Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fruit juices contain more vitamin C than their labels indicate

07.10.2009
A team of pharmacists from the University of Santiago de Compostela (USC) has established that the levels of vitamin C in many fruit juices and soft drinks are far higher than those indicated on their labels by the manufacturers. This finding has been possible owing to a new technique developed by the researchers to determine the content of vitamin C in these kinds of drinks.

Ascorbic acid or vitamin C is a natural antioxidant in fruits and vegetables, but the European Commission permits its use as an additive in juices, jams, dairy products and other foods. The involvement of this substance in the immune response and other biochemical processes such as the formation of collagen and the absorption of iron is well-known.

However, high levels of ascorbic acid can cause diarrhoea and gastrointestinal problems, as a result of which scientists are attempting to determine the content of vitamin C in foods with greater and greater accuracy.

Now, a group of researchers from the Faculty of Pharmacy of the USC has developed a new chromatographic technique (these are used to separate and identify chemical elements) aimed at accurately measuring the ascorbic acid in fruit juices and soft drinks. By applying this method, they have found that the amounts of vitamin C stipulated on the labels of many drinks are not real. In a sample of 17 fruit juices, soft drinks and isotonic drinks, only two correspond to what is indicated on the bottle.

Ana Rodríguez Bernaldo de Quirós is a member of the team which has developed the new technique, whose details have recently been published in the Food Chemistry magazine. "The other drinks contain much higher levels than those specified by the manufacturer because, as has already been indicated in a previous study, the label probably only shows the amount of added ascorbic acid, without taking into account the fruit's natural vitamin C content", she explained to SINC.

Bernaldo de Quirós highlights the greater resolution and sensitivity of the method, by means of which it is possible to detect up to 0.01 milligrams of vitamin C per litre, "thanks to the use of new column chromatography, based on spherical particles of ultra pure silica 3 microns in size".

"Another advantage of the method is its simplicity and speed, as the total time taken to carry out the analyses is no more than six minutes", the researcher remarked.

With the new technique, the valuation of the ascorbic acid in the drinks has revealed some curious data. Of the 17 samples analyzed, the one with the highest vitamin C content was an apple juice (840 mg/l), more than the orange juices (352-739 mg/l). The results for the pineapple and grape juices were 702 mg/l and between 30.2 and 261 mg/l for the soft drinks (orange, lemon and apple).

The researchers also evaluated how the vitamin C content of the orange juices and tea drinks varies while they are on the shelves in the temperature conditions specified by the manufacturer. After six days, the former barely lose 8% of their ascorbic acid while, in the tea drinks, this substance falls by 54% at 4ºC and practically disappears at room temperature.

References:

A. Rodríguez-Bernaldo de Quirós, M. Fernández-Arias, J. López-Hernández. "A screening method for the determination of ascorbic acid in fruit juices and soft drinks". Food Chemistry 116 (2): 509-512, 2009.

SINC | EurekAlert!
Further information:
http://www.plataformasinc.es

More articles from Health and Medicine:

nachricht The genes are not to blame
20.07.2018 | Technische Universität München

nachricht Targeting headaches and tumors with nano-submarines
20.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>