Starch is a type of carbohydrate that is available in large quantities in nature , occurring in greater quantities than cellulose. It is a carbohydrate of vegetable origin that is found mainly in reserve organs, cereal grains and roots. Among the main starchy foods, we can mention potatoes, sweet potatoes, wheat, cassava, corn, oats and rice.
Starch is formed by alpha-D-glucose chains that can be linear ( amylose ) or branched ( amylopectin ). All starches are formed by one of these molecules or an association between them. Corn, for example, has approximately 25% amylose and 75% amylopectin. Waxy rice does not have amylose.
This important carbohydrate is found in vegetables in granules of different sizes and shapes. Each granule can have amylose, amylopectin or a heterogeneous mixture of these macromolecules. In plants, starch acts as an energy source, being used normally during dormancy periods and during germination. This substance is considered the main reserve substance in higher plants.
Starch is not only important for the vegetable, but also for other organisms as a form of energy. It is estimated that 80% of the calories consumed by man come from this carbohydrate.
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In the industry, starch is used in the manufacture of different types of food, such as sauces, dairy drinks, soups and flours. In addition to food, starch is used in the pharmaceutical, textile, metallurgical and even civil construction industries.
To generate better results in its use, starch is usually modified in the industry, undergoing chemical, physical and thermal processes. The modification of starch guarantees, for example, an increase in its solubility, emulsifying action, resistance to cooking and change in viscosity.
→ Checking for starch in food
To check whether a food has starch in its composition or not, a simple and quick experiment can be performed. Just drop a drop of diluted iodine tincture (five drops of tincture into a cup of water coffee) over the food and wait for the reaction.
Iodine has the ability to bind starch and form a complex. This interaction is visible due to the formation of a blue colored compound. Therefore, if the food turns blue, it contains starch.