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Students Anna Devathasan and Jenny Suo tested the blackcurrant cordial against rival brands to test their hypothesis that cheaper brands were less healthy. Instead, their tests found that the Ribena contained a tiny amount of vitamin C, while another brand's orange juice drink contained almost four times more.
The girls were both 14 and students at Pakuranga College in Auckland when they did the experiment in Given Ribena's advertising claims that "the blackcurrants in Ribena have four times the vitamin C of oranges", they were astonished and wrote to the manufacturers, GlaxoSmithKline GSK.
When they got no response, they phoned the company, but were given short shrift. They just said it's the blackcurrants that have it, then they hung up," Jenny said.
But then the girls' claims were picked up by a TV consumer affairs programme, Fair Go, which suggested they take their findings to the commerce commission, a government watchdog. GSK said the girls had tested the wrong product, and it was concentrated syrup which had four times the vitamin C of oranges.
But when the commerce commission investigated, it found that although blackcurrants have more vitamin C than oranges, the same was not true of Ribena. It also said ready-to-drink Ribena contained no detectable level of vitamin C.
The Australian competition and consumer commission said last week that claims on the nutrition information panel of Ribena's ready-to-drink cartons implied that the product had four times the vitamin C of orange juice drinks, when this was not correct.
The girls have since visited GSK to be thanked "for bringing it to our attention". GSK said in a statement yesterday that concerns about vitamin C only affected some products in Australia and New Zealand.
This testing has confirmed that Ribena drinks in all other markets, including the UK, contain the stated levels of vitamin C, as described on product labels.Vitamin C (ascorbic acid) is an antioxidant that is essential for human nutrition.
Vitamin C deficiency can lead to a disease called scurvy, which is characterized by abnormalities in the bones and teeth. Here is an example of how you can measure the concentration of ascorbic acid (vitamin C) in your original sample of fruit.
Suppose you started with 10 g of tissue and made an extract in 50 cm 3 of water and then in the titration a 1 cm 3 sample of your extract required cm 3 of % DCPIP solution. As each cm3 of % DCPIP (MWt ) solution is equivalent to x g ascorbic acid (MWt .
Mar 29, · Other results indicate a vitamin C content of 33–50 mg/ mL for orange juice (Valencia) obtained by squeezing the fruits. For the grapefruit juice (Florida), also obtained by fruit pressing, the ascorbic acid content varies between 38 and 56 mg/ mL [ 47 ].
Testing Foods for Vitamin C (Ascorbic Acid) Introduction A blue substance called 2, 6-dichlorophenolindophenol (or DCPIP for short) acts as an (vitamin C). DCPIP solution can be used to test for the presence of vitamin C in foods (but not for other vitamins which are .
Measure the vitamin C content of a sample of fruit juice by measuring the volume of the sample required to decolourise a solution of DCPIP.
Calibrate the results by comparison with a . Measuring the Vitamin C content in a variety of fruit juices Background Information Vitamin C, also called ascorbic acid, is a water soluble vitamin.
It is a powerful reducing agent that is able to decolourise blue DCPIP (dichlorophenol indophenols).