Biomolecules Lab Report

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Investigation of biochemical composition of nutrients by chemical tests Introduction Biomolecules are carbon element based compounds that vital to living cells. Some main types of biological molecules are carbohydrates, lipids, and proteins. Carbohydrates involve countless monosaccharides and their derivatives, along with macromolecular carbohydrates such as starch, cellulose, glycogen and other extensive group of naturally obtained materials (Khowala, Verma, and Banik 2008, 3). Reece et al.(2012, 40) state that lipids have a specific structure and function than that of other biomolecules which mostly made up of carbon and hydrogen atoms attached by nonpolar covalent bonds. Proteins are polymers consisting of amino acids which perform the…show more content…
Two drops of Sudan Red dye were added to the mixture. 4. The separation of the phases was observed. 5. Two drops of Sudan Red dye were added to 1 ml of high-fat milk. 6. Two drops of Sudan Red dye were added to 1 ml of low fat milk. Experiment 4: Test for protein 1. Equal volumes of KOH and protein solution were carefully added to a test tube and shaken gently. 2. 1 drop of CuSO4 was slowly added letting the drop run down the inside of the test tube. 4. The same Biuret test was conducted using low-fat milk, then high-fat milk instead of protein solution. Experiment 5: Identification of biomolecules in food 1. The provided sugar biscuit was observed and notes of its characteristics were taken. 2. The present biomolecules in the biscuit were identified using the tests performed in the previous four experiments (tests for starch, reducing sugars, lipids, and proteins). Results Experiment 1: Test for starch Table 1: Color change after addition of iodine solution Reactions Color change Starch solution and iodine solution From yellow brown to dark purple Potato and iodine solution Dark purple Figure 1: Drawing of stained potato sample under a microscope Experiment 2: Test for reducing sugars – mono and…show more content…
Thus, the oil phase appeared at the top as it has lower density than water (Reeds et al. 2012, 40). Sudan Red Dye colors only non- polar substances, therefore, hydrophobic lipids were stained to red color. Holmbarg and Thelin (2013) illustrate that whole fat milk has fewer hydrocarbons than low-fat milk and that it mainly constitutes of fats, as a result, it was stained to saturated pink color. Experiment 4: Test for protein Keppy and Allen (2009, 1) explain the color change in Table 4 as “the result of the complexity of Cu2+ to functional groups in the protein’s peptide bonds.” The two peptide bonds are necessary for the production of a purple- colored chelate product which is formed by the compound Cu2+-protein (Keppy and Allen 2009, 1). As it was discussed before, in low-fat milk fats are replaced by carbohydrates and proteins, accordingly, it forms darker color of purple than the milk with higher concentration of fats (Holmberg and Thelin. 2013). Experiment 5: Identification of biomolecules in
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