EFFECT OF SUBSTITUTION OF WHEAT FLOUR WITH OAT AND BARLEY MEAL ON THE FUNCTIONAL, RHEOLOGICAL AND SENSORY PROPERTIES OF TARHANA

Addition of whole cereal grains’ meal as a source of dietary fibers for the development of tarhana as a value-added functional food was the aim of this study. The effect of substituting wheat flour 72% (WF) with different ratios of whole wheat meal (WWM), oat flakes meal (OFM), whole barley meal (WBM) and mixed-cereal meal (OFM& WBM) on functional, rheological, color and sensorial properties of tarhana samples was determined. Whole cereal grains’ meal showed higher contents of protein, lipids, ash, crude fibers and total phenolic compounds in comparison to wheat flour (72%). pH values of tarhana samples were reduced from 5.22-5.89 to 4.81-5.09 after 72 h. of fermentation. The flow behavior index of tarhana soup samples ranged between 0.11-0.19, indicating the pseudoplasticity of tarhana samples. The higher value of consistency coefficient was recorded for OFM 50% sample followed by WWM 100% sample. Fermentation loss values of tarhana samples ranged between 7.12% for OFM 25% sample and 12.61% for mixed-cereal 50% sample. Substitution of WF in tarhana formulations with whole cereal grains’ meal reduced the yellowness of tarhana samples. Addition of different whole cereal grains’ meal significantly (p<0.05) improved water and oil absorption capacity of tarhana samples. Also, partial substitution of WF with OFM and mixed-cereal meal at ratio of 50% in tarhana recipe has significantly (p<0.05) increased foaming capacity and stability of the final product. The highest values of sensory parameters were observed in Tarhana soups prepared with OFM at ratios of 25& 50%, mixed-cereal meal at 50% and  the control sample. According to the results of this study, it is possible to partially substitute wheat flour with whole cereal grains’ meal in tarhana production in attempt to have a product combining the nutritional value of whole cereal grains and the health benefits of lactic acid bacteria.