Comparison of lactic acid contents between dried and frozen tarhana

Abstract

The lactic acid content of tarhana produced with different dough treatments was determined. Trials were performed to see the effects of different parameters on organic acid produced during fermentation. In these trials, fermentation time, yogurt content and preservation method parameters were varied. Increasing fermentation time had a significant effect on lactic acid formation as well as total organic acid content of tarhana (p < 0.01). In the samples of tarhana with 50% yogurt, total acidity increased 29.9% in the first 48 h of fermentation. During the subsequent 48 h the increase was only 3.6%. Lactic acid increased 17.7% during the first 48 h followed by an increase of 3.1% during the next 48 h of fermentation in these same samples. On the other hand, when yogurt content was increased from 50% to 75%, total acidity in the first 48 h was 17.0% greater than the samples with 50% yogurt. There was also a 20.2% increase in lactic acid as well.

The highest acidity and lactic acid levels were determined in the samples using 75% yogurt. Yogurt level had a significant effect on all the analytic parameters (p < 0.01). However, it is possible that increasing the amount of yogurt to this level would cause technological problems because of the increase in water and fat contents.

Of the two preservative methods utilized in this study, sun drying produced higher organic acid (1.97 g/100 g) and lactic acid (1.29 g/100 g) levels than samples that were frozen (1.64 g/100 g; 1.06 g/100 g, respectively). Preservative methods had a significant effect on moisture, total acidity, lactic acid (p < 0.01) and oil (p < 0.05) content of tarhana.