The most common ingredients used in baking and their functions are described below:

Flour

 Flour is the main ingredient of baking. Flour means powder that we can get from different cereal grains such as rye, triticale, oat rice and wheat. Wheat flour is commonly used in baking because of its distinctive protein named gluten (8-14%).Gluten a very high-class of protein develops into a thick, cohesive and elastic mass in dough made from flour and water. Gluten gives a light and airy texture to the baked product as it puffs up many times its original volume when placed in oven. Starch granules are embedded in the web of gluten and support the structure.

As strong gluten network is helpful, flour containing high gluten obtained from hard wheat is desirable in bread. Adequate gluten produces an airy texture and good loaf volume in bread. But in cakes, cookies and quick bread little gluten obtained from soft wheat is desirable. The little gluten content makes the product tender and more crumbly texture.

Rice flour, rye flour oat flour, corn flour and soya flour are also used in baking in a little amount where they are required. These flours do not contain gluten. These flours are used as suitable substitute for wheat and for people who do not like gluten. Yeast

Yeast

Yeast consists of many tiny single cell plants. The process of reproduction of yeast is budding. Each bud forms new buds when it breaks away from parent cell. The suitable conditions needed for growth are warmth, moisture and starch plus small amount of sugar. Very low temperature prevents the growth as a result yeast can be stored for limited period of time. To get better result the conditions and the utensils should be kept lukewarm when the yeast is added to the dough. The yeast feeds on starch and sugar and releases CO2, alcohol and sugar. The bubbles of CO2 make the dough puff up. For proper distribution of the CO2 bubbles in the dough, the mixture of water, flour and other ingredients must be kneaded thoroughly. Then the dough is kept sometime in rest to rise again usually to about double its original volume. If the resting time is too long acid produced by the oxidation of the alcohol causes the product to taste sour.

Fat

 Fat performs some major functions in baking. The best action of fat depends on the slip point, the temperature at which the fat just begins to melt. It will be better, if the slip point of the fat is at least 50 above the proving temperature of the dough.

Shortening: Fat shortens the dough by weakening its gluten network. As a result the product becomes more softer, breaking easily and having more tender mouthfeel.

Creaming: when beating and mixing the ingredients fat traps the air producing a batter. This property is helpful for cake baking as the air bubbles expand during baking and produce a light airy texture.

Flavor: Fat retains the pleasant flavor of baked products and prevents the changing of flavor of finished product. The fat should have bland flavor. Fat having bland flavor is commonly used.

Sugar

Sugar is commonly used as a sweetening agent, but it has also major roles in several other processes. Sugar contributes to the series of browning reactions above 160?c and forms brown crust in many baked products. In amino acid-catalyzed caramelisation reactions a sugar aldehyde or ketone is changed into an unsaturated aldehyde or ketone.

In fermented products such as bread, sugar enhance the rate of fermentation .In non fermented products if the amount of sugar is high, it acts as a preservative and improves the keeping quality of the product. The sweetening agents used usually in baking are honey, molasses, applesauce, fruit juice, pure sucrose as castor sugar.

Egg

 In baking egg acts in two conditions i.e. beaten and unbeaten. Beaten egg white acts like a baking powder and gives the dough a light airy texture. This is possible because egg contains a protein named lecithin which helps to hold the air bubbles. In Unbeaten whole eggs lecithin has the action of binder. Moreover Egg acts as emulsifiers, moisteners and nutritionally as a source of fat and all amino acids.

Leavening Agents

The widely used leaving agent in baking is essentially a mixture of sodium bicarbonate (NaHCO3 ) and a week solid acid or acid salt. This mixture is called baking powder. Baking powder produces carbon dioxide for leavening held by fat pockets, gluten and starch. This gas increases the volume of the products and gives the dough a light airy structure. When baking soda is used without acid it makes the product alkaline as it produces a strong base. It also causes health crisis since the NaHCO3 reacts with the HCl in the stomach and produce CO2. Too little amount of baking powder causes the reduction of volume and lightness of the product.

Salt

Salt is added to increase the flavors and sweetness and toughen up the mixture of fat and sugar. The shape and texture of the baked product depend on the amount of added salt because it maintains the yeast fermentation. Lower amount of salt or omitting of salt makes the dough mature quickly.