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Wine bottles and glasses.

Doctoral defence of Yanning Dou, MSc, 21.11.2023: Alcoholic beverages are not just ethanol and water, but chemically extremely complex mixtures

The doctoral dissertation in the field of Chemistry will be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus.

What is the topic of your doctoral research? Why is it important to study the topic?

Molecular level characterization of different alcoholic beverages with high-resolution mass spectrometry. These beverages include Finnish berry wines, gins from different origins, and Chinese baijius. Alcoholic beverages are both culturally and commercially highly valued products. The properties of the alcoholic beverages can be attributed to their complex chemical compositions. By using high-resolution mass spectrometry, we have widened our knowledge on the rich chemistry of alcoholic beverages consumed worldwide.

What are the key findings or observations of your doctoral research?

This study has shown the vast molecular level complexity of the alcoholic beverages. Hundreds of compounds were detected from the samples. Several dozens of compounds were tentatively identified from each type of beverage. Matured or flavored beverages are not just ethanol and water, but chemically extremely complex mixtures having large number of compounds present in minor amounts. These compounds create the sensatory properties (for example color, taste, and aroma) of the beverage in question.

How can the results of your doctoral research be utilised in practice?

Understanding of the chemical composition of an alcoholic beverage helps to develop its maturation process as well as fine-tuning its desired aroma profile. In addition, it helps to design new types of products and enables the identification of the possible counterfeit products.

What are the key research methods and materials used in your doctoral research?

Solid phase extraction of the phenolic compounds from berry wines followed by spectrophotometric determination of the total phenolic contents. Direct inlet mass spectrometric analysis of alcoholic beverages chemical compositions by ultrahigh-resolution FT-ICR mass spectrometry, which is a unique technique in Finland.

The doctoral dissertation of Yanning Dou, MSc, entitled Chemical Fingerprinting of Alcoholic Beverages Using Ultrahigh-Resolution Mass Spectrometry will be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus. The opponent will be Professor Carlos Cordeiro, University of Lisbon, Portugal, and the custos will be Professor Janne Jänis, University of Eastern Finland. Language of the public defence is English.