10. Changes in Milled Rye
Products
10.1. Milling Technology
The tendency found in rye for the proportions of the substances
contained in the grains to change in relation to each other naturally affects
the milling properties, although this is less evident with wholemeal products.
Higher crude protein levels are often thought to coincide with a lower flour
yield.
Larger proportions of swelling substances change not only the ratio of
swelling substances to starch but also the separability of the endosperm from
the outer layers. This may result in milled products with a higher mineral
content at the same degree of extraction. However, the overall mineral content
has changed little in recent years.
10.2. Baking Technology
From the point of view of baking technology the following changes in
rye as a raw material have occurred in recent years:
• higher Falling Numbers of the flour;
• higher temperatures at the gelatinization peak of the Amylogram;
• higher maltose values;
• increased dough yields;
• less uniform dough properties;
• less specific inflation, and thus
• reduced volume yields.
In the bread this led to changes in the elasticity and pressure
resistance of the crumb from well leavened and soft to less well leavened and
rather stiff. The crumb also lost some of its moisture and good keeping
properties.
The slightly higher dough yields and the addition of water-binding
substances (e.g. hydrocolloids or wheat gluten) made it possible to compensate
for this up to a point, but the properties of the crumb nevertheless shifted in
the direction of tough and rubbery rather than moist and soft.
A change in viscosity is also noticeable in the pre-doughs and sponge
doughs. Whereas dough yields of 150 often used to be recommended for sour
dough, rye pre-doughs with dough yields of 160 are now considered too firm. If
sour doughs were still made according to the earlier recommendations, most
mixing machines would be unable to achieve a homogeneous mixture.
The figure has therefore been raised to a dough yield of about 180 or
more. Nowadays, dough yields are chosen on the basis of operating procedures
such as lifting of the dough out of the mixer by hand or pumping of the sour.
However, the water content has relatively little influence on the reactions in the
sour dough. The main factors are the temperature of the dough and the
properties of the raw materials. Flavour development is also reduced, probably
because of changes in the properties of the substrate or reduced enzyme action,
especially in the case of ryes with high Falling Numbers.
Changes similar to those in flours are also found in whole meal
products. Even when large proportions of wholemeal rye flour are used, too much
water is often added to the doughs in spite of their high water-binding capacity;
this results in a very moist crumb or poor crumb elasticity. This is also the
case if over-large amounts of water-binding additives are used, such as
hydrocolloids or wheat gluten. Here too, more attention should be given to the
properties of the dough and the swelling or mixing curves of the raw materials.
The necessity for greater swelling of the pre-doughs is also apparent
when rye meal is processed. In the case of coarse meal, especially, the
percentages have had to be increased, for example in the brew. If the process
is unsuitable, for example if the dough is kept warm too long, undesirable
fermentation may take place as a result of spontaneous reactions and greatly
impair the taste of the bread.
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