Enhancement of traditional tarhana with different parts of oleaster (Elaeagnus angustifolia L.): physicochemical, functional, nutritional and sensory properties

Abstract

The aim of this study was to evaluate the influence of incorporating 15% and 30% of oleaster layers (exocarp, mesocarp, endocarp) on the physical, functional, chemical, textural, and sensory properties of traditional tarhana. The addition of exocarp and mesocarp flour improved the functional properties of the tarhana samples compared to the control tarhana (p<0.05). In contrast, the addition of endocarp flour had a limited effect. The incorporation of oleaster components into tarhana resulted in a significant increase in protein, fat, ash, total phenolic content, antioxidant capacity, SDF, IDF, and TDF levels compared to control tarhana (p<0.05). In addition, there was a significant reduction in rapidly available glucose (RAG) and starch hydrolysis index (SHI), along with an increase in slowly digestible starch (SDS) with the incorporation of higher levels of exocarp, mesocarp, and endocarp flour. Except for the mesocarp and endocarp layers, the use of the exocarp layer in tarhana samples improved the soup's texture, characterized by increased firmness, cohesiveness, work of cohesion, and consistency. Tarhana samples containing 15% exocarp and 30% mesocarp flour were the most preferred by the panelists. This study provides valuable insights into the influence of different oleaster flour types on tarhana properties.