Hypothesis: The amount of antioxidants would decrease as the number of brews increases.
An antioxidant is a molecule that inhibits the oxidation of other molecules. Oxidation is a chemical reaction involving the loss of electrons. Oxidation reactions can produce free radicals. These radicals can start chain reactions. When the chain reaction occurs in a cell, it can cause damage or death to the cell. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit the oxidation reactions, hence prevent the damage caused by oxidation to cells. Therefore, if we have insufficient levels of antioxidants, the oxidative stress may damage or kill cells, leading to diseases, such as cancers. Therefore brewing tea has become popular nowadays, as antioxidants such as vitamin C and polyphonols are released from tea leaves during brewing.
Hence people claim that drinking tea could prevent diseases like cancers. In this experiment, DCPIP solution is used to test the amount of vitamin C in the tea sample. DCPIP solution is a blue substance that would turn from blue color to pink with acids while turn from blue color to colorless with ascorbic acid (vitamin C). Therefore the DCPIP solution is used to test the concentration of vitamin C in a certain substance, by measuring the amount of substance needed to decolorize the DCPIP solution.
When more of the substance is required to decolorize the substance, it means that the concentration of vitamin C in the solution is low; if less amount of the substance id required to decolorize the DCPIP solution, it means that the substance contain a higher concentration of vitamin C. Investigation: In this lab, I will investigate in the concentration of vitamin C in a sample of fermented tea and a sample of unfermented tea, and also the concentration of vitamin C in different number of brews of the two sample. Design of experiment: In this experiment, I will brew the two samples of tea for four consecutive times. Then, I will look at the amount of tea sample needed from each brew of the two samples to decolorize the DCPIP solution.