Biochemistry & Analytical Biochemistry

Abstract

Effect of Gamma-Irradiation or/and Extrusion on the Nutritional Value of Soy Flour

Refaat G. Hamza, Safaa Afifi, Abdel-Rahman B. Abdel-Ghaffar and Ibrahim H. Borai

Although soybean is rich with high amount of protein, phenolic compounds and other bioactive nutrients, their bioavailability and utilization by either humans or animals are relatively low due to the presence of high proportions of various antinutrients. Therefore, this study was assessed to use gamma irradiation or/and extrusion for inactivation or removal of certain antinutritional factors as well as study the effect of these processing method on the nutritional value of soy flour (the simplest form of soy protein). Analyses included proximate composition, the level of total phenols and levels of antinutrients (phytic acid, tannins and trypsin inhibitors) of raw and processed soy flour. In addition, amino acid contents were analyzed by using high performance amino acid analyzer-Biochrom 20, gas chromatography was used for analysis of fatty acids as well as phenolic compounds were determined by high performance liquid chromatography. The results showed that moisture, crude protein, crude fat, crude fiber, and ash were unchanged by the irradiation (5 and 10 KGy) or/and extrusion except the moisture content was decreased by extrusion. γ-irradiation or/and extrusion processing significantly reduced the levels of phytic acid, tannins, and trypsin inhibitor while the total phenols was increased relative to unprocessed control samples. All essential amino acids, fatty acids and phenolic compound were changed by different values. From these results, it could be possible to demonstrate the benefits of γ-irradiation or and extrusion processing on the nutritional properties of soy flour by reducing its antinutritional contents and improving some of functional nutrients.