Testing for Starch in Food

FOOD and NUTRIENTS

The earth provides us with many resources including food and fiber. Much of the food we eat comes from plants. Crops are plants that are grown specifically to be food which include grains, fruits, and vegetables.

Vitamins, minerals, carbohydrates, protein, and fat are nutrients that come from food and our bodies use to function.

Carbohydrates are the most common source of energy for the body. It is mainly provided through plant foods and includes sugars and starches. Starches are chemically bound clusters of sugar molecules found in plants. Your body breaks down starch molecules into sugar.

Testing for Starch

There is a simple test to determine if a food contains the nutrient, starch. Iodine can be used as an indicator of starch in food, because in the presence of starch, iodine makes a chemical reaction to turn the sample to a dark blue or purple black color. If there is no starch present, the iodine remains the original brownish yellow color.

Supplies

Paper Towel, paper or plastic plate or protective surface

Iodine* (Be careful it can stain skin and clothes)

*Check your first aid kit or the local pharmacy for iodine.

Different kinds of food for testing such as:

Cut potatoes or potato chips or hash browns

Cut fruit like an orange or apple slice

Bread

Crackers

Cheese (I used parmesan because it is light colored)

Corn or popcorn

(You can use whatever you have on hand. Just choose a variety of foods from different food groups)

Step 1: Gather Your Supplies, and Place the Foods on the Protective Surface.

Step 2: Try to Predict Based on Your Knowledge of Nutrition If a Food Has Starch. Then, Place 1 Drop of Iodine Onto Each Food.

Step 3: The Foods Containing Starch Will Turn Purple/black Where the Iodine Touches Them. If the Color Is Brownish Yellow, Then There Is No or Just a Little Starch.

Step 4: If You Are Having Trouble Determining the Color, You Can Put the Food Sample in a Little Water First. Then Add the Iodine.

Step 5: Explanation

Starch contains two types of polysaccharides that are made up of glucose units, or long chain of simple sugars that make it a complex sugar. One of the chains of sugars is amylose. When the amylose meets the iodine there is a reaction that causes a blue color change.

Step 6: Vocabulary

Chemical reaction is the combination of two materials that produces a new substance or product.

Carbohydrates are the most common source of energy for the body. It is mainly provided through plant foods and includes sugars and starches.

Sugar is an essential structural part of living cells. It is a source of energy and a natural part of many foods. Fruit is a good source of natural sugar.

Starch is a chemically bound cluster of sugar molecules found in plants. Your body breaks down starch molecules into sugar. A potato is an example of starch.

Vitamins and minerals are essential to the body because they build body tissue and help other nutrients do their jobs. The body cannot produce energy without them. Oranges contain vitamin C which is good for the immune system and wound healing. Milk is a good source of the mineral calcium which is important to bone health.

Protein is important for growth and repair. Muscle, hair, skin, and connective tissue are mainly made up of protein. Protein plays a major role in all of the cells and most of the fluids in our bodies. Meat and beans are a source of protein.

Fat is also a nutrient that the body needs for energy storage and for vitamin and mineral absorption. There are both animal and plant fats. Avocados and nuts are sources of plant fat. Butter and meat are examples of animal fat.

For more information:

https://www.choosemyplate.gov/

https://www.biologyonline.com/dictionary/starch