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Characterization of the changes of aroma profiles in large-leaf yellow tea during processing using GC–MS and electronic nose analysis

Summary

This study examined how large-leaf yellow tea develops its distinctive fried rice-like aroma during processing. Researchers identified 178 different volatile compounds throughout eight processing stages using advanced analytical techniques. The full fire roasting step was found to be most important for creating the final roasted and nutty flavors, generating 30 new nitrogen-containing compounds. An electronic nose device successfully tracked these aroma changes in real-time, suggesting it could be used for quality control in tea production.

Background

Large-leaf yellow tea (LYT) is valued for its health benefits and characteristic fried rice-like odor. Tea processing is crucial for aroma formation, involving fixing, rolling, yellowing, roasting, and full fire processing stages. The volatile compounds and their changes during LYT processing have not been comprehensively studied.

Objective

To characterize volatile profiles and aroma properties of LYT throughout processing using GC–MS and electronic nose (E-nose) technology. The study aims to reveal how different processing steps affect volatile compound composition and to evaluate E-nose suitability for real-time aroma monitoring during tea production.

Results

178 volatile compounds were identified across eight processing stages, with alcohols dominating before full fire processing and heterocyclic compounds becoming prominent afterward. Full fire processing generated 30 N-containing compounds newly. E-nose successfully distinguished tea samples at different processing stages with principal component analysis showing 96.3% cumulative contribution. Key aroma compounds differed from other yellow tea types.

Conclusion

Full fire processing is crucial for final aroma formation of LYT, promoting heterocyclic compound formation and roasted/nutty flavors. E-nose technology is suitable for non-destructive, real-time detection and monitoring of volatile changes during tea production, providing practical quality control applications. The aroma profiles of LYT are distinct from other yellow teas due to unique critical processing procedures.
  • Published in:Food Chemistry X,
  • Study Type:Analytical Study,
  • Source: PMID: 40463654, DOI: 10.1016/j.fochx.2025.102507
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