ORAL PRESENTATION

Good morning! My name is Emma Polonio Alcalá and I wouls like present you my research project The vitamin C in orange juice.

Regarding the choice of research project topic I wanted a topic related between biology and chemistry, because they are my favourite subjects. So I asked to my teacher, Assumption Aurich, and we find the team of vitamin C in orange juice. I was interested in this topic, because I usually consume it.

My objectives were:

• What factors affect the vitamin C in natural orange juice.

• See the difference of quantity of vitamin C between in natural orange juice and elaborated orange juice.

As for the methodology:

• First I did a search to know that I had to look.

• Later, I did the practice to determining ascorbic acid with the coloring 2,6-diclorofenolindofenol.

• Finally, I did the theoric part.

Vitamins are organic substances that we are need in small amounts for proper functioning of cellular metabolism. In total there are thirteen, which are divided according to their solubility: the water-soluble, and lipo-soluble. As you can see the vitamin C is found in the water-soluble.

Vitamin C was discovered thanks to the disease caused when there is deficiency, scurvy, but it was not until 1928 that Albert von Szent-György Nagyrápolt was isolated vitamin C and he studied their biological functions. In 1934, Walter Norman Haworth synthesized and determined its structure.

Vitamin C is an organic substance, water-soluble and it derivative of a hexose and it acts as an enzyme cofactor performing accions of agent of oxidation-reduction, nuclear and mitochondrial and acts as an antioxidant in the body. It's necessary for growth, development and survival for living. For this reason, we synthesized it, but the higher primates and Cavia porcellus (guinea pig) can't synthesized it and they obtain it from the diet.

Regarding the different types of juice, we have:

• The natural fruit juices.

• The concentrate fruit juice in force.

• The concentrate fruit juice concentrate.

• dehydrated fruit juice.

• The nectar fruit.

The main objective of the practice was to achieve the objectives set, as I said, see the factors affecting the vitamin C in natural orange juice and see the difference between of quantity of vitamin C in natural orange juice and elaborated orange juice. The practice can be divided into four parts:

• The first practice is to prepare the coloring and a standard solution of ascorbic acid to standardize it. I obtained these results and from the calculations that you can see we know that 1.15 mL of the coloring is 1 mg of ascorbic acid.

• The second practice is to calculate the quantity of vitamin C in natural orange juice. We obtained these results and from the calculations that you can see we know there are 41.47 mg of ascorbic acid per 100 mL of juice.

• The third practice is to see what factors affect the ascorbic acid that is found in orange juice. Here we see the different samples and results. With this graph we can see how the sample A and B, ascorbic acid is oxidized and the reduced of quantity of vitamin C. Also shows that the E, F, G and H have mold and they undergone acidification.

• The fourth practice is to see what differences of vitamin C in differents marks of orange juice.

Regarding the conclusions:

• My objectives have been well achieved.

• The temperature affects the oxidation of vitamin C, when increases the temperature, increases oxidation and decreases the temperature decreases the oxidation.

• The bacteria that cause the molds, acidification of juices.

• Don Simon has more vitamin C of the juices analyzed.

Do you have any questions?

ORAL PRESENTATION OF VITAMIN C IN ORANGE JUICE

SELF AVALUATION: 0,5p of 1p.

I had a horrible oral presentation of my research project, but my presentation have a lot of difficult vocabulary that other didn't have. So, I think that I have a puntuation on 0,5.