Laboratory 1 – Food Testing Welcome, Students! Laboratory 1 – Food Testing

Laboratory 1 – Food Testing Purpose: To determine whether three food samples are made of carbohydrates, proteins, or fats (lipids). Materials: 3 Unknown Samples Benedict’s Solution Hot Plate Biuret’s Solution 500 mL beaker Q-tips 6 test tube Pieces of White Paper Water

Food Test 1: Sugar test-Benedict's solution 1. Add 40 drops of Unknowns 1, 2, and 3 to test tubes labeled 1, 2, and 3, respectively. 2. Add 10 drops of Benedict's solution to each test tube. Heat the test tubes the hot water bath for five minutes. 3. Note any color change. If sugar is present solution will turn green, yellow, or brick-red, depending on sugar concentration.

Food Test 2: Protein – Biuret's Reagent 1. Add 40 drops of Unknowns 1, 2, and 3 to test tubes labeled 1, 2, and 3, respectively. 3. Add 3 drops of Biuret’s reagent solution to each test tube. Shake gently to mix. 4. Note any color change. Proteins will turn solution pink or purple.

Food Test 3: Lipids (Fat) – Smear Test 1. Use a Q-tip to smear a small amount of Unknowns 1, 2, and 3 on a piece of white paper. Labe the smears 1, 2, and 3 respectively. 2. Place on the hot plate and allow to dry. 3. If the smear remains translucent (clear) then Lipids (Fats) are present. 4. Dispose of all liquids in the waste beaker. Dispose of the Q-tips and piece of paper in the trash.

Data Table Unknown 1 2 3 Carbohydrates - Benedict’s Solution Proteins – Biuret’s Solution Lipids (Fats) - Smear Test