Callaghan 1 Timothy (Scott) Callaghan Dr. Kemp/Ms. Tale BIOL 111-553 Biomolecules Lab Report The presence of lipids in food has always been a concern for people worldwide, as present lipids almost definitely mean the presence of fats, as fats are a subgroup of lipids called triglycerides. This is important to anyone maintaining or attempting to achieve a certain weight, as almost all people seeking weight loss avoid fats, therefore, avoiding foods in which lipids appear to be present. My hypothesis is: if a food has been processed, it will test positive for lipids in the lipid emulsion test. I thought this because, in my experience of dieting, I’ve personally found that processed foods tend to be fattier than unprocessed or natural foods. Because of this appearance of fats in processed foods, I make the educated guess that lipids will appear more in processed foods than natural foods. On the other hand, my null hypothesis is: if a food has been processed, it will test negative for lipids in the lipid emulsion test. Before starting the experiment, there is already set positive and negative control groups, with positive being butter and representing a presence of lipids, and negative being water and representing no presence of lipids. The experiment involves using test tubes, a hot plate, a glass beaker, distilled water, ethanol, Sudan IV, along with a potato peel, bread, and salad dressing as the reactants. For all three reactants, I put each respective reactant into its own test tube, with each test tube containing 4 milliliters of ethanol. Then, I covered the top of each tube with Parafilm and slowly shook each solution for about a minute. Next, each solution is supposed to show either a cloudy or clear appearance, with cloudy representing the presence of lipids, and clear representing no presence of lipids. After observing each test tube solution, I added 20 drops of Sudan IV solution to each and waited for five minutes to observe whether red droplets would appear around the top of the test tube. If red droplets form at the top, Sudan IV indicates that lipids are present in the solution, but if the Sudan IV mixes evenly with the test tube solutions, then lipids are not present. For the potato peel, I predicted that lipids would be not present because of its high starch content, and starch is a carbohydrate. This turned out to be correct, as the ethanol-potato peel solution was not cloudy, nor did red droplets from the Sudan IV solution appear either, resulting in a negative control. Similar to the potato peel, I also predicted that bread would have no lipids, because of bread’s high concentration of carbohydrates. Even though bread is a processed food, it is not processed enough to the point of having lipids, simply because bread is mainly carbohydrates. This was also correct, as the ethanol-bread solution resulted in no clouds, and no red droplets formed when the Sudan IV solution was added, resulting in a negative control. Lastly, I predicted that the salad dressing would have present lipids, as salad dressing is a highly processed food with fat in it. This was also correct, with the ethanol-salad dressing solution forming clouds, and then forming red droplets at the top of the test tube when Sudan IV was added, resulting in a positive control. With these results, I now accept my hypothesis over myCallaghan 2 null hypothesis, as processed foods resulted in a presence of lipids. The only exception to this is bread, as the wheat bread I used was slightly processed, but I expected the bread to test negative for lipids, as bread is mainly carbohydrates. This experiment is important because, through these tests, people looking to lose weight can now see which foods contain lipids and which do not, as lipids correlate with the food’s fat content. Table 3-3 Control Substance Prediction Ethanol Result Sudan IV Result Positive Butter Lipids Cloudy Red Droplets Negative Water No Lipids No Clouds No Red Droplets Negative Potato Peel No Lipids No Clouds No Red Droplets Negative Bread No Lipids No Clouds No Red Droplets Positive Salad Dressing Lipids Cloudy Red DropletsCallaghan 3 Works Cited Harris-Haller, Tonna. Biology 111 Laboratory Manual. Hayden-McNeil Publishing,
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