Determination of some characteristic properties and antioxidant potential of tarhanas developed for vegan and celiac individuals

In this study, tarhana, one of the traditional fermented foods; Some characteristic features of the samples obtained by producing according to the diet of vegan individuals, celiac patients and both gluten-free and vegan individuals, and the antioxidant properties of the samples before and after in vitro digestion were determined. Fermented soy yogurt was produced using soy drink and chickpea, which is a plant-derived milk coagulator, for vegan and vegan-gluten-free tarhana samples before the production of tarhana. White wheat flour was used in the production of control and vegan tarhana, and gluten-free flour was used in the production of glutenfree and vegan-gluten-free tarhana. Cow's yogurt was used for control and gluten-free tarhana, while fermented soy yogurt made from soy drink was used for vegan and vegan-gluten-free tarhana. Tarhana samples were produced in home conditions and dried by sun drying method. Total phenolic matter and total antioxidant capacity analyzes were performed on tarhana samples by applying in vitro digestion with pH, acidity, moisture, ash, protein, total phenolic matter, total antioxidant capacity, color and sensory. The pH value of the tarhana samples is 5.10-5.87; acidity value 23.67-26.33%; moisture value 10.57-11.28%; ash values vary in the range of 1.95-2.25% in dry matter. The difference between the pH, acidity, moisture and ash values of the samples was found to be statistically insignificant (p>0.05). The protein content of the tarhana samples was between 4.77-12.24% in dry matter, and the difference between samples was found to be statistically significant (p<0.05). The total amount of phenolic substance 93.75-112.88 mg GAE/100 g; total antioxidant capacity is between 14.06- 20.29 µM TEAC/g. The difference between the total phenolic substance and antioxidant capacity of the samples is statistically significant (p<0.05). When the color values of tarhana samples were examined, it was concluded that the difference between the L* and a* values was statistically significant (p<0.05), the b* value was statistically insignificant (p>0.05), and the use of different flour was effective on the samples. Pre-digestion total phenolic content determination results applied to tarhana soups were 13.24 and 32.60 mg GAE/100 g; total phenolic substance determination results after in vitro digestion ranged from 19.94 to 24.43 mg GAE/100 g. The difference between the total phenolic content of the samples before and after digestion was found to be statistically significant (p<0.05). The total antioxidant capacity of tarhana soups was determined as 3.66 and 7.50 µM TEAC/g in pre-digestive samples; It is between 5.70 and 9.03 µM TEAC/g in samples after in vitro digestion. The difference between the total antioxidant capacity values of the samples was found to be statistically significant for pre-digestion (p<0.05), but not significant for postdigestion (p>0.05). The bioavailability of the total phenolic content of the soups was between 65.40% and 182.42%; The % change values of the total antioxidant capacity are between 6.42 and 132.43 as an increase and decrease. The difference between the samples for the % bioavailability and % change values was found to be statistically significant (p<0.05). As a result of the sensory analysis, of general acceptability, gluten-free tarhana was preferred mostly and the control group tarhana was at lowest preferred in terms. Keywords: antioxidant capacity, bioavailability, celiac disease, gluten-free, in vitro digestion, phenolic substance, tarhana, vegan nutrition