| Abstract [eng] |
This study is dedicated to evaluate the influence of biological treatment of cereals using lactic acid fermentation on Fusarium spp. changes in the concentrations of mycotoxin deoxynivalenol (DON) and DON conjugates such as DON-3-𝛽-D-glucoside (D3G), 3-acetyldeoxynivalenol (3-ADON) and 15-acetyldeoxynivalenol (15-ADON) in contaminated barley grains. Samples of barley grains of different contamination with DON concentrations of 223 µg/kg, 248 µg/kg, 460 µg/kg, 996 µg/kg and 6563 µg/kg were fermented for 48 hours with strains of lactic acid bacteria (LAB) (L. casei, L. plantarum, L. paracasei, L. uvarum and L. brevis) in MRS medium and evaluated DON and DON conjugate concentrations in barley grains before and after fermentation using UHPLC-OrbitrapHRMS equipment. Biological treatment of barley significantly reduced DON concentrations from an average 1698 µg/kg to 1180 µg/kg, D3G concentrations from 519,2 µg/kg to 113,96 µg/kg, 3-ADON from 82,4 µg/kg to 37,36 µg/kg and 15-ADON from 339,4 µg/kg to 185,2 µg/kg. This effect was influenced by the LAB strain used and the specificities of their reproduction and secreted metabolites in different medium of Fusarium spp. contamination. The highest decontamination effect of barley contaminated with DON mycotoxins was achieved using L. casei strain for fermentation, DON content in barley samples decreased, on average, by 47%, D3G – 82,4 %, 15-ADON – 46,1 %, and 3-ADON – 55 %. L. casei also reproduced well during fermentation with different contaminants in barley and produced organic acids. The relations between mycotoxin-contaminated barley grains (before fermentation) and enzyme profiles, indicates that Fusarium spp. microscopic fungi producing DON and the DON conjugates have a wide range of enzymatic activities. Decreases in amylase and xylanase activity were observed during LAB fermentation, whereas increases in protease activity were observed in both low-contamination barley and high-contamination barley samples. It can be assumed, that fungi with proteolytic activity in cereal raw material can be activated during fermentation and participate in the detoxification process in combination with LAB (L. casei) mycotoxins. One of the promising ways to control the microbiological contamination of grain raw materials was the extrusion of waste from the brewing industry – brewer’s spent grain in combination with LAB fermentation. Studies have shown that extrusion technology can increase the nutritional safety of brewer’s spent grain and be adapted for the production of LAB fermented products. The obtained results suggest that the reduction in contamination may be related not only to bacterial conjugation but also to the enzymatic degradation of mycotoxins during LAB fermentation. In conclusion of this study, the observed effect of fermentation on the reduction of DON and DON conjugates opens the prospects for the development of new biopesticides and opportunities to increase the sustainability of grain production. |
