Data Sheet
Supplies: The Basic Recipe
1/3 cup flour |
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You should have several containers of pancake
batter, each missing either eggs or leavening. First, consider the
batter without egg. Record the amount of egg added to each batch,
and the resultant pancake qualities (height, taste, texture, consistency
of batter, etc.).
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Now, add a variable amount of baking powder
to the batter missing leavening.
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Using your knowledge of the effects of
eggs and leavening, design a mix of batter to produce the “perfect” pancake!
Record your ingredient list below:
Things you’ve always wanted to know (or might have wondered) about pancakes and baked goods:
How does baking powder leaven goods?
Carbon dioxide bubbles are generated whenever water is poured over a dry acid and alkali mixture. Baking powder is a blend of acid (calcium acid phosphate, sodium aluminum sulfate, or cream of tartar) and alkali (sodium bicarbonate, a.k.a. baking soda). Baking powder also contains a ground dry starch (corn starch) to absorb moisture from the air and prevent premature reactions from occuring. "Double-acting" baking powder produces a small reaction first, which forms many small gas cells in the batter. Cream of tartar (KHC4H4O6) and monocalcium phosphate (CaH4(PO4)2) are fast-acting acid salts. Sodium aluminum sulfate (Na2SO4 Al2(SO4)3) is a high-temperature component.
The chemical reaction is:HA + NaHCO3 ---> CO2 + H2O + Na+ + A-
The gas generated upon the addition of water (CO2) creates small air pockets within the dough or batter. When the dough or batter is placed on a hot griddle on in an oven, it rises. First, the heat releases additional carbon dioxide from the baking powder. Second, the heat expands the trapped gases and creates steam.NaHCO3 is baking soda
HA is the acid component. For example, tartaric acid is H2C4H4O6.
CO2 is carbon dioxide gas.
By the way - if the batter is mixed for too long, the excess blending can cause the premature formation and escape of the carbon dioxide that is needed for leavening the pancakes.
What prevents baked goods from collapsing back to their original size once their leavening gas escapes or cools?
Baked goods remain firm because the heat of the oven or griddle coagulates* the protein and gelatinizes the starch in the batter or dough. If it were not for this action, the weight of the food's mass would cause many of the air pockets that were formerly supported by the pressure of the carbond dioxide, steam, or hot air to collapse.
*Coagulate: (to cause) to change from liquid
to a more solid state.
How does the choice of liquid affect the dough?
Bread made with water has a chewier texture and crisper crust than one made with milk. However, milk helps produce a more delicate texture and, because of its protein and sugar content, a deeper-hued crust.
What is the function of sugar in baked goods?
Sugar can make bread more tender because it postpones protein coagulation and thus allows the dough or batter to swell to a greater volume before heat stabilizes the structure. Also, heat will caramelize the sugar and give pancakes a golden brown color.
What is the function of egg in baked goods?
Milk and egg proteins coagulate into solid filaments when heated and so
contribute to the structure of the baked product. Without the support
given by heat-coagulated egg protein, popovers and cream puffs would not
maintain their puffed-up shapes. Eggs yolks also contain fat.
The fat tenderizes the product by separating starch granules from coagulated
protein. Finally, the fat content in a bread slows down moisture
loss, and thus it will not go stale as quickly.
For more information about food and food chemistry,
please see:
Howard Hillman, Kitchen Science, Houghton
Mifflin Company, 1989.
Harold McGee, On Food and Cooking, Scribner,
1984.