Avaliação da qualidade proteica de diferentes cultivares de soja e farinha mista de soja e milho e análise proteômica da soja
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2011-11-29
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Universidade Federal de Viçosa
Resumo
A soja (Glycine max (L.) Merrill) é uma leguminosa com participação importante na alimentação humana. O melhoramento genético tem desenvolvido novos cultivares com modificações nas frações protéica e lipídica do grão, gerando a necessidade de estudos para avaliar a concentração de nutrientes e valor biológico desses cultivares. Neste estudo avaliaram-se a composição centesimal, valor biológico, o perfil aminoacídico, e a qualidade nutricional de cinco cultivares de soja isolados e em associação ao milho (farinha mista). Foi realizada também a análise da expressão diferencial de proteínas por eletroforese bidimensional dos cinco cultivares de soja utilizados (CD 201, CD 2013 PTA, Monarca, CS 3033PTA e UFVTN105AP) além do cultivar BARC-8. A qualidade protéica foi avaliada em ratos machos Wistar, distribuídos ao acaso em 11 grupos (n=6), durante 14 dias. Os dois grupos testes receberam dietas à base de farinhas de soja misturadas ou não com farinha de milho tratadas a 150o C por 30 minutos. Um grupo controle recebeu dieta livre de nitrogênio e outro grupo de referência, recebeu dieta à base de caseína. Avaliaram-se: ganho de peso (GP), consumo alimentar (CA), coeficiente de eficiência alimentar (CEA), razão da eficiência protéica (PER), razão protéica líquida (NPR), digestibilidade verdadeira (DV) e escore químico corrigido pela digestibilidade (PDCAAS). O perfil aminoacídico das farinhas de soja integral apresentou-se limitante para cistina e metionina, apenas no cultivar Monarca pelo padrão da FAO/WHO de recomendação nutricional. Não houve diferença entre o consumo alimentar dos animais, no entanto, os valores CEA, PER, NPR, DV e o PDCAAS tanto dos animais alimentados com soja quando da mistura soja e milho foi menor que o padrão caseína (p>0,05), indicando que as farinhas não foram adequadas para promover o crescimento e o desenvolvimento dos animais mesmo quando o escore calculado foi adequado. Apesar do melhoramento genético ter proporcionado um aumento dos teores de proteína não se pode afirmar que proporcionou um equilíbrio qualitativo dos aminoácidos essenciais. Outros fatores como a digestibilidade e a biodisponibilidade das proteínas podem ter interferido na avaliação da qualidade protéica. A análise diferencial das proteínas presentes nos grãos de soja por eletroforese bidimensional revelou entre 650 e 1900 spots sendo que destes em média 18 apresentaram diferenças em sua expressão. A análise dos perfis eletroforéticos indica que o ganho de proteínas modificou principalmente a expressão das proteínas de reservas, e que a fração protéica em uma soja de alto teor não é igual a outra de teor normal.
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.
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.
Descrição
Palavras-chave
Glycine max, Avaliaçãoo biológica, Eletroforese Bidimensional, Glycine max, Biological evaluation, Dimensional electrophoresis
Citação
NUNES, Renato Moreira. Evaluation of protein quality of different cultivars of soybean and soybean meal and corn mixed and proteomic analysis of soybean. 2011. 65 f. Tese (Doutorado em Análises quantitativas e moleculares do Genoma; Biologia das células e dos tecidos) - Universidade Federal de Viçosa, Viçosa, 2011.