Improving the Viability of Probiotic Bacteria in Yoghurt by Homogenization
Hamid Reza Nikbakht
MetadataShow full item record
© 2015 Wiley Periodicals, Inc. In this study, the effect of homogenization pressures (100, 150 and 200 bar) at 50, 60 and 70C and stages (1 and 2) on viability of probiotic bacteria was investigated. The milk used for producing yoghurt samples was homogenized at 100, 150 and 200 bar at 50, 60 and 70C, then heated at 85C for 30min. After cooling milk to fermentation temperature (42C), it was inoculated with mixture starter culture ABY-1 and incubated. During fermentation, pH dropped until it reached 4.5. After fermentation, yoghurt samples were held in refrigerator. Viability of Lactobacillus acidophilus and Bifidobacterium lactis was determined during a 21-day cold storage (4C). The results of this study showed that with increasing pressure, temperature and stages of homogenization, viability of probiotic bacteria increased during storage (P < 0.05). Practical Applications: The viability of probiotic bacteria in probiotic products is so important; and nowadays, it is also considered by consumers. Probiotic yoghurt is one of the most widely used probiotic dairy products around the world, and therefore finding an efficient and practical way to produce it with the highest viability of the probiotic bacteria seems necessary. Homogenization is one of the most important steps in yoghurt production, and temperature, time and stages of homogenization are three main factors in this unit operation. In this study, by changing the homogenization conditions, positive results were found to produce yoghurt with the desirable viability of probiotic bacteria, so that by simultaneously increasing the homogenization temperature, time and stages, the probiotic viability improved during fridge storage.