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Conference Paper: Application of FT-IR and flow cytometry to evaluate the effect of sodium chloride on probiotic bacteria
Title | Application of FT-IR and flow cytometry to evaluate the effect of sodium chloride on probiotic bacteria |
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Authors | |
Keywords | FTIR flow cytometry probiotic bacteria |
Issue Date | 2014 |
Publisher | American Society of Animal Science. The Journal's web site is located at http://jas.fass.org |
Citation | Joint Annual Meeting (JAM) of the American Dairy Science Association (ADSA), the American Society of Animal Science (ASAS), and the Canadian Society of Animal Science (CSAS), Kansas City, Missouri, USA, 20-24 July. In the Journal of Animal Science, 2014, v. 92 n. E-Suppl. 2, p. 163-164, abstract no. 0331 How to Cite? |
Abstract | The aim of the study was to investigate the effect of varying sodium
chloride concentrations on cell membrane, viability and
proteolytic activity of probiotic bacteria. Reconstituted skim
milk was inoculated with Lactobacillus acidophilus at varying
salt concentrations (0-10% NaCl) and pH levels (4.0, 5.0
and 6.0) and ACE-inhibitory activity and proteolytic activity
were determined. Additionally, the effects of NaCl reduction
and its substitution with KCl on cell membrane of certain probiotic
bacteria (Lb. acidophilus, Lb. casei and B. longum) and a pathogenic bacterium, Escherichia coli were investigated
using Fourier transform infrared spectroscopy (FT-IR). A critical
NaCl concentration that inhibited the growth of E. coli
without significantly affecting the growth of probiotic bacteria
was determined by monitoring cell growth and FT-IR spectra.
To evaluate the effect of substitution of NaCl with KCl, substitution
was performed at critical total salt concentration at
varying concentrations (0%, 25%, 50%, 75% and 100% KCl).
Furthermore, the effects of varying NaCl concentrations on viability,
membrane integrity and metabolic activity of these probiotic
bacteria were studied using conventional technique and
flow cytometry. The findings revealed that in Lb. acidophilus
degree of proteolysis increased with higher salt concentration
at pH 5.0 and 6.0 and ACE-inhibitory activity was highest at
pH 5.0 at all salt concentrations. Fourier transform infrared
spectroscopy results demonstrated significant shifts occurring
in amide-I and amide-III regions when Lb. acidophilus was
subjected to varying salt concentrations. Further, the conventional
technique revealed that 2.5% was the critical level of
NaCl to inhibit the growth of E. coli without significantly affecting
the growth of most probiotic bacteria. The FT-IR analysis
also highlighted the changes that occurred mainly in amide
regions on increasing NaCl concentration from 2.5 to 3% in
most bacteria. The findings suggest that 50% substitution of
NaCl with KCl at 2.5% total salt could inhibit E. coli, without
affecting the probiotic bacteria. Lastly, the observations from
conventional culture technique were compared with the findings
from flow cytometric analysis on metabolic activities of
the cells and it was revealed that there was a correlation between
culturability and dye extrusion ability of Lb. casei and
B. longum. However, a certain population of Lb. acidophilus
was viable as per the plate count method but the efflux activity
was compromised. The metabolic activity of Lb. casei was
found to be highest among the three probiotic bacteria. |
Description | Conference Theme: Linking animal science and animal agriculture: Meeting the global demands of 2050 Graduate Student Competition: ADSA Dairy Foods Oral |
Persistent Identifier | http://hdl.handle.net/10722/205071 |
ISSN | 2023 Impact Factor: 2.7 2023 SCImago Journal Rankings: 0.764 |
DC Field | Value | Language |
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dc.contributor.author | Shah, N | en_US |
dc.contributor.author | Gandhi, A | en_US |
dc.date.accessioned | 2014-09-20T01:20:00Z | - |
dc.date.available | 2014-09-20T01:20:00Z | - |
dc.date.issued | 2014 | en_US |
