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Indexed/Abstracted in: EMBASE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 0,246
Online ISSN 1827-160X
Selwal K. K. 1, Selwal M. K. 2
1 Department of Biotechnology, DCR University of Science and Technology, Murthal, Haryana, India;
2 Department of Biotechnology, Kurukshetra University, Kurukshetra, Haryana, India
AIM: Commercial exploitation of probiotic and starter cultures depends upon the preservation technologies. Freeze drying is an important technique employed for preservation of starter cultures. So the present investigation is designed to study the effect of freeze drying technique on the probiotic potential of Lactobacillus acidophilus NCDC 15 culture before and after freeze drying.
METHODS: The cell biomass was produced in milk based medium, harvested and mixed with a cryoprotective agent comprising skim milk, sucrose, monosodium glutamate and gelatin. The cell biomass along with cryoprotective agent was freeze dried with a pressure of 50-100 mtorr for 24 h at 40 °C. The in vitro probiotic properties tested comprising acid and bile tolerance, cell surface hydrophobicity and antimicrobial activity against pathogenic cultures.
RESULTS: Acid and bile tolerance test exhibited that 2.5 and 2.4 log cfu/mL reduction in cell counts took place after freeze drying respectively. The culture tolerated different acid and bile concentration without significant loss of viability. Further, no significant change in cell surface hydrophobicity and antimicrobial activity was observed before and after freeze drying. The results provided evidence that no significant effect has been observed on the probiotic properties of culture after drying.
CONCLUSION: This study proves the retention of important probiotic properties of L. acidophilus culture after freeze-drying and the dried culture could be utilized in dairy industry for the manufacture of variants of fermented milk products.