Analysis of the differences of percentage of vitamin C (ascorbic acid ) between the fresh orange juice and artificial orange juice (Sunkist). Problem statement :
Does have different types of fruit juice contain similar amount of vitamin c ? Objevtive:
To analyse the concentration and percentage of different food sample by using titration method and state whether the percentage and concentration of vitamin C. Methodology:
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) + VitC ——→ DCPIPH2 (colorless)
C6H8O6 + C12H7NCl2O2 ——→ C6H6O6 + C12H9NCl2O2
In this titration, when all the ascorbic acid in the solution has been used up, there will not be any electrons available to reduce the DCPIPH and the solution will remain pink due to the DCPIPH. The end point is a pink color that persists for 10 seconds or more. Pharmacological experiments suggest that DCPIP may serve as a pro-oxidantchemotherapeutic targeting human cancer cells in an animal model of human melanoma; DCPIP-induced cancer cell death occurs by depletion of intracellular glutathione and upregulation of oxidative stress.
Literature review :
When most people think of Vitamin C in foods, their minds go immediately to citrus fruits, especially oranges. While citrus fruits are a good source of Vitamin C, some other fruits have even more of this health-promoting vitamin. Juices, rather than the whole fruit, are a quick way to get Vitamin C, but the vitamin content degrades over time after juicing. Vitamin C is a term for the chemical ascorbic acid. In processed citrus products, additional Vitamin C may be added, labeled as ascorbic acid. Citrus fruits include oranges and related fruits such as tangerines and satsumas, limes, lemons, grapefruit, kumquats and many others not commonly available in Western markets (http://www.livestrong.com/article/127884-concentration-vitamin-c-citrus-fruits/) May 20, 2010 You know you need to eat fruits because they contain nutrients that help keep you healthy. But if you don't eat your fruit soon after it's been picked, you may be losing out on some of the goodness. Vitamins, such as vitamin C, are susceptible to light and heat. While you may be eating that kiwi to help meet 100 percent of your daily value for vitamin C needs, if the kiwi has been sitting around for a few weeks, you may not be getting as much as you think. Vitamin C is an essential water-soluble vitamin. As a water-soluble vitamin, any excess vitamin C you consume is excreted in your urine. This also means that vitamin C is not stored in your body and must be consumed regularly to meet your needs. Vitamin C is needed for the synthesis of collagen, a protein that helps with wound healing. Vitamin C also supports immune health and normal growth and
development. It is also an important antioxidant, protecting your cells against oxidation, and decreasing your risk of chronic diseases such as cancer and heart disease. Your daily vitamin C needs vary depending on your age and gender. Adult men need 90 mg of vitamin C a day, and adult women need 75 mg a day, according to the Office of Dietary Supplements. Libby Swope Wiersema, Does the Amount of Vitamin C Change When a Fruit Gets Older?(http://www.livestrong.com/article/517371-does-the-amount-of-vitamin-c-change-when-a-fruit-gets-older/) Aug 18, 2011 Technique :
Measure and determine the volume of standard vitamin c solution / fruit juices needed to decolourise of 1ml of DCPIP .Calculate the vitamin c content of juice by comparing it with the standard vitamin c solution. Percentage of ascorbic acid in fruit juice = Volume of 0.1 % ascorbic acid × 0.1 Volume of fruit juice
Concentration of ascorbic acid...
Please join StudyMode to read the full document