Changes in some physical and nutritional properties of tarhana, a Turkish fermented cereal food, added various phytase sources

The effects of three different levels of baker's yeast, barley malt flour and a microbial phytase supplement have on fermentation loss, colour, pH, total and HCl-extractable ash (HEA) and HCl-extractable phosphorus (HEP) ratio of Turkish tarhana were investigated. Fermentation loss, expressed as dry matter loss, was used for estimation of tarhana processing yield, including the fermentation, drying and grinding processes, and found on average to be 12.96%. Fermentation loss provided a proportional increase in the total ash and phosphorus content of the samples and pH decreased by adding microbial phytase. HEA and HEP content as a measurement for mineral bioavailability increased from 68.32% (dough) to 82.07% (tarhana), and from 60.45% to 83.63%, respectively, during the production process. Additions of yeast, barley malt and phytase significantly raised the HEA and HEP content (P < 0.01). Among the phytase sources, yeast was the most effective additive on the ash and phosphorus extractability. The combination of 2.5% yeast and 4% malt was the optimum treatment to obtain a low fermentation loss and high HEA and HER Increasing HEA and HEP values could mean higher bioavailability of minerals bound by phytic acid.