The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

where Lactobacillus sanfranciscensis get Maltose from in white flour ?

Herbgarden's picture
Herbgarden

where Lactobacillus sanfranciscensis get Maltose from in white flour ?

There is only about one question about San Francisco sourdough that I don't get...

Could somebody please explain to me exactly where and how does Lactobacillus sanfranciscensis get Maltose in white flour from, if there is No Maltose in white flour and there are no enzymes in white flour to produce maltose...(enzymes only activate by sprouting grains, which they call malt then)

But white flour does not have enough active amylase enzymes to digest starch into maltose to provide enough food for Lactobacillus sanfranciscensis... 

So how and where does maltose come from ?

1) Does Lactobacillus sanfranciscensis produce enzymes that digest/break Starch into Maltose ?

2) Or does Candida humilis(the 1 yeast that is in symbiotic relationship with the bacteria) somehow digest/break Starch and turn it into Maltose Lactobacillus sanfranciscensis's food ? (Because this yeast only eats glucose, as far as I know, - or does this yeast eat other sugars too ?)

Does this yeast have enzymes to digest raw starch and turn into Maltose ?

Is there anyone here who can explain to me this ? (Which enzymes exactly produced by who that act on starch ?)

*(And if there were enough amylase enzymes in white flour, then it would turn into a sweet maltose liquid, if held at 55-57C for a few hours, but it does not...) Fresh homemade malt powder, from sprouted grains, does though(because of activated enzymes)

 

Thank you

suave's picture
suave

First of all, there's some β-amylase in the flour - it does not depend on germination.  Second, most of the time a miller will adjust enzymatic activity of the flour to the degree optimal for the fermentation.

drogon's picture
drogon

just to add - most independant UK mills aimed at the smaller/craft baker do not add an additional enzyme/amalyse to their flour.

See https://www.sustainweb.org/realbread/undeclared_flour_additives/ for more details.

 

-Gordon

suave's picture
suave

Ummm, I don't think that's quite what they say.  They talk about fungal amylase, but do not mention malt which is a source of amylases.

PS.  Fungal amylase is likely made exactly the same way as insulin, yet I don't see anyone running around with Real Insulin campaign.

drogon's picture
drogon

... it would be on the label as it's a legal requirement.

Just pointing out that not all mills add stuff to their flour. I have personally collected flour from mills in the past too - watched it come down the chute off the stones, into a sack and into my car. Nothing added there.

-Gordon

BreadBabies's picture
BreadBabies

so I don't know if it's going to answer your question, but it might...

http://www.thefreshloaf.com/node/10375/lactic-acid-fermentation-sourdough

dabrownman's picture
dabrownman

https://blogs.scientificamerican.com/guest-blog/enzymes-the-little-molecules-that-bake-bread/

This will answer all of your question.  Millers in the USA test their white patent flours for essential enzymes and, if they are lacking they are added to the flour at the mill.  This used ti be done with barley malt but many use fugal malt instead today.  The flour label will specify if it added.  Organic flour cannot have added ingredients so it can be in some ways inferior if the enzymes left from the milling are low. Whole grain  flours have plenty of these enzymes so no additions are needed.

suave's picture
suave

Organic flour can be malted as long as malt itself is organic.

kendalm's picture
kendalm

French style breads I did a lot of research about flours and discovered that USA mills almost exclusively use barley malt and you can see that on the label. What I wanted to find was wheat malt to achieve a more characteristic flavor that is so evident when eating bread in France. I even called several labs here including central milling and they said that they just don't do wheat malt. I ended up having to visit beer brewing suppliers to obtain wheat malts and eventually became rather proficient in identifying the difference between malts. Regardless if you've ever added even 1/2 a percent of a diastatic malt to your flour you can see that it has a profound effect on the starches and so I am pretty sure that that most standard white flours have enough additives food for lactobacilli

Norcalbaker's picture
Norcalbaker

herbgarden, This is condensed explanation of why maltose is available:

* all the starch is stored in the endosperm 

* white flour is made from the endosperm

* Between 70% - 80% of the endosperm is starch; 9% - 12% is protein.

* Starch is stored in the endosperm in granular form: large type A and small type B granules.

* When wheat is milled, it damages the starch. The two types of granules are dispersed into the flour. The damaged starch become more accessible to the yeast.

* The starch is in the form of a polysaccharide. A polysaccharide is a fancy word for a long chain of sugar molecules.

* There are two types of polysaccharides in the endosperm: Amylose (20% - 30%) and amylopectin (70% - 80%)

* Yeast is able to metabolize monosaccharides (a simple sugar molecule) immediately.

* But yeast cannot metabolize a polysaccharide. So it must it converted first.

