title: Preparation of lactic acid bacteria fermented wheat-yoghurt mixtures.
abstract: BACKGROUND
  Tarhana, a wheat-yoghurt fermented mixture, is considered as a good source of saccharides, proteins, some vitamins and minerals. Moreover, their preparation is inexpensive and lactic acid fermentation offers benefits like product preservation, enhancement of nutritive value and sensory properties improvement. The aim of this work was to evaluate changes of some chemical parameters during fermentation of tarhana, when the level of salt and amount of yoghurt used were varied. Some functional and sensory characteristics of the fi nal product were also determined.
  
  
  METHODS
  Chemical analysis included determination of pH, titrable acidity, content of reducing saccharides, lactic, acetic and citric acid. Measured functional properties of tarhana powder were foaming capacity, foam stability, water absorption capacity, oil absorption capacity and emulsifying activity. Tarhana soups samples were evaluated for their sensory characteristics (colour, odor, taste, consistency and overall acceptability).
  
  
  RESULTS
  Fermentation of tarhana by lactic acid bacteria and yeasts led to decrease in pH, content of reducing saccharides and citric acid, while titrable acidity and concentration of lactic and acetic acid increased. Determination of functional properties of tarhana powder showed, that salt absence and increased amount of yoghurt in tarhana recipe reduced foaming capacity and oil absorption capacity, whereas foam stability and water absorption capacity were improved. Sensory evaluation of tarhana soups showed that variations in tarhana recipe adversly affected sensory parameters of fi nal products.
  
  
  CONCLUSIONS
  Variations in tarhana recipe (salt absence, increased proportion of yoghurt) led to changes in some chemical parameters (pH, titrable acidity, reducing saccharides, content of lactic, acetic and citric acid). Functional properties were also affected with changed tarhana recipe. Sensory characteristics determination showed, that standard tarhana fermented for 144 h had the highest overall acceptability.
authors.affiliation: Department of Food Science and Technology, Institute of Biotechnology and Food Science, Slovak University of Technology, Bratislava, Slovak Republic.
authors.forename: Michal
authors.initials: M
authors.lastname: Magala
authors.affiliation: Department of Food Science and Technology, Institute of Biotechnology and Food Science, Slovak University of Technology, Bratislava, Slovak Republic.
authors.forename: Zlatica
authors.initials: Z
authors.lastname: Kohajdová
authors.affiliation: Department of Food Science and Technology, Institute of Biotechnology and Food Science, Slovak University of Technology, Bratislava, Slovak Republic.
authors.forename: Jolana
authors.initials: J
authors.lastname: Karovičová
mesh_terms: D019342:Acetic Acid / Q000032:analysis; D019343:Citric Acid / Q000032:analysis; D005285:Fermentation / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D019344:Lactic Acid / Q000032:analysis; D012965:Sodium Chloride / Q000494:pharmacology*; D014908:Triticum / Q000737:chemistry*; D015014:Yogurt
chemical_list: D019343:Citric Acid; D019344:Lactic Acid; D012965:Sodium Chloride; D019342:Acetic Acid