The Enzymatic Browning of Apples
The purpose of the experiment is to measure the level of browning, due to the effects of the enzyme called polyphenol oxidase (phenolase), on apple slices exposed to different Ph. levels.
When exposed to oxygen the enzyme catalyzes the reaction creating melanins (brown pigments) on the fruit. Soaking the apple slices in acetic acid, orange juice (ascorbic acid), tap water and calcium carbonate (alkaline) will affect the rate in which the apple slices brown. The reduction of the browning is dependent on the Ph. levels of the soaking solutions, also soaking the apple slice in water will restrict the amount of oxygen that comes into contact with the apple thus temporarily inhibiting the effects of the phenolase.
Understanding the Prac:
By peeling or cutting fruit and vegetables the enzymes that are stored within the plant cells are released. When in the presence of oxygen the enzyme phenolase catalyzes the biochemical reaction of converting phenolic compounds into melanins. Enzymatic browning occurs optimally between a PH of 5.0 and 7.0.
Browning can also occur via the bruising or other injury to the plant tissue, exposing the enzyme to oxygen. Although enzymatic browning is not always a defect, for instance it is required in the process of making raisins, coffee, prunes and cocoa, it does however have significant effects on the fruits and vegetables that do not require browning such as apples. Enzymatic browning not only
In the experiment we used Turnip, Hydrogen Peroxide, Distilled Water, and Guaiacol as my substances. On the first activity, Effect of Enzyme concentration of Reaction Rate for low enzyme concentration, we tested three concentrations of the turnip extract, and hydrogen peroxide. For the Turnip Extract I used 0.5 ml, 1.0 ml, and 2.0 ml. For hydrogen peroxide we used 0.1 ml, 0.2 ml, and 0.4 ml. We used a control to see the standard, and used a control for each enzyme concentration used. The control contains turnip extract and the color reagent, Guaiacol. We prepared my substrate tubes separately from the enzyme tubes. My substrate tube
The use of multiple test tubes and Parafilm was used for each experiment. Catechol, potato juice, pH 7 phosphate buffer, and stock potato extract 1:1 will be used to conduct the following experiments: temperature effect on enzyme activity, the effect of pH on enzyme action, the effect of enzyme concentration, and the effect of substrate concentration on enzyme activity. For the temperature effect on enzyme activity, three test tube were filled with three ml of pH 7 phosphate buffer and each test tube was labels 1.5 degrees Celsius, 20 °C, and 60 °C. The first test tube was placed in an ice-water bath, the second test tube was left at room temperature, and the third test tube was placed in approximately 60°C of warm water. After filling the test tubes with three ml of the
The role of an enzyme is to catalyse reactions within a cell. The enzyme present in a potato (Solanum Tuberosum) is catechol oxidase. In this experiment, the enzyme activity was tested under different temperature and pH conditions. The objective of this experiment was to determine the ideal conditions under which catechol oxidase catalyses reactions. In order to do this, catechol was catalyzed by catechol oxidase into benzoquinone at diverse temperatures and pH values. The enzyme was exposed to its new environment for 5 minutes before the absorbance of the catechol oxidase was measured at 420 nm using a spectrophotometer. The use of a spectrophotometer was crucial for the collection of data in this experiment. When exposed to hot and cold temperatures, some enzymes were found to denature causing the activity to decrease. Similarly, when the pH was too high or low, then the catechol oxidase enzyme experienced a significant decrease in activity. It can be concluded after completing this experiment that the optimal pH for catechol oxidase is 7 and that the prime temperature is 20º C. Due to the fact that the catechol oxidase was only tested under several different temperatures and pH values, it is always possible to get a more precise result by decreasing the increments between the test values. However, our experiment was able to produce accurate results as to the
Introduction: Starting out with some background information, I know that enzymes are biological catalysts. The enzyme that I used for this experiment was potato juice. Enzymes make reaction rates go faster. They lower activation energy, making chemical reactions. Temperature has an effect on canola cultivars. The higher temperature decreased stem diameter, but room temperature had thicker stems. So I believe the same will happen for the catechol oxidase; the solution will react faster at room temperature. Other enzymes can also have different effects such as the enzyme in cattle serum. The enzyme lost activity in room temperature. With that being said room temperature can also be detrimental with specific enzymes. Fungus also
The cell membrane (Plasma membrane) functions to provide cell support, cell stability and control entry and exit of materials from the cell. This study was conducted to test the effects of environmental conditions such as the on beet root cell membrane (Beta vulgaris). Five trials using varied pH concentrations were tested and absorbance rates were monitored. The experimental results showed that the protein function decreased sequentially when the pH decreased. This allowed the betacyanin dye to leak out which created the color that was needed to determine the intensity and therefore the effect of the circumstances. This supported the hypothesis that the more acidic or basic the environmental condition around the beet cell, the more permeable the, membrane indicated by color intensity. Pigment leakage in the solution was analyzed by using a spectrophotometer.
