Evaluating the effect of barley sourdough containing Pediococcus stilesii starter on phytate content of Barbari bread

In this study, the effect of barley sourdough containing Pediococcus stilesii starter with different dough yield (160, 270 and 450) on phytate content of produced dough and Barbari bread was investigated. For this purpose, after applying 28, 32, 36°C fermentation temperatures and 16, 24, 32 h fermentation times, the amount of phytate was evaluated using a spectrophotometric assay based on the measurement of iron absorption. The results of statistical analysis showed that the pH and phytic acid content of produced dough and Barbari bread were significantly (P ≤ 0.05) decreased with increasing fermentation time and temperature, while titratable acidity was significantly increased (P ≤ 0.05). Furthermore, increasing yield dough from 160 to 450 resulted in significant increase (P ≤ 0.05) in titratable acidity and significant decreases (P ≤ 0.05) in pH and phytic acid content of produced dough and Barbari bread. Regression equation between sourdough titratable acidity and phytic acid content of produced dough and Barbari bread had respectively correlation coefficients equal to 0.947 (linear model) and 0.842 (logistic power model), and by increasing of sourdough titratable acidity, the contents of phytic acid were also decreased. Based on obtained results, controlled fermentation of sourdough can effectively reduce the amount of phytic acid of Barbari bread in comparison to control sample.