* Maltose and sucrose are both disaccharides (short chain sugar molecules).

* Maltose is a byproduct of amylase--the break down of the polysaccharides.

* Yeast has two enzymes that enable it to convert polysaccharides: maltase (works on maltose, but not sucrose) and invertase (works on sucrose, but not maltose).

* So what this means is yeast has the enzymes to convert a polysaccharide into a monosaccharide. In that process, maltose is produced. There's a lot of polysaccharides available for conversion in white flour, since it's made from the endosperm; and all the starch is stored in the endosperm. 

 

 

suave's picture
suave

* Yeast has two enzymes that enable it to convert polysaccharides disaccharides  : maltase (works on maltose, but not sucrose) and invertase (works on sucrose, but not maltose).

* So what this means is yeast has the enzymes to convert a polysaccharide disaccharides into a monosaccharide. In that process, maltose is produced consumed.  

Norcalbaker's picture
Norcalbaker

in the endosperm. 

Maltose IS a disaccharide.  

The  starch in the endosperm is all polysaccharides and protein. There are no disaccharides present until it's converted. 

yeast can only consume a monosaccharide. So it converts the polysaccharide into a disaccharide (maltose) and then converts the again to a monosaccharide.  That process will leave some disaccharides unconverted.  So the process actually produces disaccharides (maltose).

 

suave's picture
suave

...yeast can only consume a monosaccharide. So it converts the polysaccharide into a disaccharide...

No it does not, enzymes that break up polysaccharide chains come from grain itself, not from the yeast.

 

The first enzyme to take action in bread dough is amylase. Amylase acts on starch (either amylose or amylopectin), breaking the starch chain between adjacent sugar rings. There are two kinds of amylase: α-amylase (alpha-amylase) randomly breaks the chain into smaller pieces while β-amylase (beta-amylase) breaks maltose units off the end of the chain.

Amylase is found in flour. Wheat kernels contain amylase because they need to break starch down into sugar to use for energy when the kernels germinate. The amount of amylase varies with the weather and harvesting conditions of the wheat, so mills generally test for it and add extra or blend flours to get an appropriate amount.

......

Because of amylase, some of the starch in bread dough is broken into maltose, a double-ring sugar composed of two glucose molecules; but fermentation reactions require single glucose rings. Simple sugars like glucose also provide flavor to the bread and participate in browning reactions that occur at the crust during baking.

Norcalbaker's picture
Norcalbaker

Yeast's enzyme invertase is used to convert the disaccharide sucrose into a food source. 

Yeast enzyme maltase is used to convert maltose. 

Catalase is the enzyme in yeast cells that is used all the time in school labs.

Research labs study yeast cell enzymatic activities so much, they can produce yeast cell extracts in the lab without a commercial kit. Scientists constantly study new strains of yeast to profile extracellular enzymatic activity for potential use in industrial applications. 

Enzymes were in fact discovered during a study of yeast. When Louis Pasteur discovered enzymes, he was studying fermentation. Fermentation was assumed to be a spontaneous process. Then Pasteur discovered that fermentation was in fact yeast cells consuming sugars for nourishment through enzymatic activity. 

 

suave's picture
suave

Yes, yeast has enzymes.  Every living thing does.  But that it has enzymes does not mean it has enzymes for every possible task, and degrading polysaccharides just happens to be one of the things it is not capable of doing.

gary.turner's picture
gary.turner

Enzymes break particular joins in the long chain starch.  Maltase will break a glucose-glucose join and catalase will break the glucose-fructose join. If there are not enough alpha and beta amylases available, the process will be slow, but it will happen with only the yeast's enzymes.

Consider the mash processes for lager vs non-lager beer.  Non lager worts are more completely converted to glucose before the enzymes are killed. This beer is fermented much more quickly than the lager which is mashed to keep more long chain starches. The ferment takes much longer (the lager) due to using only the yeast's own enzymes and unless it's Coors or some such develops a more complex flavor profile.

gary

suave's picture
suave

The two critical properties of enzymes are activity and selectivity.  It means that an enzyme is extremely efficient at what they do, often processing many thousands of molecules of the substrate per second, and that an enzyme typically does one thing and one thing only.  So while you are correct in saying that that maltase will break glucose-glucose link it will do it only for one molecule - maltose.  Similarly beta-amylase will break the same 1-4 glucose-glucose linkage, but only from one end of starch molecule and only every other one.  So, while the two enzymes break the same bond, they work on different substrates and give different products.

Catalase is a name typically assigned to an enzyme responsible for handling hydrogen peroxide, at least that's my recollection.

