Author/Authors :
Marhamatizadeh، Mohammad Hossein نويسنده Department of Food Hygiene, Veterinary Faculty, Kazerun Branch, Islamic Azad University, kazerun , , Ehsandoost، Elham نويسنده Department of Food Science and Technology, Young Researchers Club, Kazerun branch, Islamic Azad University , , Gholami، Paria نويسنده Department of Microbiology, Kazerun branch, Islamic Azad University, Kazerun ,
Abstract :
Green Tea is rich in polyphenols and other phenolic compounds that have been widely reported to have beneficial health effects. The objective of present study was to determine the effect of the supplementation of Green tea (Litsea coreana L.) Extract in probiotic milk and yoghurt on post-acidification, total titratable acidity, bacteria counts by two probiotics strains: Lactobacillus acidophilus and Bifidobacterium bifidum during 21 days of storage at 2°C. Green tea extract was added to low-fat sterilized milk at 0.3%, 0.6 % and 0.9 % concentration and inoculated with yoghurt starter to obtain Green tea yoghurts. Similar procedure was applied to prepare Green Tea milk. The results of this study demonstrated the positive correlation between increased bacterial growth and increased Green Tea concentration. Green Tea supplementation positively influenced the initial acidity and the count of Lactobacillus acidophilus and Bifidobacterium bifidum compared with the plain milk and yoghurt (p < 0.05).In the samples containing Lactobacillus acidophilus and Bifidobacterium bifidum, it was observed that increased concentrations of Green Tea extract create a favorable taste in milk and yoghurt. Consumer sensory testing analysis found that green tea milk and yoghurt samples were liked as well or better than the control milk and yoghurt samples. All the results suggest that Green Tea extract promoted the metabolism of lactic acid bacteria in milk and yoghurt.
