Steady, dynamic and structural deformation (three interval thixotropy test) characteristics of gluten-free Tarhana soup prepared with different concentrations of quinoa flour.

Celiac disease is among the most important health problems and the most important feature of this disease is its being the only lifelong food allergy. To overcome this problem, some gluten-free and starch based food products have been generally introduced to the market; however, these products are starch based with low nutritive value. Therefore, it is important to enrich such products for individuals who are obliged to be nourished by gluten-free diet. In this study, wheat flour was replaced with quinoa flour (QF) in the production of tarhana. The objective of this work was to investigate the steady shear, viscoelastic and deformation and recovery properties (applying three interval thixotropy test (3ITT)) of gluten-free tarhana soups prepared with different concentrations of QF (40%, 50%, and 60%). It was found that the soups fitted well (R(2)  > 0.99) Ostwald de Waele model and exhibited shear thinning behavior. Besides, elastic properties dominated the viscous properties. Although the maximum deformation and recovery were determined at 40% concentration level, minimum deformation and recovery properties were specified at 60% concentration level. The results suggest that QF can be used in gluten-free tarhana formulations to enhance rheological properties.

PRACTICAL APPLICATIONS: Malnutrition is currently widespread in many areas of the world. Therefore, it must be focused on the cheap, but nutritious plant protein and mineral sources, such as legume and cereals. Several recent studies have showed the successful formulation of pseudocereal containing cereal based products. Tarhana is a traditional fermented food made of mainly a mixture cereal and yoghurt. Tarhana or tarhana-like products have been enriched or replaced with cereal and pseudocereal. In this research, the applicability of QF in traditional tarhana production were investigated. As a result, it is advisable to replace wheat flour with QF in products such as tarhana, couscous, noodle and pasta formulation for nutritional and sensory properties enrichment. The results suggest that QF can be used in gluten-free tarhana formulations to enhance rheological properties.