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Viability of two Iranian isolated species of bifidobacteria in Doogh
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E Ahmadi   , R Mohammadi , M Rouhi , AM Mortazavian * , K Khosravi-Darani , M Shandnush |
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Abstract: (9080 Views) |
| Backgrounds and Objective:Viability of probioticmicroorganisms in the final product is the most important qualitative parameter. These organisms show poor viability incommercial products especially in fermented dairy products.The aim of this study was to assess the interactive effects of two Iranian native strains of Bifidobacterium (Bifidobacteriumanimlis spp. lactisPTCC 1631 and Bifidobacteriumbifidum PTCC 1644), sequential inoculation (inoculation of probiotics before or after fermentation) and final pH of fermentation (pH4.5or 4.2) on biochemical, microbiological, and sensory characteristics of Doogh.
Materials and methods:The Bifidobacterium strains used in the study included Bifidobacteriumanimlis spp. lactisPTCC1631 (Persian Type Culture Collection-Iran) and Bifidobacteriumbifidum PTCC 1644obtained from microbial culture stock of ‘Department of Drug and Food Control’ (Tehran University Culture Collection Center, Tehran, Iran).Doogh was prepared with yogurt starter culture (YF-3331)andBifidobacterium strains.pH, titrable acidity, redox potential, fermentation time, and viability of probiotic organisms were analyzed during fermentation and over the refrigerated storage period (21 days at 5°C).Also, the sensory attributes of treatments were determined at the end of fermentation.Experiments were performed in triplicate and the comparison of the means was done using ANOVA test in significance level of 0.05 (p<0.05) from Minitab software.
Results:The longest fermentation time was observed in treatmentsthat bifidobacteria was cultured with yogurt starter bacteria and incubated at 40°C until final pH4.2. The greatest survival of Bifidobacterium strains was determined in BlY-40-4.5 treatment (whenB.animlis spp.LactisPTCC 1631 strain was co-cultured with traditional yogurt starter bacteria at incubation temperature of 40°C and final pH4.5)in which B. animalis spp. lactis PTCC 1631 survived 8.69 log cfumL-1. The viability of B. animalis spp. lactis PTCC 1631 was significantly more than B. bifidum PTCC 1644. Alsofinal pH 4.5 rather than to pH 4.2 led toincrease the viability of bifidobacteria strainsin similar probiotic organisms.
Conclusion:The variables including the type of bifidobacterium species, final pH, and sequence of probiotic inoculation significantly affected viability ofbifidobacterium species at the end of fermentation and during refrigerated storage.In general, the count of two species of Iranian native bifidobacteria in all treatments at the end of fermentation and throughout the storage time was more than 6.00 log cfu mL-1 per milliliter of Doogh. Therefore, the survival of this strain considerably was higher than the commercial probiotic starter cultures.
Keywords:Bifidobacteriumanimalis, Bifidobacteriumbifidum, Probiotic, Doogh, Viability |
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| Keywords: Bifidobacteriumanimalis, Bifidobacteriumbifidum, Probiotic, Doogh, Viability |
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Full-Text [PDF 322 kb]
(3783 Downloads)
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Article type: Research |
Subject:
Food Science
Received: 2013/02/19 | Accepted: 2013/11/19 | Published: 2013/11/19
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