Quinoa dough fermentation by <i>Saccharomyces cerevisiae</i> and lactic acid bacteria: Changes in saponin, phytic acid content, and antioxidant capacity

Abstract

The effects of two fermentation processes (common fermentation with <i>Saccharomyces cerevisiae</i> and fermentation by <i>Lacticaseibacillus casei</i> subsp. <i>casei</i> PTCC 1608 and <i>Lactiplantibacillus plantarum</i> subsp. <i>plantarum</i> PTCC 1745) on pH, titratable acidity, total phenolic and flavonoid contents, antioxidant capacity, saponin content, as well as phytic acid content of quinoa dough were investigated during the 24-h fermentation (4-h interval). According to the results, the highest titratable acidity was observed in the samples fermented by <i>L. casei</i> subsp. <i>casei</i>. Moreover, the highest antioxidant capacity was observed after 12 h of fermentation by <i>L. plantarum</i> subsp. <i>plantarum</i> (31.22% for DPPH, 104.67% for FRAP) due to a higher concentration of phenolic compounds produced (170.5% for total phenolic content). Also, all samples have been able to reduce saponin by 67% on average. Furthermore, the samples fermented by <i>L. plantarum</i> subsp. <i>plantarum</i> showed the most significant decrease in phytic acid content (64.64%) during 24-h fermentation. By considering the reduction of the antinutritional compounds and improvement in the antioxidant properties of quinoa flour, the <i>Lactiplantibacillus plantarum</i> strain was recommended.