Functional Enrichment of Tarhana: Effects of Plantain (Plantago lanceolata) Addition on Physicochemical Properties, Antioxidant Capacity, and Sensory Characteristics

In this study, the effects of adding ribwort plantain (Plantago lanceolata) at different levels (0-20%) on the physicochemical, color, antioxidant, microbiological, and sensory properties of tarhana were investigated. According to the results, while ash content and titratable acidity showed significant differences among the samples (p<0.05), no significant differences were observed in moisture content, pH, water activity, and viscosity (p>0.05).  The ash content increased from 5.90±0.36% in the control sample to 6.88±0.21% with the addition of 10% Plantago lanceolata, while titratable acidity increased from 20.16±0.177% in the control sample to 24.66 ± 0.81% with the addition of 20% Plantago lanceolata (p<0.05). In the color analyses, as the proportion of Plantago lanceolata increased, the L* value decreased from 65.66±0.97 to 60.28±0.44, while the b* value decreased from 14.23±0.12 to 12.51±0.73 (p<0.05). In terms of antioxidant properties, the total phenolic content increased from 0.1809±0.0118 µg GAE µL^-1 in the control sample to 0.2995±0.0136 µg GAE µL^-1 with the addition of 20% Plantago lanceolata. Similarly, iron-chelating capacity increased from 0.0092±0.0005 µg EE µL^-1 to 0.02088±0.00054 µg EE µL^-1, while the FRAP value increased from 0.09430±0.0067 µg TE µL^-1 to 0.17974±0.0238 µg TE µL^-1 (p<0.05). No yeast and mold growth was detected in any of the samples during microbiological analyses. In the sensory evaluation, the color and consistency scores decreased to 2.55±1.44 and 2.95±1.21, respectively, with the addition of 20% Plantago lanceolata (p<0.05). However, overall acceptability scores ranged from 3.27±1.12 to 3.91±1.08, with no statistically significant differences among the groups (p>0.05). Overall, 5–10% P. lanceolata addition was considered appropriate in terms of the quality characteristics and sensory acceptability of tarhana.