Composição química e valor protéico do resíduo de soja em relação ao grão de soja

Abstract

CHEMICAL COMPOSITION AND PROTEIN VALUE OF THE SOYBEAN RESIDUE IN RELATION TO THE SOYBEAN GRAIN. The aim of this research is to evaluate the chemical composition and protein value of soybean residue, which is a sub product of soybean oil extraction. The centesimal composition, energy value and amino acid contents were determined from soybean residue and soybean grain. The protein value was estimated by means of biological indexes. Weaning male Wistar rats (n = 24) were divided into four groups that were fed for ten days with 10% protein diets (soybean residue, soybean grain, casein- control) or a non-protein diet. The soybean residue showed a greater content of protein (47%) and lower energetic value (334 kcal/100 g) than soybean grain (40% e 452 kcal/100 g, respectively) and it also showed an essential amino acid score of 101% compared to the reference pattern and protein digestibility of 88%. Protein quality of soybean residue is similar to the protein of soybean grain (protein values of 87% and 85%, respectively), according to RNPR (Relative Net Protein Ratio) and PDCAAS (Protein Digestibility-Corrected Amino Acid Score) indexes. The soybean residue is a source of carbohydrates, minerals, fibers and adequate protein in nutritional terms and it shows advantages in relation to soybean grain such as lower energetic value and greater protein content.