"Grilled Cheese Sandwiches"

Higher Glycemic Index Found in Non Organic Zea Mayas

Via Glycemic, Carbohydrate, Photosynthesis, and Enzyme Tests

Brandie Yancy

Shaneka Thomas

Nate Clay

Lisa Jess

LBS 145 Section 4

Joe Maleszewski

February 28, 2003

Abstract

To test the hypothesis that genetically engineered Zea Mayas, commonly referred to a corn, causes a higher increase in glycogen levels of humans as compared to organic corn; our research team subjected both types of corn to the following tests: glycemic index (GI) test, five carbohydrate tests, photosynthesis test, and enzyme test. In the GI test, we tested glycogen levels of ten individuals after consuming genetically engineered corn and again after consuming organic corn. We found that glycogen levels were higher after consuming genetically engineered corn than after consuming organic corn. To determine the makeup of the carbohydrate molecules in both genetically engineered corn and organic corn, we used the following five different carbohydrate tests; Benedict's Test, Barfoed's Test, Selivanoff's Test, Bial's Test, and Iodine Test. From these tests, we determined that genetically engineered corn and organic corn contained a carbohydrate with the following characteristics; non reducing, furanose ring, ketone , and di-polysaccharide. We conducted an Absorption Spectrum Test and determined that the absorbencies of both genetically engineered corn and organic corn peaked at 445nm. Finally, we tested both genetically engineered and organic corn for the presence of the enzyme polyphenoloxidase (PPO) and found PPO was not present in both. Our eight week research effort allowed us to make several conclusions about genetically engineered and organic corn. Foremost was the confirmation of our hypothesis, that organically grown corn has a lower GI than the genetically engineered corn.