dc.identifier.citation | Joint Annual Meeting (JAM) of the American Dairy Science Association (ADSA), the American Society of Animal Science (ASAS), and the Canadian Society of Animal Science (CSAS), Kansas City, Missouri, USA, 20-24 July. In the Journal of Animal Science, 2014, v. 92 n. E-Suppl. 2, p. 163-164, abstract no. 0331 | en_US |
dc.identifier.issn | 0021-8812 | - |
dc.identifier.uri | http://hdl.handle.net/10722/205071 | - |
dc.description | Conference Theme: Linking animal science and animal agriculture: Meeting the global demands of 2050 | - |
dc.description | Graduate Student Competition: ADSA Dairy Foods Oral | - |
dc.description.abstract | The aim of the study was to investigate the effect of varying sodium chloride concentrations on cell membrane, viability and proteolytic activity of probiotic bacteria. Reconstituted skim milk was inoculated with Lactobacillus acidophilus at varying salt concentrations (0-10% NaCl) and pH levels (4.0, 5.0 and 6.0) and ACE-inhibitory activity and proteolytic activity were determined. Additionally, the effects of NaCl reduction and its substitution with KCl on cell membrane of certain probiotic bacteria (Lb. acidophilus, Lb. casei and B. longum) and a pathogenic bacterium, Escherichia coli were investigated using Fourier transform infrared spectroscopy (FT-IR). A critical NaCl concentration that inhibited the growth of E. coli without significantly affecting the growth of probiotic bacteria was determined by monitoring cell growth and FT-IR spectra. To evaluate the effect of substitution of NaCl with KCl, substitution was performed at critical total salt concentration at varying concentrations (0%, 25%, 50%, 75% and 100% KCl). Furthermore, the effects of varying NaCl concentrations on viability, membrane integrity and metabolic activity of these probiotic bacteria were studied using conventional technique and flow cytometry. The findings revealed that in Lb. acidophilus degree of proteolysis increased with higher salt concentration at pH 5.0 and 6.0 and ACE-inhibitory activity was highest at pH 5.0 at all salt concentrations. Fourier transform infrared spectroscopy results demonstrated significant shifts occurring in amide-I and amide-III regions when Lb. acidophilus was subjected to varying salt concentrations. Further, the conventional technique revealed that 2.5% was the critical level of NaCl to inhibit the growth of E. coli without significantly affecting the growth of most probiotic bacteria. The FT-IR analysis also highlighted the changes that occurred mainly in amide regions on increasing NaCl concentration from 2.5 to 3% in most bacteria. The findings suggest that 50% substitution of NaCl with KCl at 2.5% total salt could inhibit E. coli, without affecting the probiotic bacteria. Lastly, the observations from conventional culture technique were compared with the findings from flow cytometric analysis on metabolic activities of the cells and it was revealed that there was a correlation between culturability and dye extrusion ability of Lb. casei and B. longum. However, a certain population of Lb. acidophilus was viable as per the plate count method but the efflux activity was compromised. The metabolic activity of Lb. casei was found to be highest among the three probiotic bacteria. | - |
dc.language | eng | en_US |
dc.publisher | American Society of Animal Science. The Journal's web site is located at http://jas.fass.org | - |
dc.relation.ispartof | Journal of Animal Science | en_US |
dc.rights | Journal of Animal Science. Copyright © American Society of Animal Science. | - |
dc.subject | FTIR | - |
dc.subject | flow cytometry | - |
dc.subject | probiotic bacteria | - |
dc.title | Application of FT-IR and flow cytometry to evaluate the effect of sodium chloride on probiotic bacteria | en_US |
dc.type | Conference_Paper | en_US |
dc.identifier.email | Shah, N: npshah@hku.hk | en_US |
dc.identifier.authority | Shah, N=rp01571 | en_US |
dc.description.nature | published_or_final_version | - |
dc.identifier.hkuros | 240539 | en_US |
dc.identifier.volume | 92 | - |
dc.identifier.issue | E-Suppl. 2 | - |
dc.identifier.spage | 163, abstract no. 0331 | - |
dc.identifier.epage | 164, abstract no. 0331 | - |
dc.publisher.place | United States | - |
dc.identifier.issnl | 0021-8812 | - |