University of Ottawa NMR Facility Web Site

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Monday, December 11, 2017

NMR of Cranberries. Why Are They So Sour?

Arguably, one of the highlights of the Christmas season is a delicious turkey dinner.  The most common condiment for the turkey is a tart, mouth watering cranberry sauce.  Have you ever wondered why cranberries are so sour?  The sour taste comes from organic acids.  These can easily be detected in the 1H and 13C NMR spectra of cranberries.  The figure below shows the 1H and 13C NMR spectra of a D2O extract of crushed fresh cranberries.
Malic acid, citric acid, quinic acid and benzoic acid can easily be identified in the spectra.  These account for the sour taste.  Glucose, fructose and sucrose can also be identified however, the taste is dominated by the acids.  There are of course many other compounds present in cranberries at much lower concentrations than the acids and sugars.  Many of these account for the brilliant red color and antioxidant properties of this delicious healthy berry.  Enjoy your Christmas turkey accompanied by tasty, tart, cranberries!


John Anyam said...

Thanks for this post Sir. The HNMR was obtained via a PSYCHE experiment?

Glenn Facey said...

The 1H NMR spectrum in the BLOG post is a standard 1H spectrum with presaturation of water.

Anonymous said...

Thank you so much for sharing! It is so exciting to see fun applications of this analytical technique, especially as an undergraduate student who loves all things cranberry.