gamma radiation

Cellulases and xylanases are hydrolytic enzymes that randomly cleave the β-1, 4 backbones of the cellulose and arabinoxylans of wheat flour and are widely used in the bakery industry as a dough texture improver in the formulations of flour products. Creating novel sources of a microbial strain using induced gamma irradiation can increase enzyme production for bakery industrial usage. According to this, Co60 gamma irradiation has been used to develop a mutant strain of Trichoderma afroharzianum. Trichoderma mutants were isolated, and the qualitative and quantitative screening were used to evaluate the extracellular enzyme production with the wheat bran waste as a substrate. The best Trichoderma mutant isolate was identified using the DNA barcoding method. The highest xylanase activities were observed in the superior mutant isolate of Trichoderma afroharzianum NAS107-M82, which is approximately 3.3 times higher than its parent strain. The electrophoretic pattern of proteins showed that the exo-glucanase I, endo-glucanase III, and the xylanase I enzymes hydrolyzed the wheat bran, synergistically. Overall, gamma irradiation-induced mutation could be an expedient technique to access such superior mutants for the bioconversion of wheat bran wastes to xylanase enzyme.

Aspergillus flavus is one of the important species of molds that can produce toxins during improper storage of wheat grains. In this study, different amounts of calcium oxide (0, 0.5, and 1%) were mixed with wheat samples containing mold spores. After 20 days, the samples were exposed to gamma radiation (0, 5, 10, 15, and 20 KGy). The presence of A. flavus, Aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), and aflatoxin G2 (AFG2) was assessed in samples. The results indicated that the effects of calcium oxide, gamma irradiation, and their interactions were significant on A. flavus, AFB1, and AFB2 contamination. Furthermore, other toxins like AFG1 and AFG2 were not found in the samples. An additional reduction in AFB1 and AFB2 was observed when irradiation was accompanied by Cao, and the maximum inhibition of aflatoxin production was achieved at 0.5% CaO. Consequently, based on the standard maximum limit of 10 KGy for cereals, the findings of this research suggest that 0.5% of calcium oxide and 10 KGy of irradiation could be applied in the storage of wheat grains to mitigate A. flavus, AFB1, and AFB2.

The combined effect of gamma radiation and Carum copticum C. B. Clarke essential oil were determined for the management of Tribolium confusum Du Val larvae and adults. Experiments were carried out at 27 ± 1 ºC and 65 ± 5% R. H. under dark condition and three steps were designed: (A) Application of gamma radiation and essential oil at the same time. (B) Irradiation followed by essential oil. (C) Essential oil followed by irradiation. Radiation doses of 100 to 500 Gy were applied in combination with 5.97, 7.52 and 10.47 μl/l air of essential oil for the adults and 1.91, 4.08 and 12.02 μl/l for the larvae. The result showed that the combination of gamma radiation with C. copticum oil increased larval and adult mortality compared with the control, so that, the interaction of 500 Gy with 10.47 μl/l air for adults and 12.02 μl/l air for larvae caused 100% mortality in 13 and 8 days, respectively; although 100% of the larvae and adults mortality at 500 Gy alone caused within 22 days. It was revealed that the combination of irradiation and essential oils could be used as an effective control method and a good alternative to fumigants.