Black tea aroma formation during the fermentation period

Area of Science:

• Food Chemistry
• Agricultural Science
• Sensory Science

Background:

• Black tea aroma is crucial for quality.
• Fermentation is a key step in black tea processing.
• Understanding volatile compound formation is essential.

Purpose of the Study:

• To systematically investigate black tea aroma formation during fermentation.
• To identify key volatile compounds and their precursors.
• To correlate volatile changes with sensory perception.

Main Methods:

• Identification of 158 volatile compounds using analytical techniques.
• Quantification of volatile compound classes: amino acid-derived volatiles (AADVs), carotenoid-derived volatiles (CDVs), fatty acid-derived volatiles (FADVs), and volatile terpenoids (VTs).
• Analysis of precursor degradation: fatty acids, amino acids, carotenoids, and glycosidically bound volatiles (GBVs).
• Sensory evaluation of aroma intensity (green, sweet, floral/fruity).

Main Results:

• Significant increases in AADVs and CDVs during fermentation.
• Diverse changes in FADVs and VTs.
• Degradation of precursors (fatty acids, amino acids, carotenoids, GBVs) to form aroma components.
• Decrease in green scent intensity; significant increase and dominance of sweet and floral/fruity scents.
• AADVs and CDVs contribute more to sweet/floral/fruity aromas than VTs.

Conclusions:

• Fermentation drives the formation of desirable sweet and floral/fruity aromas in black tea.
• AADVs and CDVs are key contributors to the characteristic black tea aroma profile.
• The study elucidates the biochemical pathways influencing black tea sensory quality.