PRODUCTION OF PROBIOTIC YOGHURT BY ZIZIPHORA CLINOPODIOIDES ESSENTIALOILS, AND CHEKING THE VIABLITY EFFECT OF THAT UPON LACTOBACILLUS ACIDOPHILUS AND BIFIDOBACTERIM BIFIDUM.

In recent years, the probiotic bacteria, as the food additives, have been introduced into numerous foods, of which the dairy products especially yoghurt has played an important role in carrying these bacteria (such as B. bifidum and L. acidophilus). The purpose of this study, determine the effects of different ziziphora Clinopodioides (50, 100 and 150 micrograms), in two passages after and before incubation, on the growth of two probiotic bacteria (Bifidobacterium bifidum and Lactobacillus acidophilus) in yoghurt produced. The ziziphora Clinopodioides yoghurt was produced by Tamime (standard methods). The products were then examined in terms of sensory method, pH, acidity and microbe counting during the incubator setting period and their respective permanence. The results in statistical–descriptive test were analyzed using SPSS software version 16 system. It was repeated three times, respectively. The sample containing 50 microgram of thyme essential oils had the most survival of probiotic bacteria at the first day of storage and the least survival of probiotic bacteria after 28 days of storage is related to control sample. In the case of essentialoils addition stage (before or after inoculation with probiotic culture), addition of essentialoils before probiotic culture increased the survival of bacteria. Between the added bacteria, the survival of Lactobacillus acidophilus or Bifidobacterium bifidum used separately was higher than the combined samples. The count of Bifidobacterium did not decrease lower than 10 7 CFU/ ml during storage time and the count of Lactobacillus acidophilus during 21 days of storage was 10 7 CFU/ml. the least decrease of pH and increase of acidity was related to sample with 50 microgram of thyme essential oils which's essential oils was added before inoculation with probiotics and in probiotic samples containing both the bacteria and the most decrease of pH and increase of acidity was seen in control samples. The sample with 50 microgram of thyme essential oils which was inoculated with just lactobacillus before adding essential oils had the most syneresis during 28 days of storage at 4 ˚C and control sample had the least syneresis at the same conditions. In general, addition of 50 microgram of thyme essential oils before inoculating with combined probiotic culture was determined as the best treatment.