Impact of Prangos Ferulacea on Some Microbial, Physicochemical and Sensory Properties of Probiotic Low Fat Yogurt Containing Lactobacillus Casei

Background: the prangos ferulacea (pf)–yogurt is atraditional food in iran. this study investigated the effects ofpf on the microbial, physicochemical and sensory propertiesof probiotic yoghurt.methods: pasteurized low fat milk was heated up to 85°c, cooledto 40°c, and then mixed with conventional and lactobacillus caseistarter cultures incubated at 37°c until ph decreased to 4.6. then,the cooked pf was added to yogurt and stored at 5°c for 21 days.acidity, syneresis, probiotic colony count and sensory evaluation ofyoghurt was determined during the storage time. the experimentswere replicated for three times. probiotic yogurt (py) was examinedas the control and probiotic yoghurt containing 10, 20 and 30%prangos ferulacea (pfy) as the samples.results: total titratable acidity of pfys compared to py wasnot significant during 21 days. the syneresis rate of pfy yogurtshowed significant differences compared to py during storagetime (p < 0.001). comparison of the mean scores of sensoryattributes (taste, odor, syneresis, mouth feel and color) of pfyyogurt showed that there were no significant differences withpy. enumeration of lactobacillus casei (logcfu/ml) revealedsignificant differences in pfys compared to py in eachexperimental day (p=0.040). at the end of the storage time (day21), the highest number of l.casei was observed in py and pfy20% and the lowest in pfy30%.conclusion: adding prangos ferulacea (20%) to probiotic yogurtprevented an increase in acidity, a decrease in syneresis rate andan increase in the number of probiotic bacteria during 21 days.results showed that the highest number of probiotic bacteriawas seen in probiotic yogurt containing 20 percent prangosferulacea; probably, the existing fiber and some nutrients inprangos ferulacea promoted the viability of probiotic bacteria.