Cultivar-Specific Chemical Profiles and Processing-Related Changes in Lushan Yunwu Green Tea

Area of Science:

• Agricultural Chemistry
• Food Chemistry
• Plant Biochemistry

Background:

• Lushan Yunwu green tea (LYGT) quality is influenced by cultivar and processing.
• Understanding metabolite dynamics is crucial for optimizing LYGT production and sensory attributes.

Purpose of the Study:

• To investigate the dynamic changes of non-volatile and volatile metabolites in LYGT across different cultivars and processing stages.
• To elucidate the chemical basis for cultivar-specific sensory traits in LYGT.

Main Methods:

• Analysis of five LYGT cultivars using targeted and untargeted metabolomics.
• Quantification of 28 non-volatile and 12 volatile differential metabolites.
• Assessment of metabolic shifts during key processing steps, particularly fixation.

Main Results:

• Significant cultivar-dependent variations in flavonoids, catechins, amino acids, and aroma compounds (alcohols, terpenoids) were observed in fresh leaves.
• The fixation stage induced the most pronounced metabolic changes, involving enzymatic, thermal, and oxidative transformations of non-volatile compounds.
• Volatile compounds decreased during fixation, reducing grassy notes and generating high-temperature aroma compounds.

Conclusions:

• Metabolite profiles in LYGT are significantly influenced by both genetic (cultivar) and environmental (processing) factors.
• Fixation is a critical processing step that dramatically alters the chemical composition and sensory profile of LYGT.
• These findings provide a chemical basis for understanding LYGT quality and offer guidance for cultivar selection and process optimization.