Discussion: (Amy Lacy, revised by Afra Ali and Ted Stachon)

We hypothesized that organically manufactured orange juice is more similar to that of natural, fresh squeezed orange juice than a standard store bought brand in composition, due to many factors during processing. We believe one reason for this variance is due to pasteurization, which takes out the harmful effects but preserves, and in some cases, adds vitamins, minerals, and enzymes (Gill and Ferreres, 2002).

ÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝ In order to identify organic compounds in the three types of orange juice we used the Benedicts test, Bials test, Iodine test and Selivanoffís test.Ý The Benedicts test looked for reducing sugars in the three types of orange juices.Ý After performing the Benedicts lab, all three types of orange juices both in 50% and 25% dilution, exhibited color change from blue to a blood red color and formed a precipitate.Ý Due to these results we concluded that Odwallaís Organic orange juice, Tropicana and freshly squeezed orange juice we assume are free of any aldehyde or ketone groups and unreduced copper precipitates.Ý The Bialís test looked for a furanose ring present in the three types of orange juices.Ý In the 50% dilution the Tropicana orange juice as well as the freshly squeezed and Odwallaís orange juice exhibited a color change from yellow to dark- green and formed a precipitate in trial two. However, in trial one and three Tropicana still exhibited a color change from yellow to a dark- algae color with a precipitate formed while the freshly squeezed and Odwallaís orange juice exhibited a color change from yellow to an olive green color with a precipitate. When the test was performed with the 25% dilution, Tropicana had a color change from yellow to a consistent dark green with a precipitate in all three trials. Odwallaís and the freshly squeezed orange juice changed from a yellow color to olive green with a precipitate in all three trials. After performing the Bialís lab, we found that furanose (dark green color with precipitate) was only present in Tropicana orange juice and that pentose- furanose (olive green color with precipitate) was present in Odwallaís and freshly squeezed orange juice. These results, gave us reason to believe that Odwallaís and the freshly squeezed orange juice are closer in glucose composition. Iodine testing was performed to detect the starch levels.Ý Unfortunately, when we performed the iodine test none of the three types, in 25% dilutions, remained yellow indicating starch.Ý This is not to say no starch is present, just that our test may not have been strong enough to detect a color change.Ý The Selivanoffís test helped us differentiate between ketoses and aldoses in our three types of orange juices in 50% and 25% dilutions. After performing the Selivanoffís test, all three types of orange juices both in 50% and 25% dilutions exhibited a red color change with a precipitate that formed in less than one minute. Freshly squeezed and Odwallaís turned red with a precipitate at almost the same time while Tropicana followed close behind. This led us to believe that Tropicana, Odwallaís and freshly squeezed are all composed of a sugar with ketoses.Ý

Using paper chromatography testing, we wanted to determine what pigments were present in the orange juices and the orange peal.Ý After concluding our tests we were unable to detect any pigments.Ý It was not that there are not any pigments in the orange juices or orange peel we just couldnít detect them using this test.Ý However, there was a solvent front on all strips indication movement, showing that the test did in fact work but just did not reveal any pigments.Ý We think that this could have possibly been effected by pesticide residue on the orange peel.

During our enzyme lab we used Salivary Amylase to detect enzyme activity.Ý We started with a stock solution of salivary amylase and added it to a 50% solution of the three types of orange juices.Ý We then performed the carbohydrate tests, Benedicts and Selivanoffís to detect for this activity.Ý In the benedicts test the reaction times varied between all of the different orange juices with salivary amylase verses the orange juices without salivary amylase.Ý In the Odwallaís orange juices the reaction was 8.81 seconds faster, the Tropicana orange juice was 8 seconds faster, and the fresh squeezed orange juice reaction was 8.17 seconds faster.Ý We believe this is due to the fact that salivary amylase is an enzyme, which therefore speeds up the reaction time of the Benedicts test.Ý When we performed the Selivanoffís test we found similar results.Ý In the Odwallaís orange juices the reaction was 3.46 seconds faster, the Tropicana orange juice was 4.36 seconds faster, and the fresh squeezed orange juice reaction was 2.44 seconds faster.Ý We believe this is also due to the fact that salivary amylase increases the reaction time.

ÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝ During our experiment we observed different forms of biology at work. Including how the pasteurization, or varying levels of pasteurization could have changed the results of the tests.Ý During pasteurization there is a detectable loss of some of the components in the fresh squeezed as opposed to the Tropicana store bought and the Odwallaís Organic orange juice. Organic orange juice, specifically Odwalla brand, is pasteurized using theí flash pasteurizingí method. This procedure involves heating the product to a temperature ideal for killing bacteria but at a much faster rate than the standard pasteurization process used for Tropicana. This method retains many of the beneficial vitamins that would otherwise be cooked out of the product. (Odwalla.com, 2003) ÝÝThe three types of orange juices we tested all had different levels and lengths of pasteurization.Ý

ÝÝÝÝÝÝÝÝÝÝÝ Some of the weaknesses in our experiment could have been that we didnít test enough aspects of the orange juice to really know all of the differences.Ý Pasteurization might not be the only factor that changes the variance of the orange juice, even though this is the one that we focused the most on during our research, being that it is an increased health concern.Ý The portion of juice we used during each test could have had different concentrations that would in turn change our results, giving us inaccurate readings.Ý Another weakness could have been where the oranges themselves were grown, and how they were grown.Ý Having no way of knowing this information, we had to assume that all growing conditions were the same.Ý

We understand the importance of orange juice and how beneficial it can be as a key factor in our daily diets.Ý Orange juice helps with lowering blood pressure, provides us with calcium as well as other beneficial nutrients and has a great taste.Ý Through our experiments we learned that nothing beats freshly squeezed orange juice but when one is in a time crunch, one should opt for Organic orange juice instead of the store bought brand. Our original hypothesis was that organically manufactured orange juice is more similar to that of natural, fresh squeezed orange juice than a standard store bought brand in composition.Ý We believe that after the various carbohydrate, enzyme and photosynthetic testing that our hypothesis was accurate.Ý During our testing organically processed orange juice did show more similarities to that of fresh squeezed than did the store bought brand.

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