Vitamin C Content of Fruit Juices

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BIOLOGY LABORATORY REPORT

Name : Amirah Binti Shaharuddin
IC No.: 930428-08-5326
Student ID: 2012400466
Group : 13M1
Title : The Vitamin C Content of Fruit Juices Lecturer : Madam Rita Rohaizah binti Sohari

TITLE: THE VITAMIN C CONTENT OF FRUIT JUICES

INTRODUCTION

Vitamin C which is also known as ascorbic acid is an essential nutrient for human. It is a water-soluble vitamin that is necessary for normal growth and development. Water-soluble vitamins dissolve in water. Leftover amounts of the vitamin leave the body through the urine. That means a continuous supply of vitamin is needed in daily diet. Vitamin c is an odourless white solid with the chemical formula of C6H8O8. Vitamin C is one of many antioxidants. Antioxidants are nutrients that block some of the damage caused by free radicals .Free radicals are made when your body breaks down food or when you are exposed to tobacco smoke or radiation .The build up of free radicals over time is largely responsible for the aging process. Free radicals may play a role in cancer, heart disease, and conditions like arthritis. The pharmacophore of vitamin C is ascorbate ion which is an anti-oxidant that protect the body against oxidative stress. Ascorbate acts as a reducing .When there are more free radicals compared to an anti-oxidant in the body, a human is under the condition called oxidative stress Vitamin c is easily oxidised to form dehydroascorbic acid (DHAA) causing the oxidation of the vitamin to be readily reversible. Vitamin C is a good reducing agent and therefore it is easily oxidised. Vitamin C can be detected by titrating it against a solution of an oxidizing agent. A common type of oxidizing agent that is used to test for presence of Vitamin C is DCPIP solution.

Structural formula of vitamin C

SOURCES OF VITAMIN C
All fruits and vegetables contain some amount of vitamin C.
Foods that are the highest sources of vitamin C include:
* Cantaloupe
* Citrus fruits and juices, such as orange and grapefruit * Kiwi fruit
* Mango
* Papaya
* Pineapple
* Strawberries, raspberries, blueberries, cranberries
* Watermelon
Vegetables that are the highest sources of vitamin C include: * Broccoli, Brussels sprouts, cauliflower
* Green and red peppers
* Spinach, cabbage, turnip greens, and other leafy greens * Sweet and white potatoes

DEFICIENCY OF VITAMIN C
Too little vitamin C can lead to signs and symptoms of deficiency, including: * Bleeding gums
* Decreased ability to fight infection
* Decreased wound-healing rate
* Dry and splitting hair
* Easy bruising
* gingivitis (inflammation of the gums)
* Nosebleeds
* Possible weight gain because of slowed metabolism
* Rough, dry, scaly skin
* Swollen and painful joints
* Weakened tooth enamel
* scurvy.

HOW DCPIP WORKS
DCPIP, redox dye usually used as a monitor of the light reactions in photosynthesis because it is an electron acceptor that is blue when oxidized and colorless when reduced. The dye changes color when it is reduced, due to its chemical structure. The nitrogen atom in the center of the molecule is the atom that accepts electrons, and it changes the double N-C bond to a single bond, which forces bonds between carbons in the entire left ring to change. This microscopic shift in the DCPIP structure causes the macroscopic change in color, from dark blue to colorless. The amount of DCPIP reduced can be found by measuring the solution's light transmittance with a spectrophotometer. DCPIP can also be used as an indicator for Vitamin C . If vitamin C, which is a good reducing agent, is present, the blue dye, which turns pink in acid conditions, is reduced to a colorless compound by ascorbic acid.

DCPIP (blue) + H+ ——→ DCPIPH (pink)
DCPIPH (pink) + Vitamin C ——→ DCPIPH2 (colourless)
C6H8O6 +...
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