Investigate how PH Affects the Ability of Raw Meat to Absorb Water
I am planning an experiment to investigate how PH affects the ability of raw meat to absorb water.
· Independent Variable
The independent variable for this experiment is the PH of the solution the steak is marinated in. I will achieve a range of different PH values by using buffers set at PH 1, 3, 5, 7, 9. I predict that there will be an optimum PH where the steak will absorb the most water.
The amount of water absorbed by the raw meat will increase as you increase the PH up to the optimum and then decrease the PH as the PH increases past the optimum.
· Dependent Variable
The dependent variable for this experiment is the amount of water absorbed by the diced steak by
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Instead of calculating the difference in mass, I will calculate percentage change in mass to account for any small differences in mass.
Also a constant surface area of the diced steak is important, otherwise there would be a larger area for the solution to act on causing more tenderisation therefore altering the overall results.
The temperature at which the meat is marinated at would need to remain constant. At a higher temperature, molecules are moving faster therefore osmosis is more likely to occur. The experiment will be conducted at room temperature, although a more scientific method would be the use of an
incubator. I will conduct the experiment in the same place so that each test is experiencing the same temperature changes.
The time allowed for marination, each steak should be in the buffer solution for 12 hours all getting the same length of time otherwise a longer time could provide an opportunity for more water to be absorbed. Drying of the steak pieces, dab twice on each side. If some are dabbed more than the other it would alter the end percentage change in mass.
· Method
® Divide the diced steak into five equally sized piles.
® Using electronic scales weigh each pile to make the masses as similar as possible. Record the masses.
® Add 50ml of buffer solution PH1 to a beaker and repeat the process for the other buffer solutions.
® Put one set of diced steak into each beaker.
® Leave the 5 beakers for 12hours allowing the raw meat to
I know that osmosis will occur in the vegetables, but I am not sure of
For part B, 50 mL of an assigned 50 mL pH solution of either 1 M HCl, 1 M NaOH, lemon juice, and 50 mL of household bleach all in separate 250 mL beakers are to be used. For part C, a hot plate or ice are to be used to make the 1.0 mL assigned temperature specific water. This experiment will also use the 1.0 mL of 0.1 Phosphate buffer.
pH was recorded every time 1.00 mL of NaOH was added to beaker. When the amount of NaOH added to the beaker was about 5.00 mL away from the expected end point, NaOH was added very slowly. Approximately 0.20 mL of NaOH was added until the pH made a jump. The pH was recorded until it reached ~12. This was repeated two more times. The pKa of each trial are determined using the graphs made on excel.
We only added a small amount of HCl to the water and sodium chloride. We did not continue to add more HCl after a significant drop in pH was recorded. We added a total of 2 mL of HCl to both H20 and NaCl before the pH changed. The 1 gram solution of sodium acetate and acetic acid changed after a 8 mL, and the other two never dropped before we reached our total of 10 mL HCl.
weak bases). After ranking the pH of these solutions, you will then test your predictions in the laboratory.
pH is also known as a measure of hydrogen ions in a solution. A hydrogen ion is the nucleus of a hydrogen atom being split from its electron. Studying the pH of different types of soil being placed in a control group such as tap water will represent the acidity or alkalinity of the matter. The pH scale begins at 0 and goes all the way up to 14, pH 7 being its neutral point, which isn’t acidic or basic. A neutral point on the acidic scale is in the middle, anything lower than the neutral point (7), is acidic, and anything higher than the neutral point is considered basic or “alkaline”.
Figure 2 is a representation of the average saturation of each cuvette at a specific point time as a function. The y-axis shows the specific saturation points from figure 1, and the x-axis provides the different levels of pH. The pH scale provided on the x-axis ranges from 0 to 14, 0 being the most acidic and 14 being the most basic. The point chosen from figure 1 was the saturation levels of each cuvette at 110 seconds. The saturation point was chosen because in the previous graph at time 110 seconds the reactions of
To improve the results from the experiment buffer solutions that were not whole pHs could have been used e.g. pH 4.5, 5.5 etc. This would have provided more reliable results as a wider range of results would have been produced. Using pHs with decimals would also help to more accurately determine the optimum pH as the optimum may have been above or below the pH stated in the hypothesis; 8. In this experiment however the optimum is taken at 8 because the graph does not rise again.
To prevent fluctuation in the pH, a solution known as a “buffer solution” was used in the experiment. Buffer solutions are mixtures of at least two chemicals which counteract the effect of acids and alkalis. Therefore, when a small quantity of alkali or acid solution is added the pH of the enzyme doesn’t change.
must be above 8.5 and below 6.5. If the pH is too acidic, then the
A total of 1.5 mL was added to produce a pH of around 6. The mixture was stirred for an additional 30 minutes.
In addition, PH is the independent variable I am testing; therefore, its constancy is important. Variables in the experiment will need to be controlled and the following need to be kept constant * Concentration of trypsin * Amounts of reagents * Enzyme to substrate ratio
Using Graph 1: The Volume of Titrant Added in order to reach the Endpoint and the Corresponding pH Values, observe the vertical line of each titration and see the points in which the horizontal lines intersect it. These points give the
To calculate the pHC of each trial solution, the concentration of every ion in the
First, three titration curves and three second derivative curves were created to determine the average pH at the half-equivalence point from the acetic acid titrations. Titration curves were used as visuals to portray buffer capacity. The graphs and a table, Table 1, that showcased the values collected were created and included below. The flat region, the middle part, of Figures 1, 2 and 3, showed the zone at which the addition of a base or acid did not cause changes in pH. Once surpassed, the pH increased rapidly when a small amount of base, NaOH, was added to the buffer solution. Using the figures below and