Transcript What is Lactic Acid? - Clark County Food System Council

Fermentation, Probiotics &
the Biome
“God made yeast as well as dough and loves
fermentation just as dearly as he loves vegetation”
Ralph Waldo Emerson
Sauerkraut
We are not a body, but a System:
A Superorganism
• Microbes in our guts also digest in the gut
• They break down the fiber in food into organic
acids that nourish the lining of the intestines
• This is fermentation, breaking down chains of
glucose – into easily absorbed sugar alcohols
• Rather than through bloodstream, this is what
“feeds” those walls
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The Gastrointestinal Tract
• Is populated by billions and billions of
microorganisms, including bacteria and
archaea
• Fermentation is the process that occurs when
these microbes consume and break down
carbohydrates.
• Any carbohydrates in your food that you don't
digest and absorb get passed along to gut
microbes.
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9 out of every 10 Cells is a Microbe
• 99 % of the DNA in our bodies belongs to
microbes
• Our bodies are a collective genome of
microbes
• But our Western diet is reducing the collective
through fat and refined carbs
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In Your Gut: Fermentation Process
• Microbes produce hydrogen, methane and
other gases.
• The gases make the intestines expand; picture
a tube-shaped balloon expanding as it is
blown up.
• The abdominal wall gently expands to
accommodate this, and the gas is eventually
either passed as flatus or absorbed into the
blood stream.
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More on microbes in Gut
• Microbes resist invasion by microbial
“interlopers” – through antibiotic compounds
• They are a secondary line of defense
• They are more agile to threats & opportunities
than we are: exquisitely reactive & fungible
• They are more skilled than we are
biochemically
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What is Fermentation?
• Fermentation is an energy-yielding anaerobic
metabolic process in which organisms convert
nutrients (typically carbohydrates) to alcohols
and acids (lactic acid and acetic acid).
• Yeast perform fermentation to obtain energy
by converting sugar into alcohol.
• Bacteria perform fermentation, converting
carbohydrates into lactic acid.
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What is Zymology?
• The art of studying fermentation is called
zymology or zymurgy.
• Louis Pasteur was one of the first zymologists
and referred to fermentation as “the result of
life without air."
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An ancient biotechnological discovery
• Over 10,000 years ago mankind was producing
wine, beer, vinegar and bread using
microorganisms, primarily yeast.
• Yogurt was produced by lactic acid bacteria in
milk, and molds were used to produce cheese.
• Caves are the perfect environment for a
ferment
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Acid vs Alkaline Ferments
• LACTIC ACID: sauerkraut, olives, pickles, Korean
Kimchi, yogurt, Ghanian Kenkey, Nigerian gari,
Philipine balao bao lao, sourdough bread, Indian idli
& khaman, Ethiopian injera, Western sausages,
preserved lemons, Thai nham
• ALKALINE: Nigerian dawadawa, Ivory Coast
soumbara, Japanese nato
• AMINO ACID: soy sauce, fish sauce, ketchup
• ACETIC ACID: vinegar, kombucha, nata de coco
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What is Lactic Acid?
• The pyruvate molecules from glucose
metabolism (glycolysis) may be fermented into
lactic acid.
• Lactic acid also occurs in animal muscles when
the tissue requires energy at a faster rate than
oxygen can be supplied.
• We know this as “cramping”
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An important generalization
• Fermentation reactions are not peculiar to the
action of yeast but also occur in many other
instances of glucose utilization.
• The production of lactic acid from lactose and
water may be summarized as:
• C12H22O11 (lactose) + H2O (water) → 4
CH3CHOHCOOH
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Nutrient Enhancement
• Fermenting not only preserves food but also
enhances the nutrient content.
• The action of the culture organisms makes the
minerals in cultured foods more readily
available to the body.
• During the fermenting process the bacteria
also produce B vitamins and enzymes that are
beneficial for digestion.
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Lactic Acid Does It
• Lactic acid bacteria create a natural process of growth
and acid production
• Salt and limited air create desirable conditions for the
leuconostocs – a group of less acid tolerant lactic acid
bacteria that grow better at 60°F to 70°F.
• As the leuconostocs grow, they produce flavor
compounds, lactic acid and carbon dioxide creating an
environment that favors more acid tolerant
lactobacilli (grow well above 70°F).
• Lactic acid actually preserves healthy flora throughout
intestine
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Enzymes & Lactic Acid
• Certain carbohydrates: Oligo-saccharides,
Disaccharides, Monosaccharides & Polyols are
short-chain carbohydrates that are
incompletely absorbed in the gastrointestinal
tract, often are sugar alcohols
• Lactic Acid breaks down carbs effectively into
shorter fatty acid chains – “pre-digestion”
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Bacteria: Friend or Foe?
• Skins of fruits and vegetables come complete
with natural bacteria accumulated during the
farming and transportation process. These
bacteria, if allowed to grow, will ferment your
fruits or vegetables
• BUT - some of the present bacteria as well as
bacteria in the surrounding air may not lead to
a tasty finished product.
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Salt & Culture Mechanisms
• Salt and starter cultures such as whey, kefir
grains, and freeze-dried cultures promote the
fermenting process
• They inhibit the growth of undesirable
microorganisms, favoring the growth of
desired Lactobacilli, and in some cases even
adding desirable bacteria to the culturing
process.
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Two Methods Used
• There are several different methods used to
ferment foods – the two main methods are
salt fermentation and lacto-fermentation.
• Most common is layering salt
• Acid production can also be completed by
adding lactobacilli to work in combination
with other lactic acid bacteria
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Salt
• Salt allows the natural bacteria that exist on
the vegetables to do the fermenting.
• A benefit of salt is that it hardens the pectin in
the vegetables leaving them crunchy and
enhancing the flavor.
• Salt pulls out the moisture in food, denying
bacteria the aqueous solution they need to
live and grow except for the desired salttolerant Lactobacilli strains.
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Keep Desirable Strains Active
• Using ingredients such as salt can inhibit the
growth of undesirable microorganisms while
favoring the growth of desired strains of
bacteria.
• By suppressing the growth of other bacteria
and mold, salt provides a slower fermentation
process that is perfect for cultured vegetables
that are to be stored for longer periods of
time.
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Preserved Lemons
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Lemons
Kosher or Pickling salt
Bay Leaves & spices
Using crock & stomping down tool, Tracy will
demo…
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