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The macromolecule laboratory aimed to identify the presence of macromolecules in various food samples and distinguish between positive and negative tests. This report documents the experimental procedure, results, and conclusions drawn from the tests conducted on an unidentified food sample (Cheddar and Sour Cream chips). Four macromolecules - sugar, starch, protein, and lipids - were examined using specific reagents. The results indicated the presence of starch, fat, and protein in the food sample.
In this laboratory experiment, the objective was to determine the presence of macromolecules in food samples and differentiate between positive and negative test reactions.
To achieve this, each participant brought in an unidentified food sample, and known macromolecule substances were used as references for comparison. The four macromolecules examined were sugar, starch, protein, and lipids. The hypothesis stated that a color change in the test samples would indicate a positive reaction, and this reaction would be compared to the color change observed in the reference samples.
1. Eight test tubes were prepared, each containing half distilled water and half of the respective macromolecule substance.
2. For the sugar test, 10 drops of Benedict's solution were added to the test tube containing water and glucose, and both tubes were placed in boiling water for 3 minutes.
Color changes were observed and noted.
3. For the starch test, 10 drops of iodine reagent were added to the starch-containing test tube and to the test tube containing distilled water.
After swirling the tubes, color changes were observed and recorded.
4. The protein and fat tests followed a similar procedure as the starch test, but with Biuret reagent for protein and Sudan red reagent for fat.
| Substance | Test | Color Change |
|---|---|---|
| Cheddar and Sour Cream Chips | Sugar solution | Purple (top), Dark Blue (bottom) |
| Starch | Black | |
| Protein | Violet | |
| Lipid | Bright Red |
In the macromolecule lab, the independent variables were the distilled water and the macromolecule samples to which reagents were added. The dependent variables that remained constant throughout the experiment included pipettes, test tubes, mortar and pestle, lab report sheet, and test tube rack. The positive tests with known reactions served as controls to compare the reactions in the food sample.
The results of the tests conducted on the Cheddar and Sour Cream chips revealed that the food sample contained starch, protein, and lipids. The presence of starch can be attributed to the potatoes used in making the chips, while the protein and lipid content may be due to other ingredients used in the manufacturing process.
For the sugar test, the color change in the chips' solution indicated a positive reaction. The chips likely contained sugar, as suggested by the color change to purple and dark blue.
In the starch test, the chips' solution turned black, indicating a positive reaction for starch. This result aligns with the expectation that potato-based chips would contain starch.
The positive reaction to the Biuret reagent, turning violet, confirmed the presence of proteins in the chips. This finding suggests that the chips contain protein-rich ingredients, possibly from sources like cheese or other dairy products.
Finally, the bright red color change in response to the Sudan red reagent indicated the presence of lipids (fats) in the chips. The fats in the chips are likely derived from the cooking process and any added oils or fats in the seasoning.
The Cheddar and Sour Cream chips tested positive for starch, protein, and lipids. These findings align with the ingredients commonly used in potato chips. The presence of macromolecules in the chips was confirmed by comparing the color changes to the positive reactions observed in the reference samples. The experiment successfully identified the macromolecules present in the unidentified food sample.
Further experiments can be conducted to quantify the exact amounts of each macromolecule in the Cheddar and Sour Cream chips, providing more detailed nutritional information. Additionally, this lab procedure can be used to analyze other food products for their macromolecule content, contributing to a better understanding of food composition and nutrition.
Macromolecules in Food Samples: Laboratory Report. (2016, May 13). Retrieved from https://studymoose.com/document/macromolecules-lab-bio-1-lab
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