Baking & Snack - May 2004 - 63

May 2004

Baking 101: Chemical Leavening
BY CLYDE E. STAUFFER, PH.D.
or more than 5,000 years, bakers
depended on natural methods - fermentation by yeast and bacteria - to
modify dough. The fermentation process
develops appealing flavors and aromas,
while the leavening action caused by the
carbon dioxide (CO2) and ethanol generated by the microorganisms improves eating quality. About 500 years ago, however,
some unsung baker found that sodium bicarbonate, or bakers' soda, could produce
similar leavening results in raising
dough and tenderizing crumb
but without the time-consuming fermentation step.
Sodium bicarbonate reacts
with acids present in food
to form CO2, which expands during baking. Until
the mid-1800s, these acids
either occurred naturally in
food components such as the
lactic acid present in cultured
buttermilk or were added in the
form of cream of tartar (potassium
acid tartrate) or vinegar. At that time,
bakers began seeking other food-grade
leavening acids; the first one used was
monocalcium phosphate monohydrate
(MCP), followed by sodium aluminum
sulfate (SAS), both around 1880.
MCP, like the other food acids mentioned
above, begins to react with bicarbonate in a
batter or dough as soon as it is wetted. SAS,
on the other hand, reacts only slightly at
room temperature but becomes fully active
when the oven raises the internal temperature of the dough or batter. The combination
of these two acids with sodium bicarbonate
produced "double-acting baking powder,"
a staple ingredient in households and retail
bakeries even today. Beginning around
1910, companies began searching for other
leavening acids that would be activated

at various baking temperatures, allowing
product developers to tailor leavening action to the baking cycle, thus improving
the final product characteristics. From this
work, we have the range of phosphate leavening acids available today:
* Anhydrous monocalcium phosphate
(AMCP)
* Dicalcium phosphate dihydrate (DCP)
* Dimagnesium phosphate (DMP)
* Sodium acid pyrophosphate
(SAPP)
* Sodium aluminum phosphate
(SALP)
A number
of other
acidulants

When a
product's volume
must expand
at a given rate and time,
chemical leavening
provides predictable
results.

were explored for applicability in baking, but only one - glucono-deltalactone (GDL) - has proven useful. This
is an internal ester (a lactone) of gluconic
acid. In the batter or dough, it slowly
hydrolyzes, and the gluconic acid group
reacts with bicarbonate to release CO2.

BICARBONATES
Sodium bicarbonate (NaHCO3) is the major CO2 source used today. It is available
in several grades, or particle sizes. In a dry
mix, for example, a larger particle size will
be more stable during storage, while for
most other purposes in baking, the smaller particle size is more quickly dissolved
during dough or batter preparation. The
reaction of the bicarbonate ion (HCO3)

A wide variety of baked foods achieve
their appealing light texture thanks to
chemical leavening.
ASTARIS

May 2004 / BAKERS PRODUCTION MANUAL / 63

Baking & Snack - May 2004

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