Within the scope of the master thesis we determined the content of biogenic amines (BA) and gamma-aminobutanoic acid (GABA) in buckwheat flours of different producers during spontaneous fermentation and after the addition of commercially available starter culture. The content of BA putrescine (PUT), cadaverine (CAD), tyramine (TYR), histamine (HIS), tryptamine (TRP), phenethylamine (PEA), spermidine (SPD) and spermine (SPM) and GABA in sourdoughs was determined after 24- and 48-hour fermentation. We found that spontaneous fermentation took place differently in each of the flours analyzed. High TYR contents (up to 65 mg/100 g), (up to CAD 73 mg/100 g) and (PUT up to 62 mg/100 g) were determined in the individual sourdoughs. The increased content of nutritionally problematic HIS was determined in only one fermentation (24 mg/100 g). The addition of starter culture led to lower CAD and TYR content and higher PUT content, with more than 100 mg/100 g being determined in one of the flours after 48 hours of fermentation. The contents of GABA and BA were higher after 48 hours of fermentation. The addition of starter culture did not uniformly influence the formation BA and pH of the sourdoughs of different flours, which indicates a great influence of the autochthonous microflora. The antioxidant content in sourdoughs was higher than in flours, but the influence of fermentation time and addition starter culture was small. Lactic acid bacteria of the autochthonous microflora were isolated from spontaneously fermented sourdoughs. Fermentation with an isolated sourdough culture from chickpeas sourdough led to a lower formation of nutritionally undesirable BAs compared to spontaneou fermentation. The content of BAs and GABA was lower in bread than in dough. The decrease was more pronounced in the crust than in the core of the bread.