Variations in Fatty Acids Affected Their Derivative Volatiles during Tieguanyin Tea Processing

Area of Science:

• Food Chemistry
• Agricultural Science
• Plant Biochemistry

Background:

• Fatty acids (FAs) are crucial precursors to volatile aroma compounds in oolong tea.
• The precise relationship between FAs and their derivatives during oolong tea production is not well understood.
• Key aroma components in oolong tea are derived from fatty acids.

Purpose of the Study:

• To investigate the transformation of fatty acids and their derivatives during oolong tea manufacture.
• To clarify the relationship between fatty acids and fatty acid-derived volatiles (FADV) during oolong tea processing.
• To explore methods for improving oolong tea aroma quality through fatty acid manipulation.

Main Methods:

• Tieguanyin tea leaves were processed into oolong tea and green tea (control).
• Fatty acids were extracted using the sulfuric acid-methanol method.
• Fatty acid-derived volatiles (FADV) were extracted using solvent-assisted flavor evaporation (SAFE).

Main Results:

• Unsaturated fatty acids were more abundant than saturated fatty acids and decreased significantly during tea processing.
• Fatty acid content showed greater variation in oolong tea compared to green tea, particularly during the withering stage.
• Fatty acid-derived volatile content initially increased then decreased, showing a significant negative correlation with total fatty acids during oolong tea manufacture.
• Methyl jasmonate (MeJA) content was significantly and negatively correlated with most fatty acids during the green tea processing stage.

Conclusions:

• Fatty acid levels decrease, while their volatile derivatives fluctuate dynamically during oolong tea production.
• A significant negative correlation exists between fatty acids and their derivatives, suggesting a transformation process.
• Targeted manipulation of fatty acid transformation pathways offers a promising strategy for enhancing the aroma profile of oolong tea.