October 30, 2014 - 11:37am
l.sanfranciscensis metabolism
For those interested.
Lactobacillus sanfrancisco a key sourdough lactic acid bacterium : a review
Author(s)
GOBBETTI M. ; CORSETTI A.
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l.sanfranciscensis metabolism
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I'll add it to my copy of:
http://www.amazon.com/Handbook-Sourdough-Biotechnology-Marco-Gobbetti/dp/1461454247
Now, if we could only tell if there's any L. Sf. in our starters!
indeed, if only...
How interesting!
What sticks out to me is the malolactic enzyme, I'm familiar with this one though my home brewing/winemaking experience. This is the enzyme though which malic acid (present in grapes, apples, or other fruit) is convered to lactic acid (a milder acid), sometimes resulting in a bit of diacetyl, which presents itself with a "buttery" flavor (this fermentation is what gives some chardonnay it's butter flavor). I'm going to have to do some experiments with adding apple juice to my lean sourdough breads, to see how the starter metabolizes the juice (or hard cider perhaps). Experiments to come, see if I can tease some buttery mouth feel out of my lean doughs.
Ooh, now I know why my fermenting starter can pick up a "green apple" smell from time to time, the Acetaldehyde on the chart is responsible for that.
I may have to pick your brain, I am looking to get into wine making...
I can often smell diacetyl in my freshly baked bread. But the likely maker of this compound is l.Plantarum.
Ahh. I have smelt those, green apple /grassy acetic notes in my madre when I maintain it wrapped and tied (legato).
I appreciate your input
Where could I get a whiff of all these chemicals so I can familiarise myself with them and the next time I'm sniffing my starter I actually know exactly what I'm smelling?
Dan Lepard, the British author/bread guru, once wrote that he had sent several functioning starters to a lab for testing and at least one of them displayed no Lactobacillus sanfrancisco whatsoever.
Some years ago I experimented with a couple of French varieties of dried starter that came in little packets that were meant for single use as opposed to beginning an ongoing culture. Neither one contained L. sanfrancisco. The one I liked the best contained L. brevis and several yeast varieties.
Most writing on sourdough culture components claim Lactobacillus sanfrancisco as fact or assumption although clearly it is not necessary for a functioning starter. Too bad there is not a cheap home kit to determine the components of my starter, it probably would not change my bread, but it would satisfy my curiosity.
Thanks for the nice chart.
Charles
Good ol' Dan Lepard. I wonder if his testing was done before or after I met him. L.sanfranciscensis was originally classified in Europe as L.brevis subsp. lindneri. Brevis and sf. are very much alike.
I certainly agree that presence of l.sanfran is assumed by some. There are a whole host of LAB that can and do populate the sourdough environment.
Too bad indeed. Curiosity leads to discovery..
It says it becomes pyruvate, then back to lactate. One might think citric acid, or lime or lemon juice, would make your sourdough more sharply acid, but instead it appears transformed to the milder lactic acid.
Mostly the chart is almost gibberish to me, though I understand and appreciate the work that went into making it.