1.We noticed an increase in the temperature
of the wheat to 45 0C in parts of the silo during the winter. When
we checked the wheat we couldn’t find any signs of infestation. What may the
reason have been? Can we still use the wheat?
This phenomenon is probably due to self-heating
caused by fermentation. This can occur if the wheat is not moved or
sufficiently aerated during storage. If only a small amount is affected, the
thoroughly mixed wheat can be used (unless the taste and smell are impaired),
but the performance should checked. Unusually short dough properties indicate
heat damage to a larger proportion of the wheat.
2. If the flour has been treated with
enzymes/ ascorbic acid/ bleach, will its properties be maintained during
storage? For how long?
Most enzymes except glucose oxidase and
transglutaminase are very stable in the flour too. In most cases the shelf-life
is restricted by the organoleptic properties of the flour rather than by its
baking performance. Ascorbic acid slowly oxidizes to dehydro-ascorbic acid,
which is the oxidizing agent to which ascorbic acid has to converted anyway
before it has an oxidizing effect. A shelf-life of 6-9 months is no problem.
3. Why does flour milled from wheat of
different ages behave differently when baked, although the age of the flour
itself (i.e. number of days after milling) is identical?
Maturation does not only take place in flour; it
also takes place in the intact grain, although the chemical and biochemical
processes are probably different. Maturation can be observed every year with
the new crop: The optimum dosage of oxidizing agents (maturing agents) is high
when the new wheat is first milled and can be (or has to be) reduced after
longer storage.
4. Is there any additive I can use to
protect flour against insect infestation?
So far there seems to be no such additive. And
there will probably always be an insect species that is not repelled by the
treatment.
5. My flour forms lumps after a few weeks of
storage, especially at the bottom of the bags. What can I do to prevent it?
This may be due to a slightly elevated moisture
level in the flour. The granulation also plays a role in lump formation. Very fine
particles tend to form lumps more readily (semolina is more free-flowing than
wheat flour).
6. I am having problems with the
microbiology of my wheat and fear they will impair the self life of my flour.
What product might help?
If the flour has less than an even 15% moisture the
microorganisms are unable to grow, so they cannot impair the shelf-life. On the
other hand these microorganisms may just be a sign of inadequate cleaning of
the wheat or failure to remove all the bran. If the lipid content of the flour
is also high for this reason, the shelf-life will indeed be impaired. But we do
not recommend treatment with chemical agents such as antioxidants.
The microorganisms may, however, play a role in the
further processing of the flour. Especially if there is a large number of
thermophilic spore formers (Bacillus subtilis,
B. masentericus), some may survive baking and cause degradation of the
crumb of the bread. Preservatives such as propionate, acetic acid and even
vinegar may help.
7. Why does flour go rancid, and how can
this be prevented?
At moisture levels above 15%, flours can go rancid
because of the activity of fat-degrading enzymes. Storage at termperatures
above 20 0C also plays a role in the effectiveness of the enzymes. A
moisture content below 14% reliably prevents hydrolysis of the fat in the flour
because the aw value is then so low that the enzymes are only very slightly
active.
8. How can we avoid rancidity?
The germ and the aleuron layer contain most of the
flour lipids. If both are neatly removed while the germ is kept intact to avoid
release of fat, rancidity will not occur during a reasonable period of storage.
Furthermore, rancidity is triggered by exposure to light, moisture, heat and
oxygen, so any condition reducing these factors also reduces rancidity.
9. The wheat has a strange, musty
smell. What is the reason? Can I use the
wheat? How can I remove the smell?
The smell is probably caused by unsuitable
transportation or storage conditions resulting in mould formation. If the damage
is only superficial, thorough cleaning and milling with a low yield will remove
most of the substance that smells. In the past, attempts have also be made to
mix the grain with active charcoal in order to absorb the substance responsible
for the smell. The charcoal was subsequently removed by sifting.
10. The flour has a strange smell. Where
does it come from? Can I use the flour?
The off-smell may be a carry-over from the wheat
(See question 9), or it may have been caused by unsuitable storage of the flour
itself. There is no viable method for removing the smell from the flour. Adding
it in small amounts to intact flour is probably the only way to use the flour.
11. The bread develops a strange smell
during storage. What may the reason be?
This is probably due to the potato disease. Later on,
the crumb will form slimy strands when broken open.
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