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 , , Davanyan Mohaghegh، Mohammad نويسنده Department of food hygiene, Veterinary Faculty, Kazerun Branch, Islamic Azad University, Kazerun, Iran ,
Abstract :
The present study was designed to investigate the effect of olive leaf extract on Growth and viability of Lactobacillus acidophilus and Bifidobacterium bifidum in milk and yoghurt during 21 days refrigerated storage. In order to determine the effect of different doses of olive leaf extract on growth and viability of probiotic bacteria in milk and yoghurt, first lyophilized bacteria Lactobacillus acidophilus was added to 1 liter of low fat sterilized milk and was considered as control. Olive leaf extract at the concentrations of 0.2, 0.4 and 0.6% were added to the samples and incubated until acidity reached 40 °Dornic and then left in refrigerator. Similar procedure was applied to the bacteria Bifidobacterium bifidum. The produced samples were then examined in terms of pH, acidity and microbial count during the incubation period, and permanence. The number of Lactobacillus acidophilus and Bifidobacterium bifidum in olive leaf milk and yoghurt were significantly higher than those in the control milk and yoghurt. The results indicate the positive correlation between increased bacterial growth and increased olive leaf concentration. In the samples containing Lactobacillus acidophilus and Bifidobacterium bifidum, it was observed that increased concentrations of olive leaf extract create a favorable taste in milk and yoghurt. The samples with 0.6% olive leaf in milk and yoghurt had greater viscosity than the other samples investigated. This research will create a market potential for a range of new health based food to maintain optimal human health. This experiment is the first attempt to produce fermented dairy product with olive leaf extract.
