The five food items tested for the presence of carbohydrates (sugars and starch), lipids, and proteins were coconut milk, karo syrup, potato chips, peanut butter, and banana baby food.
We predicted that coconut milk would have carbohydrates, fats, proteins, and starches while karo syrup would only simple sugars. Additionally, we guessed that potato chips contained fat and starch while peanut butter had sugar, fat, and protein. Lastly, we hypothesized that banana baby food consisted of sugar and starch.
To test for the presence of carbohydrates, we used the Benedict’s test. This test is performed by adding Benedict’s solution, a copper sulfate based solution, to the food sample. If the solution turns green, there are simple carbohydrates present in the food. If the solution turns yellow, there are complex carbohydrates (starch) in the food. No change in color indicates that there are no carbohydrates present.
To test for lipids, we used the paper towel test. A piece of paper towel is placed on top of the food sample and then pressed down with a glass plate. After a few minutes, the paper towel is removed and examined. If there is an oily sheen on the paper towel, then lipids are present in the food. If there is no sign of an oily sheen, then there are no lipids present.
To test for proteins, we used the Biuret’s test. This test is performed by adding a few drops of Biuret’s solution, a copper sulfate based solution, to the food sample. If the solution turns pink or purple, then proteins are present in the food. If the solution remains blue, then there are no proteins present.
The results of our tests showed that coconut milk contains all four types of macromolecules, karo syrup only contains simple sugars, potato chips contain starch and fats, peanut butter contains sugars, fats, and proteins, and banana baby food consists of sugars and starch.
To test for the presence of macromolecules, we diluted five samples of each food item and added Benedict’s reagent to show the presence of sugar, IK2I for starch, and Buiret’s reagent for protein. To test for lipid existence, we used a simple paper method. Our results were in line with our estimations.
The testing results verified that coconut milk contained all four types of macromolecules, karo syrup contain only simple sugars, potato chips were starches and fats, peanut butter contained sugars, fats, and proteins, and banana baby food consisted of sugars and starches.
Benedict’s reagent turned yellow in the karo syrup and orange in the banana baby food, signifying the presence of simple sugars. IKI2 test for starch showed a dark purple color with the potato chips, but no color change with any of the other foods. The paper towel test for lipids was positive with peanut butter and potato chips. Lastly, Buiret’s reagent turned blue-green with peanut butter, showing evidence for protein.
When we identify the macromolecules in our food, we can better understand how to create a healthy diet that provides essential nutrients for cellular processes in the human body. The three main categories of macromolecules are carbohydrates, lipids, and proteins. Carbohydrates include sugars and starches, while lipids refer to fats.
Proteins are nitrogen-containing polypeptides that exhibit a vast range of functions. All macromolecules are essential for human nutrition, but the type and amount of each macromolecule differ in the foods we eat.
We tested five different food items – coconut milk, karo syrup, potato chips, peanut butter and banana baby food – for the presence of specific macromolecules. These were identified as sugars, starch, lipids and proteins. We used chemical indicators and brown paper to detect the various macromolecules in each solution made from a sample of each food item.
All five food items tested positive for sugars, lipids, and proteins. However, only the karo syrup and potato chips contained starch.
This experiment was designed to test for the presence of four common macromolecules in various food items: sugars, starch, lipids, and proteins. Food items were chosen that are commonly consumed and are known to contain all four macromolecules. For testing, we used chemical indicators and brown paper to detect the presence of each macromolecule in a given sample. All five food items tested positive for the three macromolecules: sugars, lipids, and proteins.
With Benedict’s reagent, if sugars are present in a food then the solution will turn orange and precipitate will form. If starch is present, iodine potassium iodide will turn the solution dark purple or brown and form a precipitate. When performing lipid tests with Brown paper, if lipids are present in the food then it will rub off onto the paper forming a transparent area.
Lastly, if protein was present in a food, then the Biuret’s reagent would turn the solution violet and form a precipitate.
Different foods will have different macromolecules present in them. For example, table sugar (sucrose) is composed of only sugar molecules, while complex carbohydrates like starch can be found in foods like bread and potatoes. Fats and oils are examples of lipids, and can be found in meats, dairy products, and some plant-based foods. Proteins are common in animal products like meat and eggs, but can also be found in beans and other plant-based foods.
To test for the presence of macromolecules in common foods, we can use a few simple chemical tests. The Benedict’s test is used to test for the presence of sugars, and uses Benedict’s reagent, which is a solution of copper sulfate. If sugars are present, the reagent will turn orange and precipitate will form. The iodine potassium iodide test is used to test for the presence of starch, and uses iodine as the indicator.
If starch is present, the solution will turn dark purple or brown and form a precipitate. The lipid test is used to test for the presence of fats and oils, and uses brown paper as the indicator. If lipids are present, the paper will form a transparent area. Lastly, the Biuret’s test is used to test for the presence of protein, and uses Biuret’s reagent, which is a solution of copper sulfate. If protein is present, the solution will turn violet and form a precipitate.