Resumo

Flaxseed is an oilseed, rich in proteins, lipids and dietary fiber. The golden and brown flaxseed is considered a functional food, and their grains are rich in dietary fiber, omega 3 and omega 6. The golden flaxseed is grown in cold climates and has milder flavor than the brown flaxseed. The irradiation of food is important for the preservation of various types of grains, preventing contamination by pathogenic and toxigenic microorganisms. The objectives were to assess the infection rate of aflatoxigenic Aspergillus in golden and brown flaxseed, evaluate the effectiveness of gamma radiation on the inhibition of these fungi and check the rate of seed germination. Brown flaxseed was obtained from CEASA-PE, and golden flaxseed was from public market of Vitoria de Santo Antão-PE. The grains were packaged and submitted to gamma irradiation process in the following doses: control (non-irradiated), 2.5, 5.0, 7.5, 12.5 and 10 kGy. After that, the beans were grown in culture medium AFPA(Aspergillus flavus and A. parasiticus agar) to search for contamination by aflatoxigenic fungi without previous treatment with NaClO. 50 grains were analyzed for each sample. The non-irradiated samples of brown flaxseed showed a 4% level of contamination by aflatoxigenic Aspergillus, while in golden flaxseed no presence of these fungi. Gamma radiation inhibits fungal contamination in all irradiated samples independent of dose. It was observed that the brown linseed germinated in the AFPA medium and the germination rate decreased with increasing radiation dose. In the case of brown flaxseed, germination rate was: 84% (2.5 kGy), 74% (5kGy), 50% (7.5 kGy), 36% (10kGy), 10% (12.5 kGy). The gold linseed, at doses of 2.5, 5, 7.5 and 10kGy was no change in the rate of germination by 27%, 33%, 23% and 3%, with no germination at the highest dose (12.5kGy). The control sample showed no aflatoxigenic Aspergillus in golden flaxseed, then there is no possibility of the presence of aflatoxins in grains analyzed from the public market. In brown flaxseed, despite the decrease of germination increased radiation, germination rates in such linseed were higher than the gold linseed, indicating a greater resistance to the radiation. Therefore, the gold linseed was more suitable for human consumption than the brown linseed with a view to the presence of toxigenic Aspergillus in this type of seed.