Discussion

Many concerns about human health have been occurring more frequently. People are becoming aware of the various risk factors that may affect ones health, and as a result are trying to prevent bad health through means of adopting healthier eating habits. There are many programs that are developed to help people maintain good health through certain diet plans based on the daily carbohydrate intake. People with health problems such as diabetes often times follow very strict diets in order to maintain the appropriate glucose levels. However, what foods allow the body to have good glucose (blood sugar) levels, and what foods affect the body's blood sugar levels in a negative form? Throughout a seven week period, a group of students developed an experiment whose purpose was to test genetically engineered and organically grown corn, scientifically known as Zea Mays. Organic or natural grown foods are without any alterations, and genetically engineered foods have been altered with genes for better production (Bailey and Lappe', 2002). We also tested the Glycemic Index. The Glycemic Index classifies foods based on how they affect blood sugar levels following a meal. The index is also based on foods high in carbohydrates. Foods that are high in carbohydrates break down quickly during digestion and absorption which have high Glycemic indexes. On the other hand those foods that are low in carbohydrates break down slowly and release glucose into the bloodstream slowly which in return have low Glycemic indexes (Gilbertson et al., 2003). Because GI measurements are based on the raise in glucose levels after food intake, we hypothesized that non-organic Zea Mays after consumption would show a higher GI compared to the naturally grown Zea Mays. To explain, the body blood sugar levels would increase significantly. Other experiments were performed on Zea Mays to determine if it contained if any carbohydrates, photosynthetic elements, and the presence of an enzyme known as polyphenoloxidase (PPO).
We found throughout our research our experimental data supported our predictions that organic and non-organic Zea Mays contain carbohydrates. First, we performed five carbohydrate tests on genetically engineered Zea Mays, organic Zea Mays, and maltose, which was used as a control. Benedict's test (test for reducing sugars), Bial's test (test for the presence of furanoses), Selivanoff's test (test to differentiate between ketoses and aldoses), Barfoed's test (test that distinguishes between mono and disaccharides), and the Iodine Test for Coiled Polysaccharides, were the tests performed during the carbohydrate proton of the research. From the results of our five tests, we inferred the characteristics of the carbohydrates found in genetically engineered Zea Mays and organic Zea Mays. The genetically engineered Zea Mays contains a non-reducing, monosaccharide pentose furanose ketose sugar with the presence of starch (Table 4a-4f). Whereas, the organic Zea Mays contains a non-reducing, monosaccharide pentose furanose aldose sugar with the presence of starch (Table 4a-4f). These results were expected though. The slight difference in the make up of the carbohydrates found in genetically engineered Zea Mays compared to organic Zea Mays might be responsible for the increased GI levels. Genetically engineered Zea Mays have had foreign genes inserted into their genetic codes artificially that affect in one way or another blood sugar levels when digested in the stomach (Kennedy, 2003). The stomach secretes various enzymes that are involved in the digestion of proteins, and because artificial genes are in the corn, these artificial genes may affect the jobs of the enzymes resulting in the increase of glucose levels.
Second, we performed an absorption spectrum on the husks of both organic and non-organic Zea Mays. An absorption spectrum allowed us to compare the differences of non-organic and organic Zea Mays in absorbing wavelengths of light. We predicted that the both forms of the Zea Mays contained chlorophyll pigments that were capable of photosynthesis. This meant that the husks of the Zea Mays undergo photosynthesis. Our results from both spectrums followed that the chlorophyll pigments absorbed the most energy in the red and blue areas of the visible light spectrum (Figure 3). The husks appear green because this is the color that is reflected, meaning that in the visible light spectrum, for plant husks, the color green is not absorbed by light. Wavelengths that are used most effectively and efficiently in photosynthesis are at 680 nm and 700nm (Freeman, 2002).
Finally, we performed an enzyme test to determine if the enzyme polyphenoloxidase was present in both genetically engineered and organic Zea Mays. To do this we first weighed eight Zea Mays kernels for organic and non-organic. We then saturated four of the kernels with water, and four with catechol to determine if PPO was present. Our resulting data rejected our prediction that PPO was present in the organic Zea Mays and non-organic Zea Mays (Table 4). PPO is an enzyme that's responsible for the catalyzation of the oxidation of certain organic compounds. PPO is an enzyme that is found in a variety of plants and is responsible for the browning of damaged surfaces of fruits and vegetables. Polyphenoloxidase (PPO) was not found in either the organic or non-organic Zea Mays. Reasons why PPO was not present are unknown; however, we believe that the temperature at which our Zea Mays was stored may have had an effect on the PPO enzyme that caused the Zea Mays not to react to the catechol.
The three experiments noted above were conducted and used to determine the Glycemic Index of organic and genetically engineered Zea Mays. The GI food scale bases the GI values when the glucose levels equals 100. White bread (Wonder bread light sourdough bread) was used as the reference food in the experiment to give an idea of the differences in the blood sugars of the four participants (to reduce the influence of other factors all participants ranged from 5'3 to 5'9 in height and 130 to 180 pounds). White bread has a GI level equal to 70, although the GI for white bread varies based on the research found. Organic Zea Mays and genetically engineered Zea Mays were then implemented into the experiment to determine the effects of the differences in the production of genetically engineered Zea Mays and natural grown Zea Mays in concern with the GI of the individuals. Hypothesizing based on pre research; we predicted that the non-organic Zea Mays would show the higher GI levels. Corn has a GI level that ranges from 50 to 60.
In conducting the experiment we found that the reference food white bread raised the GI by one hundred percent over a period of 120 minutes. When testing the organic Zea Mays it was found that this Zea Mays GI was 46.826, whereas, the genetically engineered Zea Mays GI was 47.434. Thus, confirming our initial hypothesis that genetically engineered Zea Mays would increase the GI more than the organic Zea Mays (Figure1a) (Figure 1b).
Controversies exist with respect to the GI levels, and what value is an efficient amount of carbohydrate intake for a diabetic patient. The practicality of diets with a low Glycemic index (GI) is also controversial. According to the GI, our results suggest that non-organic Zea Mays have high glycemic indexes; meaning that the carbohydrates present in Zea Mays are broken down quickly. At the University of Sydney, the human nutrition unit reports that to have a high carbohydrate intake and low glycemic level is recommended for those with type 1 diabetes. Low GI means a smaller rise in blood sugar and can help control established diabetes. Theoretically, low-GI diets may limit food choice and increase dietary fat intake, but there is little objective evidence to support such a theory. Food intake and subjective appetite are inversely associated with the blood glucose response in the 60 min after consumption of carbohydrates. Carbohydrates with a high glycemic index (glucose, polycose, and sucrose) suppress subjective appetite and food intake, but those foods with a low glycemic index (amylose and amylopectin) do not (Gilbertson et al., 2003).
Recent research, however, indicates the GI may prove useful in other situations as well. Low GI-foods lower the concentrations of blood lipids in people with hyperlipidemia, and reduce the excretion of C-protein, which is released by the pancreas at the same time as and in amounts equal to insulin. Clinical studies also have demonstrated a diet containing low-GI carbohydrates can raise high density lipoprotein (HDL) cholesterol levels and lower the risks of diabetes, heart disease, colon cancer, and breast cancer (Obesity, Fitness & Wellness Week, 2002).
We believe that because the genetically engineered Zea Mays is genetically altered with artificial genes, these genes are responsible for the increased GI levels found in our results. For example, a protein found in genetically engineered Zea Mays is glufosinate ammonium, an active ingredient in Phosphinothricin Acetyltransferase (PAT). Glufosinate chemically resembles the amino acid glutamate and acts to inhibit an enzyme (Essential Biosafety, 2003). PAT may have oxidized within the body that to raised glucose levels of our tested subjects. Another possibility of the rapid increase of glucose levels provides that Bacillus Thuringiensis, a toxin contained in genetically engineered Zea Mays affect the glucose levels. The Bt toxin is used to stop the influx of molds, and is an insecticidal bacterium, marketed worldwide for control of many important plant pests (The Microbial World, 2003). This Bt toxin may have caused an increased rate in photosynthesis and ATP when compared with organic Zea Mays. The increased levels of ATP found in genetically engineered Zea Mays causes an increased level of carbohydrate as well. Other assumptions are that there were flaws in the design of our experiment. We followed the given procedure; however, those we tested may have not fasted for the required hours which are required for acceptable results. In addition to that, the food compared to determine which elevated glucose levels GI rating of food must be tested physiologically, and requires adequate developed experiments.
By these factors alone, it is not evident that genetically engineered Zea Mays is better nutrionally. The investigation did however; suggest that genetically engineered Zea Mays raised the glucose levels higher than organic Zea Mays. This might suggest that genetically engineered Zea Mays contains more energy than organic Zea Mays.