# Analysis of the Changes in Volatile Components During the Processing of Enshi Yulu Tea
## 1 Introduction  
Tea, processed from the tender shoots of tea plants (_Camellia sinensis_ (L) O. [PERSON]), is one of the most commonly consumed aromatic beverages, next to water, in the world. In China, tea production encompasses six distinct types, including green, black, oo-long, white, yellow, and dark teas. These classifications are based on their manufacturing processes and sensory attributes [1]. Green tea, an unfermented variety of tea, is widely renowned for its exquisite flavor and potential health benefits. The fixation process holds paramount importance in the production of green tea, as it involves subjecting fresh leaves to high-temperature treatment to inhibit enzyme activity [2]. The fundamental manufacturing processes of green tea encompass fixing, rolling, shaping, and drying [1]. In the realm of Chinese green tea, pan-frying is the predominant fixation method, while Japanese greenteas typically undergo steaming fixation [3]. Enshi Yulu tea, which dates back to the Tang Dynasty, distinguishes itself as the sole representative of Chinese green tea that employs steaming fixation. It has significantly different aroma components.  
The aroma of tea is important in quality assessment and exerts a direct influence on the tea's overall value. The findings of multiple studies have consistently demonstrated that tea aroma consists of two components: the inherent fragrance derived from fresh leaves and the aroma produced during processing [4]. Thus, the volatile compounds in teas are greatly influenced by the tea cultivar [5], production season [6], altitude [7], shading treatment [8], manuring [9], and processing method [10]. The aroma of Enshi Yulu tea has been the subject of scholarly research. [PERSON] et al. found that _cis_-3-hexenol _cis_-3-hexenyl caproate are some of the most prominent compounds in Enshi Yulu tea. Enshi Yulu tea's fragrance differs from pan-fried green teas [11]. In other studies, some aroma compounds, such as _cis_-3-hexenyl butyrate and _cis_-3-hexenyl caprylate, are also unique to this tea [12]. [PERSON] et al. found that the volatile compounds in steamed green tea differed significantly from those in pan-fried green tea. Compounds with higher relative contents in Enshi Yulu tea include linalool, nonaldehyde, limonene, phenylmethanol, and other compounds [3]. The aforementioned studies primarily focus on Enshi Yulu tea, with no consideration given to the changes in aroma compounds during the processing stage.  
Although many studies have demonstrated significant changes in the aroma composition of green tea during processing, particularly during the fixation and drying stages [13; 14; 15], these studies have focused on pan-fried as opposed to steamed green tea processing. Due to its special flavor, which differs from that of pan-fried green tea, Enshi Yulu tea has recently attracted the attention of tea consumers and researchers. Therefore, to remedy this deficiency, we use headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME/GC-MS) techniques to investigate changes in aroma components during the processing of Enshi Yulu tea. The results of our study provide novel insights into the formation mechanism of the qualities of steamed green tea.