Читать книгу Food Chemistry. The Role of Additives, Preservatives and Adulteration онлайн

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These types of additives are added to increase the surface area of a dough or batter by creation of gas bubbles inside the dough or batter. They also make the product light in weight. During the baking process, the gas bubbles get expanded so volume of the product increases and a desirable porous structure is obtained. The functions of leavening agents are as follows:

1 1. It makes the final product light and spongy.

2 2. It makes the product digestible.

3 3. It makes it soft.

4 4. It makes the product tastier and appetizing.

The leavening agents used as additives are mainly of two types.

 a. Biological agent: Biological leavening agents are harmless microorganism like yeast Saccharomyces cerevisiae. The yeast cell added ferments the sugar and produces carbon dioxide and ethanol. The yeast added may be active dry yeast or compressed yeast.

 b. Chemical agents: Three types of chemical leavening agents are used. They are baking soda, baking powder, and ammonium bicarbonate. Baking soda contains sodium bicarbonate (NaHCO3) that releases carbon di oxide when heated. Baking soda is always used with acid like buttermilk, vinegar, lemon juice, molasses, honey, vinegar, buttermilk, cocoa fruits, fruit juices, and cream of tartar. Baking powder contains baking soda, dry acids, and starch. Baking powder may be either single acting powder or double acting powder. In single acting baking powder carbon dioxide is released as soon as it is added in the liquid. Double acting baking powder releases carbon dioxide in two stage: first is when it is mixed in cold liquid and second is during baking. Ammonium bicarbonate is another leavening agent that produces carbon dioxide when it decomposes. They are used in the products which are finally dry and porous so that all the ammonia liberated during heating gets released otherwise it will affect the taste.