I am no brewer, but my understanding was that mash/wort is filtered prior to the fermentation to remove insolubles, so if you get partially converted soluble sugars it would be medium sized oligosaccharides (dextrins), and those are not fermentable, to the best of my knowledge.  Also, is not lager fermented at lower temperature compared to ale?

gary.turner's picture
gary.turner

Perhaps I misspoke referring to long chain starches when a better term would be long chain or complex sugars.  Yeast's own enzymes are sufficient to break them down enough to feed on.

Quote:
I am no brewer, but my understanding was that mash/wort is filtered prior to the fermentation to remove insolubles, so if you get partially converted soluble sugars it would be medium sized oligosaccharides (dextrins), and those are not fermentable, to the best of my knowledge.
Complex sugars are not fermentable as is; but the yeast's enzymes can still break them down further over time.

Quote:
Also, is not lager fermented at lower temperature compared to ale?
Yes; for the same reason we retard bread fermentation. By slowing fermentation, we allow the enzymes to break down the starch/complex sugars further, changing the flavor profile of the resulting product.

To compare on a simplistic level, ale's flavor profile is mostly determined by the malt roast. Pearl malt provides the highest level of fermentable sugars but little flavor. Darker roasts sweeten the brew at the expense of absorbing less of the hops' bittering agents. Thus, ales using a lot of dark roasted malt will  add some black malt to provide bitterness and counteract the sweetness of the caramelized malt.

Lagers' flavor profile is mostly controlled by the mash process and hops balance (little dark roast malt is used, if any). Darkness is controlled by the length of the boil.

gary

 

suave's picture
suave

Hmmm, I've always thought that the story behind the rise of the lager was that it allowed better control over the microbiology of the fermentation, basically it was the solution to the spoilage which ran rampant in those days.

Complex sugars are not fermentable as is; but the yeast's enzymes can still break them down further over time.

I am sorry but I simply don't believe this to be the case.  Every single book on fermentation tells the same story:  maltotriose is far as it goes, yeast can not touch anything longer.

dabrownman's picture
dabrownman

a and b are increased exponentially by the malting process.  You want as much of both of them to break the bonds in the abundant starches into as much sugar as possible that the yeast will eventually ciovert into the CO2 and ethanol for beer.

For every increase of 18 F in temperature the amylase enzymes work twice as fast.  A amylase works best at 145 to 158 F and b at 131 to 149 F.  Both start to denature at the upper ranges even though they are working the fastest at those temperatures;

This is why many brewers like myself take advantage of these temperatures during the wort process to get as much sugar out of the grain as possible, as fast as possible, by raising the temperature to 143- 145 F and then later to 150 -152 F before taking he temperature to 170 F to denature the amylase enzymes completely before the fermentation process takes place.  How long the temperatures are held at those 3 temperatues are well known to make the wort process as fast and starch conversion to sugar as complete as possible.

Brewing is a fine art like few others and knowing the science helps a great deal - like most things

http://byo.com/hops/item/1543-understanding-enzymes-homebrew-science

Happy brewing

 

Herbgarden's picture
Herbgarden

OK SO,

Some appear to add extra amylase into white flour... but there is Nothing about that that is written on label of my organic White flour... and nothing about extra amylase in the ingredients,

and I think that they might not have added Any extra amylase to this white, only "enrich" it with useless vitamins, in unnatural form and in megadose... as commonly done to white flour...

To test if the white flour has enough amylase to to convert to maltose for enough food for authentic "San Francisco" culture, would be to mix a little with water, and put it at 57C for 2-3 hours, then taste the mixture, - if it not sweet or very very barely sweet... then this white flour Can Not be used for authentic "San Francisco" culture... and needs little tiny pinch of malt powder added to it, before growing your "San Francisco" sourdough culture

Or you can simply take Any Dry Grain, like rye grain, - wash outside with baking soda, soak in chlorinated water for ~2 days, draining and rinsing twice a day, until completely hydrated inside, then put into an Oster blender on lowest setting with minimal amount of water, then use bendy silicon spoon and that round flat steel mesh screen, and separate all or most of the BRAN, - now you have a very fresh mixture of the freshest White Rye flour(+ very very tiny amount of bran, and enough enzymes and vitamins), without Any processing or grinding on a Mill !

Have you realized it is so easy to turn dry grain into pure, fresh, and healthiest flour ever ? Without the damaging grain bran, that clogs up digestive system and is like sharp sandpaper for your intestine walls (there is about 1/2-1/3 of bran in a whole grain, which is hard to separate any other way properly, especially rye)

This way, you can store dry kernels, and make fresh healthy flour mixture without bran, whenever, then ferment it into sourdough and make raw breads