Avaliação da qualidade proteica de diferentes cultivares de soja e farinha mista de soja e milho e análise proteômica da soja

• Autor(a) principal: Nunes, Renato Moreira
• Data de Publicação: 2011
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/257
• topic: Glycine max; Avaliaçãoo biológica; Eletroforese Bidimensional; Glycine max; Biological evaluation; Dimensional electrophoresis; CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL

Soybean (Glycine max (L.) Merrill) is a legume with an important role in human nutrition. Genetic improvement has developed new cultivars with changes in protein and lipid fractions of the grain, leading to the need of studies to evaluate the concentration of nutrients and biological value of these cultivars. This study assessed the centesimal composition, biological value, amino acid profile, and the nutritional quality of five cultivars of soybean alone and in combination with the corn (mixing flour). It was also performed the analysis of differential expression of proteins twodimensional electrophoresis of the five cultivars of soybean used (CD 201, CD 2013 PTA, Monarca, CS 3033PTA e UFVTN105AP), apart from the cultivar BARC-8. The protein quality was evaluated in male Wistar rats, randomly distributed in 11 groups (n=6) during 14 days. The two tested groups received soybean-based diet whether or not mixed with corn flour treated at 150°C for 30 minutes. A controlled group received a nitrogen-free diet and other reference group received a casein-based diet. The weight gain (WG), feed intake (FI), the food efficiency ratio (FER), the protein efficiency ratio (PER), net protein ratio (NPR), true digestibility (TD) and protein digestibility corrected amino acid score (PDCAAS) were assessed. The amino acid profile of soybean whole flour presented limiting for cystine and methionine only in the cultivar Monarca by the standard of FAO/WHO of nutritional recommendations. There wasn t difference between the animals food consumption, however, the values of the FER, PER, NPR, TD and the PDCAAS both animals fed with soybeans and mixture of soybean and corn was lower than the standard casein (p>0,05), indicating that the flours were not adequate to promote growth and the development of animals even when the score was properly calculated. Despite the genetic improvement has provided an increasing of the protein content, we cannot affirm that it provided a qualitative balance of the essential amino acids. Other factors such as the digestibility and bioavailability of the proteins may have interfered in the evaluation of protein quality. The differential analysis of the proteins in the soybeans by two-dimensional electrophoresis showed between 650 and 1900 spots of which about 18 presented differences in their expression. The analysis of electrophoretic profiles showed that the gain of proteins changed mainly the expression of storage proteins and that the protein fraction in a high content soybean is not like in another of a normal content.