Bioconversion of alpha-Damascone by Botrytis cinerea

Area of Science:

• * Microbiology and Organic Chemistry
• * Food Science and Technology
• * Natural Product Chemistry

Background:

• * Alpha-damascone is a key aroma compound found in fruits and fermented beverages.
• * Understanding its transformation is crucial for flavor development in food and beverages.
• * Grape must is a complex matrix where microbial and chemical reactions can occur.

Purpose of the Study:

• * To investigate the bioconversion of alpha-damascone by Botrytis cinerea strains.
• * To identify the biotransformation products formed under specific conditions.
• * To explore potential acid-catalyzed chemical transformations of alpha-damascone.

Main Methods:

• * Incubation of alpha-damascone with four Botrytis cinerea strains in grape must (pH 3.2).
• * Analysis of reaction products using High-Resolution Gas Chromatography (HRGC).
• * Utilized coupled HRGC techniques, including HRGC-Mass Spectrometry and HRGC-Fourier Transform Infrared Spectroscopy for identification.

Main Results:

• * Identified several biotransformation products: 3-oxo-alpha-damascone, cis- and trans-3-hydroxy-alpha-damascone, gamma-damascenone, 3-oxo-8,9-dihydro-alpha-damascone, and cis- and trans-3-hydroxy-8,9-dihydro-alpha-damascone.
• * Observed acid-catalyzed chemical transformation of alpha-damascone to diastereomers of 9-hydroxy-8,9-dihydro-alpha-damascone.
• * Confirmed product structures through advanced spectroscopic and chromatographic analyses.

Conclusions:

• * Botrytis cinerea effectively biotransforms alpha-damascone in grape must.
• * Both microbial and chemical pathways contribute to the diversity of damascone derivatives.
• * Advanced analytical techniques are essential for characterizing complex natural product transformations.