The microbiology of Greek/Cyprus Trahanas and of Turkish Tarhana: a review of some literature data

Abstract

Greek and Cyprus Trahanas are the most popular fermented milk-cereal products of Greece and Cyprus, and are produced during summer from fresh ewes’, goats’ milk or a mixture of them. Broken wheat is then added to the fermented milk and heated to cook the mixture and then a thick paste is left to cool and cut into small pieces and left to dry (sun or oven drying). In Greek trahanas, fermentation of the lactic acid bacteria Streptococcus lactis, Streptococcus diacetylactis, Leuconostoc cremoris, Lactobacillus lactis, Lactobacillus casei, Lactobacillus bulgaricus and Lactobacillus acidophilus plays the major acid- and aroma -producing roles. A great biodiversity of microorganisms was observed during Cyprus trahanas fermentation. Lactic acid bacteria (LAB) were the predominant group, followed by yeasts. Lactococcus, Lactobacillus, and yeast species contribute greatly to its fermentation. Turkish Tarhana is the dry form of yoghurt-cereal mixture that is produced by mixing cereal flour, yoghurt, baker’s yeast (Saccharomyces cerevisiae) and cooked vegetables, salt and spices followed by fermentation for one to seven days. The fermented slurry is then air-dried and used in soup making. LAB species found in Tarhana fermentation vary depending on the raw materials, fermentation time and techniques used for its production and play an important role in lactic acid and aromatic compounds formation. Lactococcuslactis spp. lactis, Leuconostoc mesenteroides, Lactobacillus acidophilus, Enterococcus durans, Pediococcus spp., Lactobacillus delbrueckii ssp. lactis and Lactobacillus paracasei bacteria played a role during the fermentation of Tarhana dough. Yeasts were mainly represented by S. cerevisiae.