Stydy on survival of probiotic bacteria and sensory properties of two probiotic yoghurt during prodcution and storage

Because of many health benefits, production and cosumption of probiotic products was incresead worldwide. Viability of probiotic bacteria and sensory propperties are important factors in quality of probiotic yoghurt. Many factor can affect the sensory property and survival of probiotic bacteric in yoghurt. Thus, the aim of this study was to assess the the viability of probiotic bacteria and sensory properties of two kind probiotic yoghurt. Two kind of probiotic yoghurt named as MY 1821 and ABY3 were made using commercial starter culures according to manufacturer instruction. Viability of probiotic bacteria (lactobacillus acidophilus, bifidibacteria and lactobacillis casei) and sensory properties (flavour, mouthfeel, appearance and texture) of yoghut were assessed during 21-days at 7 days interval. statistical analysis was carreid out using T-test and ANOVA (repeated measure) in SPSS software. P value less than 0.05 was considered as significant. At the end of experiments the number of lactobacillus acidophilus and bifidobacteria were 7.42± 0.04 and 6.90 ± 0.06 log cfu/gr in MY1821 and 6.45 ± 0.11 and 6.16 in ABY3 and the number of lactobacillis casei was 7.55± 0.04 log cfu/gr in MY 1821. population of lactobacillus acidophilus and bifidobacteria decreased by 1.1 and 0.48 log cfu/gr in MY 1821 And 0.89 and 1.38 cfu/gr in ABY3 yoghurts.viability of L. casei also reduced and by 0.55 Log cfu/gr in MY 1821 yoghurt. At the end of experiments the mean score for flavour, mouthfeel, appearance and texture were 21.2± 3.09 , 12.36 ± 1.80, 7.2± 1.1.01, 3.86± 0.35 in MY 1821 yoghurt and 17.6±4.22, 10.73±2.46, 6.66± 0.97 and 3.33± 0.49 in ABY3 yoghurt respectively. The number of probiotic bacteria at the end of storage were above the criteria determined by Iran national standard. The result of sensory evaluation showed that the prepared yoghurt had good to excellent acceptance. Thus using these starter cultures by diary industry is recommended. Because of helth benefits of probiotics, consomption of these products for their high population of probiotic bacteria can improve the public health.