The effect of addition of kombucha drink on physicochemical, Sensory characteristics and Viability of Probiotic Bacteria of fermented milk

Nowadays, the selection of probiotics has an important role in the development of the country's food industry and the production of probiotic dairy products is the main indicator of this progress on the other hand, the quality, sensory and viability characteristics of probiotics in manufactured products are the main problems of most industrial factories.

the effect of different concentrations of kombucha drink on the viability of Lactobacillus acidophilus, bifidobacterium bifidum, Lactobacillus Rhamnosus was studied and physicochemical and sensory characteristics of fermented milk were measured during 28 days of storing period at 5±1˚C. Different levels of Kombucha tea 0, 5, 10, 15 and 20 ml/L were added to probiotic fermented milk containing L. acidophilus, B. bifidum, L. Rhamnosus bacteria (Cfu/ml 107) .Viability rate of probiotic bacteria, pH, percentages of protein, acidity(Dornic), acetic acid, antioxidant compounds were measured during 3, 7, 14 and 28th of storing period at 4 ⸰C.

Results showed that higher amounts of kombucha cause higher content of protein, acidity, acetic acid and antioxidant activity. The average amounts of theses parameters were respectivly 0.12,0.02, 15.694 and 0.16. however, pH and viability of probiotic bacteria significantly decreased during the storage period(p<0.05) and average amounts of these parameters were respectively0.79 and 0.046, However, the mentioned indices were higher than the acceptable standard of probiotic products.

the addition of kombucha up to 5% could be more effective in improving sensory characteristics. Hence, a treatment containing 5% of kambucha was selected as the best among others.