Ultra-high performance liquid chromatography used to measure tannins in wines

Development of rapid analytical method using chromatography and spectrometry to determine procyanidin concentration in both red and white wines

A novel method using ultra-high performance liquid chromatography (UHPLC) coupled with quadrupole time-of-flight (Q-TOF) mass spectrometry (MS) has been developed to validate rapid and reliable quantification of certain types of tannins in wines.

Tannins occur frequently in many plant-derived foods and drinks such as tea, many nuts and nut oils, grapes and wine, onion, apple, tomato, whisky and chocolate. Condensed tannins, also known as proanthocyanidins, are extensively studied for their interaction with other polyphenols.

In 2015, a subfamily of proanthocyanidins was reported and named crown procyanidins. They appeared to be more resistant to oxidation in wine than regular condensed tannins. Quantity of crown procyanidins in grape skin is determined by grape variety.

Relationship established between moderate wine consumption and improved cardiovascular health

Analysis made of urinary tartaric acid as a biomarker for wine through use of liquid chromatography and mass spectrometry According to a study, published in the European Heart Journal, ligh... Read More

Researchers at the University of Bordeaux, Villenave d'Ornon, France, set out to use experimental assays for the authentication of the liquid chromatographic method were carried out using commercially available red and white wines.

Sample red and white wines were sourced from grapes collected at technical maturity by the Institute of Vine and Wine Sciences at the University of Bordeaux.

Prior to UHPLC-Q-TOF injection, red wines were diluted 20 times and white wines were diluted 10 times in water and were filtered through a 0.45 µm filter. The validation of the analytical method was carried out by assessing the following parameters:

• matrix effect
• linearity
• accuracy
• repeatability
• intermediate reproducibility
• limits of detection
• limits of quantification.

The authors reported that their validation method, which followed international standards, demonstrated high sensitivity (LOQ = 0.033 mg/L), accuracy (recovery = 88.21% to 107.64%), repeatability (RSD = 1.99% to 11.03%), and intermediate reproducibility (RSD = 2.51% to 19.05%).

Minimal matrix effects were observed, ensuring the reliable and precise quantification across both wine types. The applicability of the method was confirmed through the successful analysis of wine samples, leading to the first quantification of crown procyanidins in white wine. Concentrations ranged from 0.81 mg/L to 15.88 mg/L in the different analysed wines.

This validated method provides a valuable tool for the study of crown procyanidin profiles in various wine matrices and establishes a foundation for future research into the role of crown procyanidins in wines and other food and beverage matrices where these compounds may be present.

Furthermore, the authors wrote that future research could expand on this methodology to other food and beverage matrices where crown procyanidins might be present.

Further reading:

Evolution of the crown procyanidins’ tetramer during winemaking and aging of red wine

Advanced LC-IMS-MS protocol for holistic metabolite analysis in wine and grape samples

Crown procyanidin tetramer: a procyanidin with an unusual cyclic skeleton with a potent protective effect against amyloid-β-induced toxicity