The effect of CO60 on the physical and physicochemical properties of rice

Owing to its chemical composition and production chain, rice is susceptible to contamination by fungi. Among other techniques, the application of gamma radiation has been suggested as a method to ensure food safety. However, such radiation can alter the chemical composition of the food. Thus, the objective of the present work is to evaluate the centesimal composition, caloric value, pH, total titratable acidity, and coloration of polished white rice subjected to different doses of Co60 gamma radiation (0 kGy, 6.5 kGy, and 7.5 kGy). The results demonstrated that while gamma radiation did not cause significant alterations in the centesimal composition, caloric value, and titratable acidity of the rice, increasing doses substantially decreased the pH and intensified the coloration. Under controlled radiation conditions, a 6.5-kGy dose can render rice safe for consumption without significantly compromising its physical and physicochemical properties.

Development of rice seedlings grown from pre-hydrated seeds and irradiated with gamma rays

Techniques used to induce mutations, such as ionizing radiation, are an effective tool in increasing genetic variability in breeding programs of species of economic interest. This study aimed to evaluate the effect of different doses of Co60 gamma radiation on previously soaked seeds on the emergence and early growth of seedlings of two rice cultivars. To do this, seeds (25% moisture) of BRS Querência and BRS Fronteira were irradiated with zero (control), 50, 100, 150 and 200 Gy, and then sown in trays containing soil and kept in a greenhouse. The results showed that gamma radiation affected seedling development, where the highest dose tested (200 Gy) significantly reduced the emergence and the index of emergence speed. Growth parameters were reduced greater reduction in cv. BRS Querência. For antioxidant enzymes, superoxide dismutase expressed little variation for the periods evaluated. Already ascorbate peroxidase and catalase showed a significant increase in horsepower cv. BRS Fronteira at 14 DAS, followed by an increase in both cultivars ascorbate peroxidase activity at 28 DAS. The highest antioxidant capacity observed in cv. BRS Fronteira conferred greater tolerance to stress caused by gamma radiation.