Have you ever wondered where the ruby colour of red wine comes from? And did you know that some wine producers enhance the colour of wine even though they shouldn't? These questions arose during research conducted by scientists from the eastern town of Olomouc, which focuses on natural dyes called anthocyanins.
Petr Bednar from the Department of Analytical Chemistry of Palacky University in Olomouc.
"Our research is focused on the analysis of chemical changes of various compounds during their interaction with a cell or during their passing through a human body. Among others, we study the behaviour of anthocyanin dyes belonging to the group of natural polyphenolic compounds. We are interested in the sources of these anthocyanins. The analysis of the content of anthocyanins provides interesting information about the character of the source."
What are anthocyanins and where can they be found?
"These dyes can be found mainly in coloured fruits, like wine grapes, different kinds of berries, flowers, some leaves and so on. These compounds have some important functions in the nature, include prevention of plant tissue from UV radiation, attraction of insects for pollination or orientation of animals for finding of food. Anthocyanins occur also in different kinds of food, including wine and then the study of anthocyanin profile gives important information for differentiation of the food product, information about authenticity, or even point out to some prohibited treatment of the food."
Do these plant pigments have any beneficial effects for human health?
"Several effects have been described up to now, including strong anti-oxidant and anti-microbial activity, preventing cancer and cardiovascular disorders. Recently also some anti-diabetic effects were described in the related scientific articles."
Can you detect whether the colour of red wine has been enhanced by added colorants? And what kind of colouring agents are they typically?
"Our methods are able to detect additional coloration using synthetic dyes or natural dyes which are not authentic. Anthocyanins present in berries are structurally similar but not identical with those contained in wine grapes. The presence in non-authentic anthocyanins in wine suggests that the wine was artificially coloured. Our methods, which are based on a combination of liquid chromatography with mass spectrometry are able to distinguish the individual anthocyanins."
Could your expertise be potentially used to expose winemakers who adulterate wine?
"The proposed method was tested up to now, I would say, only in academic environment, or better said in university laboratory. Its using in routine control is connected with the creation of standardised university laboratories, or better said normed methods which represents a relatively long time, many confirmation experiments as well as appropriate funding. However, apart from the discussed method, the experiments are very useful for complex characterisation of different kinds of food products."
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