Nutritional, chemical and microbiological changes during fermentation of tarhana formulated with different flours

Abstract

Background: Tarhana is a fermented cereal product that is used for the preparation of one of the favourite soups in Turkish cuisine. Tarhana is a mixture of wheat flour, yoghurt, baker's yeast, salt, and various vegetables, spices and seasonings. It is obtained by mixing all ingredients in the recipe and afterwards the mixture is let to ferment at room temperature. Following fermentation tarhana is dried or frozen for long term storage. In this study, to improve the nutritional benefits of tarhana, whole wheat and chickpea flours were used as the sole source of flour. The changes in the phytic acid content, proteins and fermentation products were investigated in addition to some microbiological and chemical characteristics. Results: The effect of flour type on the phytic acid content was significant. No differences were observed in the glutenin band patterns of the wheat and whole wheat flours and their tarhana samples. Conversely, for the gliadin fractions, the bands of the wheat and whole wheat flours were more intense than their tarhana samples. The changes in the glutelin and prolamin fractions of the chickpea flour and the resultant tarhana dough were similar to the glutenin and gliadin fractions of wheat and whole wheat flours and their tarhana samples. In all samples, the yeasts displayed an undulant growth pattern and the effect of flour type and fermentation time on yeast growth was significant (P < 0.01). The effect of flour type (P < 0.01) and fermentation time (P < 0.05) on mesophilic LAB was significant. Similar behaviours were observed with the mesophilic LAB in all samples and their numbers remained closed to their initial numbers. The growth of thermophilic LAB was not influenced by the flour type, but the effect of fermentation time was significant (P < 0.01). Conclusions: The whole wheat and chickpea tarhana are found to be good alternatives to classical tarhana with their higher nutritional benefits but further investigations are needed for the assessment of their sensory properties.