The aim of the study was to determine the effect of fermentation on the phenolic compounds content, antioxidant potential, phytic acid content and dietary fibre content of three types of pseudocereals. Amaranth, quinoa and buckwheat seeds were homogenized and fermented spontaneously, with baker's yeast, with the addition of an inactive commercial sourdough and with a mixed starter culture LV1 under selected conditions (24 or 48 h at 20 °C and 30 °C, respectively). The fermented samples were lyophilized and methanolic extracts were prepared. Fermentation affected the change in all the parametres analysed. These varied depending on the type of pseudocereal, the method and the course of fermentation. The greatest contribution to the phenolic compound (PC) content and antioxidant potential (AOP) of amaranth and quinoa was obtained by fermentation at 30 °C for 48 h with the addition of an inactive commercial sourdough. Regardless of the fermentation method, a negative effect on PC and AOP was observed in buckwheat. Spontaneous fermentation for 48 h resulted in the most extensive degradation of phytic acid (PA) in all three pseudocereals (at least 80 %), while the use of sourdough at optimum conditions reduced the PA concentration by two thirds or more. The insoluble dietary fibre content generally increased in amaranth and quinoa during fermentation, but decreased in buckwheat. The soluble dietary fibre content of quinoa and buckwheat was successfully increased by the addition of sourdough alone, while a negative trend was observed in all cases with differently fermented amaranth. According to the parameters analysed, we would recommend the preparation of fermented (48 h, 30 °C) pseudocereals with the addition of an inactive sourdough.
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