Investigation on the volatiles and aromatic characteristic of Raw Pu-erh tea with different storage durations by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry and odor activity value analysis

Abstract

Abstract Volatile constituents are critical to the flavor of tea, but the changes of them in Raw Pu-erh tea (RAPT) during storage have not been clearly understood. This work aimed to investigate the volatile composition and their changes of RAPT at various storage durations. The volatile profile of RAPT was determined using headspace solid-phase microextraction in combination gas chromatography-mass spectrometry. A total of 130 volatile compounds were identified in RAPT samples, and 64 of them were shared by all samples. The aroma attributes of RAPT over a storage period ranging from 0 to 10 years were assessed through the integration of odor activity value, aroma characteristic influence value and multivariate statistical. The results revealed that RAPT highlighted a distinct floral and fruity aroma profile after storage for approximately 3 - 4 years. Furthermore, a notable shift in aroma was observed after 5 and 10 years of storage. According to the odor activity value (≥ 100), eight volatile compounds were revealed as the key compounds to the aroma of RAPT during storage. These compounds include linalool, α-terpineol, geraniol, trans-𝛽-ionone, α-ionone, (E,E)-2,4-heptadienal, 1-octanol, and octanal. The findings of this study offer a scientific foundation and valuable insights for understanding the quality of RAPT during storage.