These results shown from this experiment led us to conclude that enzymes work best at certain pH rates. For this particular enzyme, pH 7 worked best. When compared to high levels of pH, the lower levels worked better. The wrong level of pH can denature enzymes; therefore finding the right level is essential. The independent variable was the amount of pH, and the dependent being the rate of oxygen. The results are reliable as they are reinforced by the fact that enzymes typically work best at neutral pH
This is because each kind of apple has a different concentration of catechol oxidase (Daniela Finkel, 2013). Therefore, each apple has a unique speed at which it will produce benzoquinone, and turn brown.
Peroxidase is an enzyme found in potatoes that catalyzes the breakdown of hydrogen peroxide, H2O2, into O2 gas and water. We examined the different pH environments that can affect the enzyme activity during the breakdown of H2O2. In order to do this, we added different levels of pH, low, medium, and high, into different test tubes with the enzyme and H2O2, and we then inverted the tube. The amount of O2 gas produced was then measured and recorded. The result was that the higher pH produced more gas, followed by medium pH, then low pH. The enzymes were more active in the pH of about 10. It increased
The aim of my investigation is to see how pH affects the activity of potato tissue catalase, during the decomposition of hydrogen peroxide to produce water and oxygen.
Catechol, in the presence of oxygen is oxidized by catechol oxidase to form benzoquinone (Harel et al., 1964). Bananas and potatoes contain catechol oxidase that acts on catechol which is initially colorless and converts it to brown (Harel et al., 1964). In this experiment, the effect of pH on the activity of catechol oxidase was conducted using buffers ranging from pH2 to pH10. Two trials were conducted due to the first trial results being altered by an external factor. The results were acquired by taking readings every 2 minutes for 20 minutes from a spectrophotometer and then recorded on to the table. The data collected in the table were then made into graphs to illustrate the influence of pH on the catechol oxidase catalyzed reaction. After analysis, the data revealed that pH did have a significant influence on the enzyme as recorded by absorbance per minute. However, the data was collected was not accurate due to external factors, thus the results are debatable and should be experimented again for validation.
During these experimental procedures, the implication of multiple different temperatures on fungal and bacterial amylase was studied. In order to conduct this experiment, there were four different temperatures used. The four temperatures used were the following: 0 degrees Celsius, 25 degrees Celsius, 55 degrees Celsius, and 80 degrees Celsius - Each temperature for one fungal and one bacterial amylase. Drops of iodine were then placed in order to measure the effectiveness of the enzyme. This method is produced as the starch test. The enzyme was tested over the course of ten minutes to determine if starch hydrolysis stemmed. An effective enzyme would indicate a color variation between blue/black to a more yellowish color towards the end of the time intervals, whereas a not so effective enzyme would produce little to no change in color variation. According to the experiment, both the fungal amylase and bacterial amylase exhibited a optimal temperature. This was discovered by observing during which temperature and time period produced a yellow-like color the quickest. Amylase shared a similar optimal temperature of 55 degrees Celsius. Most of the amylases underwent changes at different points, but some enzymes displayed no effectiveness at all. Both amylases displayed this inactivity at 0 degrees Celsius. At 80 Celsius both the enzymes became denatured due to the high temperatures. In culmination, both fungal and bacterial amylase presented a array of change during it’s
Turnips and horse radish roots are rich source of this enzyme. In this experiment, we would carry out a reaction between hydrogen peroxide and guaiacol which is colorless dye, using peroxidase as a catalyst, to produce water and an oxidized form of guaiacol which is brown. The formation of brown color would serve as an indicator that the breakdown of Hydrogen Peroxide took place. The enzyme activity would be directly proportional to the brown color intensity. The color intensity would be measured using a spectrophotometer and standardized to find the corresponding concentration for each absorbance unit.
will give me an idea on what I should change or keep the same. It will
Based on the class data of the pH of phosphorylase reaction, the potato phosphorylase is reached the endpoint which the phosphorylase active at pH 6, it started active within 6 minutes. The optimal pH of phosphorylase is at pH 7 which active just within 4 minutes. At pH 6, it started to breaking down the starch primer +glucose-1-phosphase into starch + phosphate which reacted with the iodine test to formed the blue precipitate. At the optimal pH 7, it shows that it maximized its activity. Comparing the data of the pH of the potato phosphorylase reaction with the study published by Russell Pressey from Plant
The experiments involved PH buffers of different pH were added to potato juice, water, and the enzyme catecholase. The mixture was then subjected to spectrophotometer at a wavelength of 420nm taking the absorbance readings. In the second experiment, a phosphate buffer of PH 7.0 was used in different measures together with different measurement of potato juice and the enzyme catecholase then subjected to the spectrophotometer at a wavelength of 420nm. The data collected inform of table and analyzed using descriptive statistics such as line graph and later interpreted, showing that PH and enzyme concentration do affect the rate of enzyme reaction