Sugar, Absorption & Protein tests support processed Lycopersicon esculentum have disease-preventing capability

by

ÊWalker Foland

Marissa Hill

Sam Nass

Dmitry Rozin

Abstract

Many studies have been done that support the hypothesis that raw vegetables are more beneficial to overall health than processed vegetables.Ê However, new evidence is appearing that says that this might not always be the case.Ê We based our case study on determining whether processed tomatoes are better for disease prevention than fresh tomatoes.Ê The Barfoedâs, Selivanoffâs, and Iodine tests were performed to determine the carbohydrate make up of fresh and processed tomatoes.Ê The paper chromatography test for pigment was performed to determine varying concentrations of tomato pigment.Ê The absorption spectrum of lycopene was plotted to determine if lycopene was present in the samples. The Bradford assay was performed to see which tomato had more protein.Ê The carbohydrate tests showed that processed and fresh tomatoes had identical sugars.Ê The absorption spectrum showed that fresh and processed tomatoes had the same absorbencies at 470nm.Ê From the Bradford assay, we found that fresh and processed tomatoes have the same amount of protein.Ê We analyzed the data from the tests and decided which type of tomato we thought was more helpful in the prevention of disease.Ê From our data, we discovered that both tomatoes contained the same sugars and amounts of protein from the tests ran.Ê Our lycopene test showed that processed tomatoes had less lycopene than fresh tomatoes, which contradicts what we had predicted.Ê Therefore, we cannot conclude that one type of tomato is more beneficial to preventing diseases.Ê

Discussion

The goal of our study was to determine which type of tomato was more effective in disease prevention, processed or fresh. Our treated tomato group was boiled in water for 10 minutes at 100 degrees Celsius, making it processed. Our untreated tomato groups were kept fresh; nothing was performed on it other than surface cleaning with water at room temperature. Our hypothesis was that the processed tomato group would be more effective in disease prevention than the fresh tomato group. We predicted that the boiling process itself would alter carbohydrate content, photosynthetic properties in the pigment, and protein levels in the tomatoes. We came to this prediction because other studies have shown that boiling vegetables can significantly lower levels of vitamins and minerals, therefore, we deduced that other components could be altered as well (Makris et. al., 2001).Ê After all of our research we found that our results did not clearly support our hypothesis. We used a series of tests to determine the validity of our predictions. The first of three sets of tests was that of carbohydrates which contained three parts, the Barfoedâs, Selivanoffâs and Iodine tests. The second set consisted of two parts. One was a pigment test using paper chromatography. The second was an absorbency test in order to observe the amount of lycopene. The third of these sets consisted of one test to determine the amount of protein in the tomatoes.

Our first experiment was Barfoedâs test. This test was used to observe the presence of monosaccharides, disaccharides, and polysaccharides (Krha et. al., 2004).Ê This procedure uses lower pH levels and a shorter heating duration. The monosaccharides react much faster than the disaccharides and polysaccharides producing a reddish-orange precipitate. If no reaction occurs that indicates disaccharides and polysaccharides (Krha et. al., 2004).Ê Our results showed us that both processed and fresh tomatoes have monosaccharides because of the reddish-orange precipitate formed (Table 1 and Figure 1).Ê

In order to make this test more conclusive, in the future, we would weigh the precipitate yielded from the Barfoedâs test. This would give us a quantitative aspect to this test and could possibly show the differences between the amount of monosaccharides in processed and fresh tomatoes at a much more precise level.

Our second experiment within the carbohydrate study was Selivanoffâs test. This was used in order to determine the levels of ketose versus aldose sugars (Krha et. al., 2004).Ê Using a solution of resorcinol in concentrated hydrochloric acid, we heated the solutions with the tomato extract. If any reaction occurred, a red solution is produced due to furfural or hydroxymethylfurfural. If the reaction occurs within one-minute, monosaccharide ketose is present.Ê If the reaction takes place in approximately one minute, a disaccharide ketose is present.Ê If the reaction takes longer than one minute, then disaccharide aldose is present (Krha et. al., 2004).Ê We found that there were monoketoses in both processed and fresh tomato groups (Table 1 and Figure 2).

