Raising agents work by incorporating gases into mixtures to create a light, airy texture. There are mechanical and chemical raising agents. Mechanical agents trap air or steam during mixing. Chemical agents release carbon dioxide through acid-base reactions with baking soda or yeast fermentation. The gases expand during baking, causing the structure to set as proteins coagulate around pockets of air.

1. Raising agents
Incorporate a gas into a mixture for a light pleasant texture.
-CARBON DIOXIDE
gases - AIR (combination of gases)
-STEAM (water vapor from liquids of the mixture like milk,
water).
Gases expand when heated, proteins coagulates forming a firm structure,
containing a network of small holes left by expanded gases.
*Mechanical raising agents incorporate air or steam into a mixture
- Sieving flour air becomes trapped between its particles.
- Whisking egg egg white: ovoalbumin (egg protein) stretches
Whole egg + sugar trap air sponges
- Folding and rolling flacky pastry : air trapped between layers
sealed in when baking, it expands , fats melts leaving a space that
is filled with steam, raises the pastry.
- Rubbing in fat and flour air trapped
- Creaming fat + sugar creamed together air trapped mixture
lighter
Steam is produced during baking from liquid present in mixture. Slower
reaction than of gas expansion.
Oven temperature needs to be higher.
Examples: batters (mixture of flour + liquid + egg) pancakes, choux pastry,
flacky pastry.
*Chemical raising agents incorporate carbon dioxide into a mixture
Incorporate by the use of:
- Bicarbonate of soda washing soda + H2O + CO2
Yellowish soda, bitter taste ginger
bread (strong flavored mixture)
-bicarbonate of soda + acid(an acid to counteract taste of an alkali).
. cream of tartar residue color less
Taste less
. tartaric acid greater raise (mild bitter flavour)
. lactic acid by bacteria (scone making)
- baking powder commercially powder ( bicarbonate + acid + starch)
(Absorbs moisture from atmosphere)

2. - Self- raising flour + standard raising agent
- yeast microscopic living plant. Can be dried or fresh
Fermentation from glucose (do not need oxygen)
GLUCOSE CO2 + ALCOHOL (evaporated with heat)
Yeast need source of food (starch or sugar)
feezing temp dormant
Correct temp. 25ª- 29ª more temp yeast destroyed
less temp activity slows down
moisture
Enzymes maltose maltose to glucose
Invertase sucrose to fructose and glucose
Zymase group convert glucose/fructose to ethanol + CO2
Starch amylase maltose maltase glucose zymase
(flour) (enzyme in flour) (enzyme in yeast) (enzyme in yeast)
CO2 + alcohol
Expands evaporates (I don’t need alcohol for the dough, I need it for
wine and beer elaboration)
During baking the dough rises . It sets as the gluten (the 2 proteins) coagulate.
For BREAD:
- flour
- yeast
- liquid
- salt
- fat
Stretching capacity of mixtures
In order for a mixture to “RISE”, it must have the ability to stretch and hold its
shape.
In wheat flour, gluten is form from the proteins present (gliadin and glutenin).
When water is added, it becomes “elastic” as a result.
This gives flour mixtures the ability to stretch.
Different types of wheat flour, produce different amount of gluten (which means
different capacity to stretch), therefore suitable for certain
mixtures.