Gamma irradiation is one of the alternative methods for food preservation to prevent food spoilage, insect infestation and extending the shelf life by reducing the microbial load. Therefore, this investigation was carried out to determine the influence of gamma radiation on rheological properties of wheat flour and its baked breads. Commercial wheat (Triticum sativum) flour was irradiated with 2.5, 5.0 and 7.5 kGy using cobalt-60 gamma chamber (1.32816 kGy/h). Slight radiation effects on the farinograph properties included water absorption (%) and degree of softening (B.U.) which increased by irradiation. While values of arrival time (min.), dough development (min.) dough stability (min.), as extensograph properties (elasticity (B.U), extensibility (mm), P.N and energy (cm2) decreased by different gamma irradiation doses. Total bacteria, molds and yeasts counts were reduced and inactivated by the irradiation process. On the other hand, chemical composition of wheat flour did not a significant affected by gamma irradiation, and did not caused any significant changes in there analysis of variance for sensory evaluation score (Appearance, taste, texture, color and odor) of white baked breads from non-irradiated and irradiated white flours. In conclusion, the overall dose of 2.5, 5.0 and 7.5 kGy are very effective for microbial decontamination of wheat flour, and does not adversely affect on their quality.
Keywords: Gamma rays, wheat flour, rheological characteristics and microbial decontamination.