Raising

Agents

EVIDENCE ONE:
A) Define ‘raising agents.’
B) Name the three major raising agents and describe how they work.
Answers:
a) Raising agents is also known as leavening agents are substances that cause dough to rise
and to become light and porous.
b) The three major raising agents are:
● Air: is trapped mechanically in batters and doughs when whole eggs, egg whites
or egg yolks are beaten and whipped into a foam that is combined with other
ingredients to form a batter. It can also be incorporated by folding and rolling
dough, by creaming fat and sugar together or by simply beating batters.
● Steam: (water in a gaseous state) steam is a major raising agent in baked
products. The amount of leavening possible with steam depends on the ratio of
flour to water in the batter of the dough. Yeast products expand considerably
because a large amount of water produces a great deal of steam. Steam from water
in eggs provide over half the leavening gas in sponge cakes.
● Carbon dioxide(co2): (CO2) Carbon Dioxide is incorporated into mixtures in two
ways that is using chemical raising agents - such as bicarbonate of soda or baking
powder. Using biological raising agents - from the fermentation of yeast. Carbon
Dioxide gas is released into the dough and when heated the gas expands the
appearance of the product. The bubbles of carbon dioxide add air to the mixture,
which is then baked, and the air bubbles become locked into the protein structure
of the sponge creating the fluffy crumb.

Evidence 2:
Using illustrations explain three ways to introduce air into flour mixtures.

Answers:
Three ways to introduce air into flour mixtures are:
Adding eggs: egg whites will always incorporate air into a flour mixture. Sometimes they are
beaten to a foam before they are added, but even just stirring an egg white with a fork will aerate
your mixture.

Sifting: the most common and easiest way to introduce air into a flour mixture is by sifting the
flour. You can easily substitute a fine-meshed metal colander for a sieve, shaking it lightly from
side to side to sift the flour. Once the flour is sifted, measure it without tapping the measuring
cup and allowing the flour to settle down again.

Folding: you can also trap air in the flour mixture by folding the batter repeatedly. Place all your
heavy ingredients in the bottom of the bowl and put lighter ingredients on top. Cut straight down
through the mixture to the bottom and up again with a rubber spatula. Rotate the bowl as you do
this. After a while, the ingredients will be mixed and airy, all in the same process. After this is
done, finish with the rest of your preparations and do not let the mixture linger too long before
placing it in the oven.

EVIDENCE THREE:

a. What is baking powder?

Answers:
 a) Baking Powder: Baking powder is a dry chemical leavening agent and is produced
commercially. It usually consists of bicarbonate of soda, acid sodium pyrophosphate, acid
calcium phosphate and a starch for example rice flour. Baking powder is used to increase
the volume and lighten the texture of baked goods.  It works by releasing carbon dioxide
gas into a batter or dough through an acid-base reaction, causing bubbles in the wet
mixture to expand and thus leavening the mixture.
b) The best raising agent for the following:
● Scones-baking powder or yeast

● Gingerbread- baking soda

● Bread-yeast

EVIDENCE FOUR:
Too much baking powder was added during the preparation of some tea breads.
State four results to expect.

Answers:
Four results to expect when too much baking powder is added to tea breads are:
● Taste: Too much baking powder can cause the batter to be bitter tasting. The taste
of the baking soda will linger about.
 ● Structure: It can also cause the batter to rise rapidly and then collapse. Cakes will
have a coarse, fragile crumb with a fallen center.

● Texture: Too much baking powder results in a tough cake that has poor volume
and a compact crumb.
● Appearance: adding too much baking soda can cause cakes to get brown quickly
before it is completed.

EVIDENCE FIVE:
a) What is the importance of:
● Temperature
● Moisture
● Sugar to yeast
b) Distinguish between quick and double acting baking powder.

Answers:
a) The importance of:
 ● Temperature: If the temperature is too high the yeast cells are destroyed, if too low the
action is slowed. When heated, the gas that is trapped within the product expands. This
rising results in a light and airy texture within foods.
● Moisture: The action of moisture creates a reaction with the raising agent to produce gas
bubbles. Gas bubbles then become set in a mixture and provide a soft sponge like texture.
Moisture is provided by the liquid in the dough; this should be at the correct temperature.
These bubbles expand during the cooking process and causes the baked item to rise,
providing a fine, delicate result.
● Sugar to yeast: Sugar provides “food” for yeast, which converts it to carbon dioxide and
alcohol. Sugar enhances bread flavor. It gives the crust a golden color and improves the
crumb texture. Yeast can use oxygen to release the energy from sugar in the process
called "respiration". So, the more sugar there is, the more active the yeast will be and the
faster its growth. As the yeast feeds on the sugar, it produces carbon dioxide. With no
place to go but up, this gas slowly fills the bread causing it to rise. Carbon dioxide
from yeast fills thousands of bubbles in the dough.

b) Quick-acting baking powder contains acids or acid forming ingredients that are readily
soluble and with the addition of liquid react with baking soda at room temperature. These are the
phosphate containing powders. When quick acting baking powders are used, the product must be
quickly mixed to prevent excessive loss of leavening gas before baking. The gas must be
available during baking to produce the desired effect. If too much gas is lost before baking
begins, the product will not be sufficiently leavened and will become compact and heavy.
While, double acting baking powder does this twice. It reacts to release carbon dioxide at room
temperature when the dry ingredients are moistened and reacts again when heat is applied during
baking. This double acting baking powder contains two acid substances that each reacts with
soda to release carbon dioxide at different times in the baking process.