The Effect of Temperature and Humidity on Yellow Tea Volatile Compounds during Yellowing Process

Area of Science:

• Food Science
• Agricultural Chemistry
• Sensory Science

Background:

• Yellowing is a crucial step in yellow tea production.
• Environmental factors like temperature and humidity critically influence the yellowing process and final tea aroma.
• Understanding volatile compound changes during yellowing is key to optimizing tea quality.

Purpose of the Study:

• To analyze the impact of different environmental conditions on volatile compounds during yellow tea yellowing.
• To identify key differential volatile compounds affected by varying temperature and humidity.
• To establish a theoretical foundation for enhancing yellow tea aroma through controlled processing.

Main Methods:

• Gas Chromatography-Mass Spectrometry (GC-MS) was employed to identify and quantify volatile compounds.
• Partial Least Squares Discriminant Analysis (PLS-DA) was used to determine differential compounds under various conditions.
• Comparative analysis of volatile compound profiles under specific temperature and humidity regimes (40°C/90% RH, 50°C/50% RH, 30°C/70% RH).

Main Results:

• A total of 75 volatile compounds were identified, with 42 designated as differential compounds.
• Hydrocarbons, ketones, aldehydes, and alcohols were among the significantly altered compound classes.
• Higher humidity (90%) at 40°C reduced hydrocarbons and increased aldehydes, while 50°C/50% RH favored 3-hexen-1-ol, correlating with sensory evaluation.

Conclusions:

• Environmental conditions during yellowing significantly alter the volatile aroma profile of yellow tea.
• Specific temperature and humidity combinations can be manipulated to modulate the formation of key aroma compounds.
• The findings provide a scientific basis for controlling the yellowing process to achieve desired sensory characteristics in yellow tea.