Other examples of the dextrinization of
starch in ordinary cooking processes are the
crust formed in baking breads and the tasty
brown outside portions of starchy vegetables
which are cooked at a high temperature, as in
frying or baking. The starch in the ready-
to-serve cereals is sometimes partly dex-
trinized in the manufacturing process.
Moist Heat. Starch grains are practically
insoluble in cold water, although they are
rendered slightly soluble if the grains are
mechanically injured or broken by grinding.
This breaks the tough outer layer and re¬
leases the more soluble portion. When
stirred in cold water the starch grains tend
to separate on standing.
On the other hand, when a mixture of
starch and water is heated, the starch grains
absorb water, swell, and form a viscous solu¬
tion. This solution is more or less clear, de¬
pending upon the source of the starch and
[61]
the relative amounts of the two amyloses
present, and does not separate on standing.
As the solution is cooled, the stiffness in¬
creases and gels of varying degrees of firm¬
ness are obtained.
This gelatinizing quality of starch is very
useful in food preparation. Starch puddings
which will hold their shape are prepared by
cooking the correct amount of starch in
liquid. Thick cream sauces used cold to bind
chopped foods into croquettes are soft and
palatable when served hot.
Since the swollen granules of cooked starch
remain suspended in liquids and do not
separate, starch is used in the preparation of
cream soups to hold other material in sus¬
pension. Substances that do not go into solu¬
tion but remain suspended in a liquid in
finely divided particles are called "colloids”
and form colloidal solutions in water.
Starches form colloidal solutions when boiled
in a liquid. This property of starch to
thicken liquids and hold other materials in
suspension is important in many cooked
dishes.
The flavor of raw starch is destroyed by
boiling. Although the digestibility of a
starch mixture is not materially increased by
boiling as compared with cooking at a lower
temperature, the thickening of starch solu¬
tions reaches its maximum at about the boil¬
ing point. This thickening can be obtained
in a double boiler, but a short cooking time
(two minutes) directly over the heat at boil¬
ing temperature insures maximum thicken¬
ing and avoids the danger of the so-called
raw-starch taste, to which many object. The
mixture then may be placed over hot water
to continue cooking or to keep warm.
Thickening Power. It is important in
starch cookery to know the amount of starch
which should be added to the liquid to obtain
' the desired thickness. The same amounts of
the different starches give slightly different
results in consistency. Cereal starches as a
group form firmer gels than root starches
when both are used in the same proportions.
There also are differences among the starches
within these groups, in both the firmness and
the elasticity of the gels formed.
The addition of sugar up to 50 per cent of
the amount of starch makes a more tender
gel but has little influence on the firmness of
the gel formed. More than that amount of
sugar produces a viscous gel.
Page 56
Presented as published in 1935. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
Other examples of the dextrinization of starch in ordinary cooking processes are the crust formed in baking breads and the tasty brown outside portions of starchy vegetables which are cooked at a high temperature, as in frying or baking. The starch in the readyto-serve cereals is sometimes partly dextrinized in the manufacturing process.
Moist Heat. Starch grains are practically insoluble in cold water, although they are rendered slightly soluble if the grains are mechanically injured or broken by grinding. This breaks the tough outer layer and re¬ leases the more soluble portion. When stirred in cold water the starch grains tend to separate on standing.
On the other hand, when a mixture of starch and water is heated, the starch grains absorb water, swell, and form a viscous solu¬ tion. This solution is more or less clear, de¬ pending upon the source of the starch and
[61]
the relative amounts of the two amyloses present, and does not separate on standing. As the solution is cooled, the stiffness in¬ creases and gels of varying degrees of firm¬ ness are obtained.
This gelatinizing quality of starch is very useful in food preparation. Starch puddings which will hold their shape are prepared by cooking the correct amount of starch in liquid. Thick cream sauces used cold to bind chopped foods into croquettes are soft and palatable when served hot.
Since the swollen granules of cooked starch remain suspended in liquids and do not separate, starch is used in the preparation of cream soups to hold other material in sus¬ pension. Substances that do not go into solu¬ tion but remain suspended in a liquid in finely divided particles are called "colloids” and form colloidal solutions in water. Starches form colloidal solutions when boiled in a liquid. This property of starch to thicken liquids and hold other materials in suspension is important in many cooked dishes.
The flavor of raw starch is destroyed by boiling. Although the digestibility of a starch mixture is not materially increased by boiling as compared with cooking at a lower temperature, the thickening of starch solu¬ tions reaches its maximum at about the boil¬ ing point. This thickening can be obtained in a double boiler, but a short cooking time (two minutes) directly over the heat at boil¬ ing temperature insures maximum thicken¬ ing and avoids the danger of the so-called raw-starch taste, to which many object. The mixture then may be placed over hot water to continue cooking or to keep warm.
Thickening Power. It is important in starch cookery to know the amount of starch which should be added to the liquid to obtain ' the desired thickness. The same amounts of the different starches give slightly different results in consistency. Cereal starches as a
group form firmer gels than root starches when both are used in the same proportions. There also are differences among the starches within these groups, in both the firmness and the elasticity of the gels formed.
The addition of sugar up to 50 per cent of the amount of starch makes a more tender gel but has little influence on the firmness of the gel formed. More than that amount of sugar produces a viscous gel.