
product. However, most of the leavening gas should
be reserved for release at the proper time during
baking in order to achieve the total volume desired.
0018 A number of factors affect the proper time for
release of gas during baking. Product size is certainly
important. A small product will heat, and the struc-
ture will set, faster than a larger product. Oven
temperature obviously affects the rate at which a
product’s temperature rises to the point of setting
the structure. Other ingredients in the formula can
affect the temperature at which a product sets. The
amount of time to mix fully a dough or batter and the
time required to form or deposit the product to be
baked will influence the time at which the leavening
acid should react with the baking soda.
0019 The manufacturers of leavening acids have at-
tempted to meet all the diverse needs of the house-
hold, institutional and large-scale wholesale baker by
developing and marketing products with a wide range
of ‘reaction rates.’
0020 Some materials have essentially no delay in their
reaction with baking soda. They react as soon as they
dissolve in the water present in the formula; the soda
has probably already dissolved. These materials
include the lactic acid in sour milk or buttermilk,
cream of tartar, and MCP monohydrate.
0021 Anhydrous monocalcium phosphate (AMCP) has a
time delay, which, although relatively short, does
allow time for preparing doughs and batters for
baking. A major use for AMCP has been self-raising
flour, which is often used to prepare baking powder-
type biscuits. The time delay of AMCP allows suffi-
cient time for mixing, rolling, and cutting the dough
prior to baking.
0022 Manufacturers of SAPPs have been able to vary the
amount of time delay of these leavening acids from a
few minutes to as much as an hour or more. This is
done by controlling the conditions under which the
SAPP is manufactured.
0023 SAS, SALP, and dicalcium phosphate dihydrate
(DCP) are basically heat-triggered leavening acids.
They have essentially no reaction with soda until the
temperature of the product is raised by the heat of
baking. In some baked products, this delay may be
too long, and SAS, SALP, and DCP perform better
when used in combination with a faster-acting
leavening agent such as MCP or AMCP. Of course,
all leavening agents are essentially ‘heat triggered,’
since they dissolve and react with soda faster as the
temperature of the dough or batter increases. Never-
theless, the term ‘heat triggered’ is usually reserved
for those materials that have an almost indefinite time
delay until the temperature rises to a certain point, in
contrast to those leavening agents that are both time
and temperature triggered.
0024Glucono-d-lactone (GDL) does not fit any of the
above categories of no delay, time delay, and tempera-
ture triggered. GDL reacts continuously, but slowly,
with baking soda. The speed of reaction, of course,
increases with temperature and becomes quite rapid
during baking. The steady release of carbon dioxide
in a dough containing GDL is very similar to the
release of carbon dioxide by yeast in a fermenting
dough. Therefore, GDL has been popular in the
development of chemically leavened bread.
0025The rates of reaction of commonly used leavening
acids are listed in Table 2.
0026Ionic effects of leaveners Although the primary
function of chemical leavening systems is to leaven,
or raise, a product, leavening agents can also affect
characteristics of doughs, batters, and the finished
baked product. These effects are due to reactions
between the leavening agents and components (par-
ticularly starch and protein) of the dough or batter.
These are called ‘ionic’ effects, since the leavening
agents dissolve in the water of the dough or batter
and dissociate into positive cations and negative
anions. In some cases, it is the cation (such as calcium
ions) that is responsible for the observed effect. In
other cases, it is the anion (such as pyrophosphate)
that causes a change in the dough, batter, or finished
product.
0027The calcium and aluminum cations in phosphate-
based leavening acids provide more resiliency to cake
products than the sodium cation in other phosphate-
based leavening agents. Therefore, if resiliency is a
property desired in a cake product, the formulator
may choose a leavening system containing calcium
and/or aluminum ions. Calcium ions tend to stiffen
doughs and thicken batters; they also tend to dry out
moist or slightly sticky doughs. These properties of
doughs and batters are important considerations in
handling and processing, particularly in high-speed,
automated commercial bakeries. (See Bread: Dough
Mixing and Testing Operations.)
tbl0002Table 2 Rates of reaction with baking soda for commonly used
leavening acids
Leaveningacid Rate ofreaction
Cream of tartar Rapid
Monocalcium phosphate monohydrate Intermediate
Anhydrous monocalcium phosphate Intermediate (slower)
Sodium acid pyrophosphates Slow
Sodium aluminum phosphate Very slow
Sodium aluminum sulphate Very slow
Dicalcium phosphate dihydrate Very slow
Dimagnesium phosphate Slow
Glucono-d-lactone Slow
3488 LEAVENING AGENTS