Our final experiment in the carbohydrate analyses was the iodine test. The iodine test is used to determine the presence of starch. Iodine happens to only react with the starch to form a bluish/black solution (Krha et. al., 2004).Ê We found that there was no starch present in either processed or fresh tomatoes because our solutions did not change color (Table 1 and Figure 3). Therefore, processing the tomatoes appears to have made no difference in the presence of carbohydrates.

After the carbohydrate analysis, we moved onto our experiments concerning photosynthesis.Ê We performed a pigment test on our tomatoes to determine loss of photosynthetic qualities. Recent studies indicate that during thermal processing plant cell walls burst (Dewanto et. al., 2002). This could result in a loss of pigment. The idea of the cell walls breaking and losing pigment could mean a loss of many other enzymes and nutrients as well. We found carotene pigment in the processed and fresh tomato groups (Figure 4).Ê Tomatoes, even though they do not contain the pigment chloroplast, should contain carotene.Ê We predicted that the rate of flow values would be less in the processed tomatoes than in the fresh tomatoes.Ê Our results showed that the rate of flow values were about the same for both groups, however, the processed tomato ratios were slightly higher than the fresh tomato ratios (Table 2).Ê

In this particular study, we also chose to test for the presence of lycopene through the use of the spectrophotometer.Ê A recent study suggests that lycopene activity is heightened during treatment, in which case raises the anti-oxidant levels of the tomato (Dewanto et. al., 2002). We found that there was actually less lycopene in the processed tomato group than the fresh tomato group by comparing their absorbencies to that of lycopene pills (Table 3 and 4).Ê This is not what we anticipated.Ê We may have obtained different results if we had used a different type of lycopene pill.Ê We originally planned to use a chalk type pill that would be dissolved easily.Ê However, because of difficulties with shipping, we had to use a gel coated lycopene pill.Ê Because the gel pill could only be dissolved in hydrochloric acid, this may have affected the amount of lycopene we actually added to our solutions.ÊÊ

Our last experiment was called the Bradford assay (Krha et. al., 2004). This tests for protein levels. We found that processed and fresh tomatoes had similar protein levels (Table 6).Ê This information was expected. We did not perform a qualitative calculation of the exact amounts of protein in the tomatoes because the absorbencies were so close, we considered them identical. We conclude that processing makes no difference in protein content.Ê

After all of our tests and data collection, we do not feel that we have enough data to determine if processed tomatoes are more effective in disease prevention than fresh tomatoes. If higher levels of lycopene in the processed tomatoes had been found, we feel that would have outweighed the abundance of monosaccharides found in both types of tomatoes.ÊÊ According to research done at Cornell University, lycopene is an antioxidant, which heightens in activity during processing. This is due to the cis and trans isomers of lycopene. Before processing the lycopene it is generally in its trans conformation, which is less effective in absorbing free radicals. The heat and churning of processing the tomato solution breaks a pi bond in the molecule, which causes the cis conformation to become the major product.Ê This increases overall antioxidant activity in the tomato (despite physically less lycopene) making it more nutritious, helping to prevent cancer (Dewanto et. al, 2002). Because of proteins prominent importance in the diet, the presence of protein in all tomatoes was important in the broad picture of our question.Ê

To test the hypothesis that increased lycopene is more significant than the lack of protein and presence of monosaccharides, we will have to perform more tests. Such tests would include a quantitative data collection of Barfoedâs test precipitate.Ê An absorption spectrum for lycopene would be done with non-gel coated lycopene pills.Ê Also, an analysis of those given quantities on the prevention of disease would be performed. A test to compare the presence and effectiveness of the cis and trans versions of lycopene would have to be conducted as well. These results would then have to be compared to lost lycopene levels to see whether the increased activity outweighs the lack.