How to Test for Protein in Food
Tests & Procedures

How To Test For Presence of Protein in Food?

Protein is a major building block in our bodies. It is one of the 3 major critical nutrients found in food, alongside carbohydrates and vitamins food groups. Protein is essential in the building of muscle. The presence of protein in a food is tested in a laboratory setting using the Biuret Test. This article looks at how to test for protein in food.

Healthy living requires you to know how well your diet is. It makes it important to know how to test for protein in food so you can balance your diet better. Your diet should take into account your age, existing medical conditions and how active your lifestyle is. A dietician is useful in helping you settle on the diet you will follow.

Uses of Protein in Food

Protein is needed in your body at a rate of 4 to 5 ounces portions per day. Too much protein leads to the toxicity of the kidneys and liver. There is also the production of excess proteinaceous toxins in your colon. You will know these toxins are present by a foul smell in your stool. You should have enough protein in your diet. Deficiency of protein leads to variation in body weight. It can cause severe malnutrition if left unchecked.

The purpose of the test for the presence of protein in food is because proteins are useful in many areas of the body. The main body processes that require proteins are the production of hormones, movement and locomotion, production of enzymes and to be used as fuel when necessary. Other uses of protein in food are

  • Transport of oxygen and nutrients
  • Repairing old and worn out cells
  • Storing and holding genetic information
  • Structural integrity

It is not ideal to use proteins as fuel in your body. The body prefers carbohydrates as fuel. Balance your diet to include all food groups.

[Read – Adverse Effects of Excess Protein in Body]

How To Test For Protein in Food

Testing for protein in food is simple. You can do it at home or school using the readily available equipment. The popular test for protein in food is the Biuret Test. You will need the food to be tested, an eyedropper, biurets reagent, a test tube or some small container to carry out the biuret test for protein in food.

It is important to protect your skin from biuret reagent. It can stain you and other surfaces. A metal sink or the outdoor is the best place to carry out the biuret test. It is recommendable that you wear rubber gloves while carrying out the test procedure.


The simple procedure to know the protein in food at your home is

  • Create a paste or liquid from the food you are testing for protein.
  • You will add reagent to this paste or liquid. The paste should be of an adequate amount. It should also be easy to mix with reagents.
  • Add 40 drops of your mixture to a small container.
  • Add 3 drops of biuret reagent to your mixture and shake well.

Protein in Food Test Results

Look out for changes of color. If there is protein in the food, the solution will turn pink or purple. The simple biuret test does not show how much protein is in a food.

There are different types of protein foods and each has varying quality as sources of protein. The best foods for good protein levels in your body are dairy foods. These include yoghurt, milk and cheese. Go for low fat dairy products to keep away osteoporosis. Other foods high in protein content are fish, chicken, beans, lentils, nuts and eggs.

Plant protein differs from animal protein in quality. Animal products give more protein per weight. Eggs have the highest protein levels. Plant proteins are as important as animal proteins. They contain proteins that are not found in animal products. Make sure to have a good mix of both animal and plant proteins in your diet. Additionally, take a few minutes to test a few foods since you now know how to test for protein in food.

Medically Reviewed By
Dr. Kaushal M. Bhavsar (MBBS, MD)Assistant Professor in Pulmonary Medicine, GMERS Medical College, Ahmedabad