As every GCSE student can tell you, photosynthesis is the process through which light energy is converted into either chemical energy or sugar. Plants make, and store temporary supplies of starch in their leaves, which they use during the night when there is no light available for photosynthesis.

During the process of photosynthesis, cells use carbon dioxide and energy from the Sun to make sugar molecules and oxygen. These sugar molecules are the basis for more complex molecules made by the photosynthetic cell, such as glucose.

Plants produce starch by first converting glucose 1-phosphate to ADP-glucose using the enzyme glucose-1-phosphate adenylyltransferase. The enzyme starch synthase then adds the ADP-glucose via a 1,4-alpha glycosidic bond to a growing chain of glucose residues, liberating ADP and creating amylose.

Starch is synthesized in the plastids—chloroplasts in leaves or specialized amyloplasts in the starch-storing tissues of staple crops.

Starch is a long-chain polymer of glucose molecules joined together. As the plant adds one glucose molecule to the starch polymer, one molecule of water is released. Plants create starch polymers, for example in grains of wheat, to store the glucose made by photosynthesis.

The process by which glucose is converted to starch is known as “dehydration synthesis.” A water molecule is released as each of the simple sugar molecules of glucose are added to the starch molecule, according to Biology Online.

Starch is amongst the most abundant plant products and is a mixture of two polymers, amylose and amylopectin. During food processing starch is transformed by hydrothermal treatments. The structure of starch is also influenced by specific and non-specific interactions with other food constituents and ingredients.

Iodine solution is used to test leaves for the presence of starch. You need to: heat a plant leaf in boiling water for 30 seconds (this stops its chemical reactions) heat it in boiling ethanol for a few minutes (this removes most of its colour)

This plant starch test looks for evidence of photosynthesis Photosynthesis is the process in which green plants (primarily) convert energy from the sun’s light into usable, chemical energy. The presence of starch in a leaf is reliable evidence of photosynthesis. That’s because starch formation requires photosynthesis.

Biuret reagent

Take a piece of the food item. Add 2-3 drops of dilute iodine solution on it. If the colour of the food item becomes blue-black, then it indicates the presence of starch in that food and if the colour doesn’t turn into blue-black, then it indicates starch is not present.

Starch Test: Add Iodine-KI reagent to a solution or directly on a potato or other materials such as bread, crackers, or flour. A blue-black color results if starch is present. If starch amylose is not present, then the color will stay orange or yellow.

iodine solution

Starch is a carbohydrate naturally found in many grains and vegetables, such as wheat, maize and potatoes, rice, peas, pulses, manioc, sweet potatoes, and bananas etc.

chloroplasts

Water Content of Vegetable For example, vegetables such as celery, cucumber, iceberg lettuce, tomato and zucchini contain over ninety percent water. Other nutrient-rich vegetables with high water content include broccoli, green cabbage, cauliflower, eggplant and spinach.

Examples of starchy vegetables include: Beetroot. Cassava. Parsnips.

The non-starchy vegetables category is much larger and includes veggies like spinach, celery, broccoli, radishes, onions, garlic, tomatoes, cucumbers, carrots and beets. Non-starchy vegetables deliver a powerful punch of vitamins, minerals and phytonutrients.

Non-starchy vegetables include spinach, carrots, lettuce, greens, cabbage, bok choy, green beans, broccoli, cauliflower, tomatoes, vegetable juice, salsa, onion, cucumber, beets, okra, mushrooms, peppers, and turnip.