Results

Lauren Beach, Katlin Daugherty, and Brian Farber

In the first independent lab, we performed five tests to show the sugar content of apples and pears. In Benedict's we saw a precipitate form in both the apple and pear

solutions. In Barfoed's the solutions became much darker in the given time for both solutions. In Selivanoff's test both of the solutions turned a dark purple in under 30

seconds, in the Bial's test both of the solutions turned a dark brown, and in the Iodine test no change occurred for both solutions (Table 1).

Table 1: The sugar content of the two fruits was tested. The observations of all three trials of each of the five tests performed are shown.
The tests were performed on the slurry solutions that were made out of the fruits.

Table 2: The results of the glucose meter test. A CVS/Pharmacy Complete Blood Glucose Monitor was used to test the glucose content of both the apples and pears.

Our absorption spectrum results for our independent research shows that apples and pears both have peaks and valleys in the same places. Apple absorption spectra,

however, remain consistently lower than pear absorption spectra (Figure 2). Also results for the first week of Lab 2 when we performed these same tests on spinach

leaves, our positive control (Figure 3).

Figure 2: Graph of the absorption spectrum for the analysis of apples and pears. Two dilutions of each apple and pear leaves were tested for their absorbance at wavelengths of 400 nm to 700 nm every 15 nm.

Figure 3: Graph of the absorption spectrum for the analysis of spinach, our positive control. Two dilutions of the spinach was tested for their absorbance at wavelengths of 400 nm to 700 nm every 15 nm.

The results for our action spectrum, or Hill reactions, unlike the results for our other independent experiments show different patterns in apples and pears. The results

showed Apples to absorb white light, red light, no light, then blue light; and pears to absorb blue light, red light, white light, then no light (Table 4).

Table 4: The hill reaction determined by the action spectrum for apple and pear leaves.

Table 5: The observations made during the testing of pH and presence of PPO for apples and pears.

Figure 6: A Picture of the Effects of pH on the PPO enzyme in apples. For this test the apple slurry solution was added to different pH buffers and the results of the absorbance was recorded. The appearance of the solutions is shown above.

In the tests of the effects of heat and inhibitors our control for the apples and the pears turned a slight brown color adding copper ions to the boiled solution turned the

apple and pear solutions clear. Adding phenylthiourea to a test tube also turned the two fruit solutions a powdery white (Table 6).

Table 6: The effect of heat and inhibitors on the apple and pear slurries.