The Browning of An Apple Under Various Circumstances PDF

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The Browning of An Apple Under Various Circumstances

Introduction Fresh fruits; although delicious can begin to rot almost instantly after being cut. This is because of the enzyme oxidation in fruits – specifically apples for the purpose of this lab. The rotting is visible on fruits in forms such as browning. When an apple brown, oxygen has been introduced to the fruit and polyphenol oxidase (PPO) oxidize the phenolic compounds which are found in apple tissues (Espley et al., 2019). The objective of this experiment is to determine which environment is ideal for apples to stay fresh, including differences in temperatures, pH and oxygen levels. The different environments include room temperature (about 22°C), 4°C, room temperature in water and room temperature covered in lemon juice. The browning process will be accelerated when exposed to oxygen due to the oxidation enzymes and left in cool areas. The process will be reduced when left in warm conditions due to the denaturing of the enzyme and acidity will activate the PPO thus also accelerating the process (Murtaza et al., 2020). Materials and Method All procedures were carried out as outlined in Experiment Name, BIOL 130L lab manual. (Department of Biology, 2020). No deviations were made to these protocols.” Results Each of the four slices was placed in its given condition. Change was noticed in 15-minute intervals and after 3 hours. The change browning is described on a scale of 0-5. * Figure 1: Apple Browning Results on a Scale Time 30 Time 45 Time 3 Minutes Time 0 Minutes Time 15 Minutes Minutes Minutes Cold Temperature Room Temperature Room Temperature Immersed in water Room Temperature covered in Lemon Juice

* A browning scale of 0-6 is used. 0 being the apple slice is not brown at all and 6 being the apple slice is extremely brown. * Discussion The browning of an apple lab showed the effects of different environments on the enzymatic behaviour of a fruit. It was predicted that the warm temperature (room temperature) would denature the enzyme thus not allowing it to speed up the process, however that was not the case. The temperature was not warm enough to preform like a denatured enzyme. The denaturing temperature of enzymes varies from about 40C to 120C (Daniel, Dines, & Petach, 1996). The

theory that immersion in water would oxidize the apple was also disproven as the apple was only a level 3 brown after 3 hours. However, the theory that an acidic substance will slow down the browning of an apple was proven correct. The addition of citric acid lowered the pH and prevented the enzymatic activity. Keeping the apple in a cool location also was proven to accelerate the browning process, due to the exposure of oxygen. Somethings that could’ve affected the results of the browning process were the room temperature and the apple used. Suppose the apples were kept in a room at room temperature, it is possible the temperature in the room fluctuates. Also, the results could vary based on which type of apple is used and the environment the apple was grown in. Different apples could be used to different environments thus affecting the way they behave under the lab circumstances. Overall, the activity of the PPO enzymes allowed us to see how different environments react and create unique enzymatic behaviours.

Works Cited Daniel, R. M., Dines, M., & Petach, H. H. (1996). The denaturation and degradation of stable enzymes at high temperatures. The Biochemical Journal, 317 ( Pt 1)(Pt 1), 1–11.

Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1217448/ Department of Biology. (2020) Introductory cell biology laboratory. Waterloo, Canada : Univeristy of Waterloo Print + Retail Solutions. Espley, R. V., Leif, D., Plunkett, B., McGhie, T., Henry-Kirk, R., Hall, M., … Allan, A. C. (2019). Red to Brown: An Elevated Anthocyanic Response in Apple Drives Ethylene to Advance Maturity and Fruit Flesh Browning. Frontiers in Plant Science, 10. https://doi.org/10.3389/fpls.2019.01248 Murtaza, A., Iqbal, A., Marszałek, K., Iqbal, M. A., Waseem Ali, S., Xu, X., … Hu, W. (2020). Enzymatic, Phyto-, and Physicochemical Evaluation of Apple Juice under High-Pressure Carbon Dioxide and Thermal Processing. Foods, 9(2). https://doi.org/10.3390/foods9020243...