The effect of fermentation on viscosity and protein solubility of Boza, a traditional cereal-based fermented Turkish beverage

Boza was prepared with corn, rice and wheat flour. Alterations in pH, water-soluble protein content and viscosity were observed during a 30 h fermentation period. Fermentation caused a reduction in pH, whereas the water-soluble protein content of boza significantly increased (P<0.05). The power law model described the pseudoplastic behaviour of boza. The consistency (k) and flow behaviour index (n) values indicated that the viscosity of boza decreases as the temperature increases. The k values of fermented and unfermented boza samples were significantly (P<0.05) different from each other at 10, 20 and 30 °C. The n values of unfermented boza did not vary significantly with temperature whereas n values of fermented boza changed significantly.