Differences in Chemical Environments between Habanero, Jalapeno, and Bell Peppers

By: Nik Vuljaj, Peer Karmaus, Dan Gutteridge

LBS 145

Su1 Group 2

Dr. Douglas Luckie

October 20, 2002

Abstract–NikVuljaj

There are a lot of known species that belong to the Genus Capiscum. This study examined the differences between three of the species, which were selected based on their spiciness, habanero, jalapeno and bell pepper. It is known from previous research experiments that a class of compounds known as capsaicinoids performs the major role in the spiciness of peppers. We believed that not just the difference in capsaicinoids concentration, but the difference in carbohydrates concentration, light absorption, presence of polyphenoloxidase (PPO) enzyme, and environmental effects on the PPO enzyme might also influence how spicy these peppers are. We ran different carbohydrate tests to test for the presence of the different sugars, used spectrophotometry for the light absorbance, and tested for PPO using catechol substrate. The peppers were collected fresh from a farm in Grand Blanc, MI where they grew in the same conditions. The significant finding was that jalapeno and bell pepper had no presence of starch and that bell pepper had no monosaccharides present. The PPO test showed that only habanero and jalapeno pepper had some PPO enzyme present, but the environmental effects were hard to determine. The light absorption showed that habanero pepper has the highest pigment density. Based on the data gathered we were not able to make a specific conclusion whether our results contradict or support our hypothesis. We did come to the conclusion that more tests needed to be included in this study in order to specifically determine the answer to the hypothesis given.

Discussion– Nik Vuljaj, Dan Gutteridge, Peer Karmaus

           Performing this experiment we tested if the carbohydrate concentration, light absorption, presence of polyphenoloxidase (PPO) enzyme, and environmental effects on the PPO enzyme might correlate to the differences in the spiciness between habanero, jalapeno, and bell peppers. The study question concerned primarily with the concentrations of parameters mentioned above other than the concentration of capsacinoids, the class of compounds that adds heat to peppers, and if those concentrations also influenced the spiciness of the pepper along with capsacinoids. From previous research we found that capsaicinoids also inhibit growth in certain bacteria and we questioned if capsaicinoids might inhibit carbohydrate concentration, enzyme activity, and light absorbance in habanero, jalapeno, and bell peppers. (Dorantes et all, 2000) We believed the carbohydrate concentration, light absorption, presence of polyphenoloxidase (PPO) enzyme, and environmental effects on the PPO enzyme were related to the level of capsaicinoids in peppers and their concentrations directly influenced or contributed to the overall spiciness of the peppers. The prediction was that the different carbohydrates, light absorption, presence of polyphenoloxidase (PPO) enzyme, and environmental effects on the PPO enzyme would affect the spiciness of the peppers.

           Based on the data collected in “Benedict’s test”, all three peppers contain reducing sugars (Table 1, Figure 3). “Selivanoff’s test” did not result in a clear difference of sugars in the three tested peppers, indicating that all three contained ketoses (Table 1, Figure 8). “Bial’s test” also did not result in a difference of sugars in the three tested peppers, indicating that all three contained pentose-/hexose-(or higher) furanoses (Table 1, Figure 11). All three tests indicated that reducing sugars, ketoses and furanoses may not be related to the spiciness of peppers. All three tests appeared to have same results for all three peppers and since there was no difference in these results we rejected our hypothesis that the different sugars would be found in the peppers of different spiciness.

           Contrarily, “Barfoed’s test” indicated that Habanero peppers had the highest concentration of monosaccharides, Jalapeno peppers also contained monosaccharides, however Bell peppers did not test positive for monosaccharides (Table 1, Figure 6). “Barfoed’s” supports that the spicier the pepper the more monosaccharides are present. Therefore confirming that higher concentrations of monosaccharides may be associated with a higher capsaicinoid content, which is directly related to the spiciness of the pepper. Based on our findings we believe that our above explanation is true, but we would need further testing to assure our explanation is correct.

           In addition to “Barfoed’s test”, the “Iodine test” indicated that only in the spiciest peppers, Habanero, starch was present (Table 1, Figure 14). The presence of starch appears to be related to the level of capsaicinoids present, because habanero peppers have the highest concentration of capsaicinoids (hence they are the spiciest ones out of the three tested) and it indicates that starch might be another parameter that might influence how spicy the peppers are.

The percent of pigment absorbance in all three of the species turned out to be quite different. The percent absorbance in bell peppers achieved the highest value at the wavelength of 400 nm reaching the percent absorbance of 46%. The percent absorbance in jalapeno peppers achieved the highest value at the wavelength of 400 nm reaching the percent absorbance of 24%. The percent absorbance in habanero peppers achieved the highest value at the wavelength of 400 nm reaching the percent absorbance of 20%. The results for habanero pepper rejected our hypothesis where we predicted that habanero peppers would have the lowest pigment absorbance, because they have the lightest physical characteristics. We believe that this hypothesis rejection was due to the nature of the habanero extract we made that was lot more turbid than the extracts of jalapeno and bell peppers. Due to these results better solutions of the extract should be made in

Table 1: Carbohydrate Test Report

This table summarizes the six carbohydrate tests for bell, jalapeno, and habanero peppers at 50% pepper extract solution. The only or most of the visual result could be obtained from 50% solution due to concentrations of molecules that were tested for. A color change or precipitate indicates a positive result for the presence of the sugar tested.