Effect of formulation on protein breakdown, in vitro digestibility, rheological properties and acceptability of tarhana, a traditional Turkish cereal food

Summary Three formulations of tarhana, a traditional Turkish fermented yogurt-wheat mixture used in soups, were prepared in the laboratory. The effects of white or wholemeal wheat flours and amount of yogurt on the protein breakdown, rheology and acceptability of the samples were measured and the samples were compared with single samples of homemade and commercial tarhana from Turkey. Replacement of white wheat flour with wholemeal flour and increasing the yogurt had little effect on protein breakdown, but the true- to crude-protein ratio fell slightly during fermentation. Tarhana soups behaved as pseudoplastics (n 0.8) closer to Newtonian flow (n= 1) were most liked in mouth feel; however high apparent viscosity and samples with less liked mouth feel were not less liked in overall acceptability than the commercial sample. In vitro digestibility of commercial tarhana was lower than the laboratory prepared tarhana.