| Abstract [eng] |
In this work, the stages of grain processing as preparation for milling and fractionation and secondary process (e.g. sourdough fermentation) been evaluated. One part of the research aimed at evaluating the external and internal (post-cleaning) contamination of wheat grain samples of different years by microscopic fungi and identification of these species. Special attention paid to the bread making and assessment of the influence of milling process and biotechnological factors (microbial fermentation) on DON and other mycotoxins in wheat products. Results of analysis of an external and internal infection of wheat grains by microscopic fungi showed that the main genus were Fusarium spp., Alternaria spp., Penicillium spp. and Verticillium spp., of which Fusarium spp. and Alternaria spp. were the main contaminants found also in the case of internal infection of the grains. Fractionation after grinding statistically significantly reduced (p < 0.05) the deoxynivalenol (DON) concentration in the model milling fractions (37.2 ‒ 64.1 %), as the lowest levels of DON transfer to the smallest fraction (<213 μm). However, the study showed that this is not sufficient to control the risk, as other mycotoxins are concentrated in smaller milling fractions, while DON remains predominantly in the largest particle fraction (> 500 μm). Fermentation with selected strains of lactic acid bacteria allowed complete elimination or effective reduction of DON levels compared to initial levels: after 48 h fermentation, DON levels decreased by 80.5 ‒ 95.2 % during fermentation of high contamination level milling fractions with L. plantarum LUHS135, and by 81.2 ‒ 94, 9 % during fermentation with P. acidilactici LUHS236. It was been founded that after fermentation of low contamination level samples with L. plantarum LUHS135 and P. acidilactici LUHS236, the contents of 15-AcDON, AOH, D3G and HT-2 toxin were detected below the detection limit (p < 0.05). Summarizing the results of the study, it can be stated that only by applying physical methods (cleaning, milling and fractionation) for grain treatment and biotechnological means (fermentation with selected lactic acid bacteria), it would be possible to significantly reduce or completely eliminate DON and other mycotoxins in wheat-based fermented products, thus increasing the safety of wheat bread. |
