Transcript Potential of Lactobacillus in Northern European cheeses

Potential of Lactobacillus
in
Northern European cheeses
Symposium in Tallinn, Estonia
23-25 April 2007
Session A:
Lactobacillus in Nordic cheese
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Lactobacillus helveticus – enhance flavour production in
cheese
NSLAB – well characterised in many Northern European
cheeses
The metabolism of Lb. plantarum (most probably the
majority of NSLABs) in cheese is influenced by the starter
used
In cheeses with added Lb. helveticus 16 key aroma
compounds has been identified
The proportions and numbers of NSLAB are dynamically
changing during ripening of Estonian cheeses. Most of
the isolates were Lb. paracasei, Lb. curvatus and Lb.
danicus and some have good resistance to acid and bile
salts.
Session A:
Lactobacillus in Nordic cheese
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Lb. rhamnosus, Lb. casei and Lb . fermentum was found
in finish Emmental during ripening, with the first one
dominating.
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The microflora of a Swedish hard cheese was dominated
by NSLAB (Lactobacillus) after 3 weeks of ripening and a
correlation between diversity and aroma was indicated.
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6 different aminopeptidases were found in Lb. paracasei,
specific for Leu-pNA, Lys-pNA and Gly-Pro-pNA
SPA EVENING
Thalasso

sauna
perfect negotiation arena
Massage
- ahh!
Salt chamber
did
Swimming
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you fell asleep?
pool
exercise of the week?
Infrared
sauna
Session B:
Lactobacillus as cheese ripening cultures
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NSLAB do impact on flavour but they are not key drivers
NSLAB cocktails
Remember the potential of NSLABs for functional foods
Lb. paracasei’s does not lyse very much,
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Survive at least 3 h at pH 3 and were resistant to bile salt, but only
few survived at pH 2.
Many of them metabolise citrate and reduce pH in milk.
Lb. helveticus strains isolated from cheese grew better than the
“Laboratory strains”, and they showed no degradation of peptides in
a cheese extract
Calorimetric measurements showed that Lb. paracasei and St.
thermophilus grew better in pasteurised milk than in UHT treated
milk and reconstituted milk
Session C:
Improving bioactivity of cheese
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Focus on the functional properties of cheese for health
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Vehicle for probiotic bacteria
CLA
Bioactive peptides
Lactococcus strains were more inhibited by spice ethanol
extracts than Lactobacillus strains with clove ethanol
extract being the most inhibitive.
H2O2 addition to milk 1 h before starter inoculation
influenced the growth of the starter and the rheological
characteristics of the milk gels.
Session C:
Improving bioactivity of cheese
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Addition of heat-treated Lb. helveticus accelerated breakdown of
phospopeptides in cheese but did not remove them
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Acetone extracts of rosemary, curcuma and savoury had
antibacterial effect against lactic acid bacteria and pathogenic
and spoilage bacteria, but were more inhibitive to the lactic acid
bacteria.
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Amino acids and hydrophilic peptides contribute to savoury
flavour in cheese and the presence of thermophilic Lactobacillus
increases the level of these components
Estonian Spring Experience
City tour with one English and
Swedish speaking guides
o Now we know the Estonians?
Dinner at Eesti Maja, a
traditional Estonian
restaurant
• No reason to visit Mc Donalds!
Session D:
Application of genomics data for
Lactobacillus in the production of cheeses
We are impressed by the possibility of transcriptomics to
study the up and down regulation of the microorganisms,
we started to realise which opportunities we have in the
future. We started to realise that the amount of
frustrations in the future will be reduced!
New nomenclature for the Lb. casei complex has to come.
LTA – Lipoteichoic acids
 Low D-alanylation LTAs allows LTA to function as an
active phage receptor for phage LL-H in Lb.
delbrueckii subsp. Lactis.
 High D-alaynalated LTAs - immunostimulary activities.
 Ca2+ and or Mg2+ binding
 Inhibition of enzyme activities
 Antigenic
Lactobacillus paracasei strains showed inhibition towards
several moulds and Clostridia. Danish strains more
inhibitive towards clostridia than Czech strains
NordOst
www.umb.no/nordost
PhD course
Final Progress of the NordOst network
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Proceedings
5th IDF Conference on Cheese Ripening
www.cheese2008.ch