid, urease activity, tripsin inhibitor, nutritional categorization by serving size, amino acid profile, protein solubility, iron bioavailability and protein quality of a hull and hulless soybean flour from the UFVTN 105AP cultivar, heat-treated at 150o C for 30 minutes. Iron bioavailability was evaluated by the hemoglobin iron-depletion-repletion method in male Wistar rats. The animals were feed a depletion diet for 21 days and a repletion diet for 14 days. In the repletion phase, the control diet (ferrous sulphate) and the two test diets (hulled and hulless soy flour) were tested with 6, 12 and 24 ppm of iron. The protein quality was evaluated in male Wistar rats randomly to 4 groups (n= 6/group), for 14 days. Two groups (test) received their hulled and hulless soybean flour test meals, one group received a diet without protein and another received a casein diet. Weight gain (WG), feed intake (FI), food efficiency ratio (FER), protein efficiency ratio (PER), net protein ratio (NPR), true digestibility (TD) and protein digestibility&#8211;corrected amino acid score (PDCAAS) were determined. The hulled soy flour showed higher total alimentary fiber, calcium, iron, lower protein and phytic acid than the hulless soybean flour. The phytic acid:iron molar ration was two times lower that the hulless soy flour and the phytic acid: zinc molar ration was also lower. The serving size (50 g) of the flours was classified as an excellent source of protein, Cu, Mg, Zn and Mn, a good source of lipids, dietary fiber, and K and a source of Ca. For iron, the hulled soy flour was classified as an excellent source and the hulless soy flour as a good source. The heat-treatment decreased urease activity inhibited the tripsin inhibitor and increased protein solubility in both flours. The amino acid profile of hulled and hulless soy flour had been similar between themselves, being limiting only to valin by FAO/WHO nutritional requirements. A similarity of the hemoglobin serum gain between the control (ferrous sulphate) and test groups (hulled and hulless soybean flour) was observed. However, the group treated with hulless soy flour contained iron at a 24 ppm level showing inferior values compared to the control (p< 0.05). The relative iron bioavailability of the hulled soybean flour and hulless soybean flour was 68.5% and 67.1%, respectively, in relation to ferrous sulphate. In the protein quality assay, the PER and NPR did not differ (p> 0.05) among experimental groups. The PER of the hulless soy flour appeared similar to casein (p> 0.05). Although the PER of the hulled soy flour was inferior (p<0.05) to casein, it did not differ (p>0.05) from the hulless soy flour. The TD of hulled and hulless soy flour did not differed between themselves (p> 0.05), but were inferior to casein (p<0.05). The PDCCAS was lower than the TD, probably by limiting amino acids. The protein quality from PER and NPR indicated that the flours promoted adequate growth and development of the animals. True digestibility was high, but was inferior to casein. The genetic improvement provided an adequate balance of essential amino acids, qualitatively and quantitatively, with the exception of valin. The hulled flour can represent a valuable strategy to increase the dietary fiber intake, and to supply 35% more iron than the hulless soybean flour. A new cultivar can be used to assist iron requirements of individuals with low iron intake in conventional and non conventional diets. Moreover, the soybean processing improved the proteins quality, indicating the use of the hulled soybean flour.