Monitoring Changes in the Volatile Compounds of Tea Made from Summer Tea Leaves by GC-IMS and HS-SPME-GC-MS  
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1 State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China 12 College of Food Science and Technology, Nanchang University, Nanchang 330031, China 2  
[PERSON]  
1 State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China 12 College of Food Science and Technology, Nanchang University, Nanchang 330031, China 2  
[PERSON]  
1 State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China 13 Kylin (Shandong) Pharmaceutical Technology Co., Ltd., Jinan 250109, China 3  
[PERSON]  
1 State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China 12 College of Food Science and Technology, Nanchang University, Nanchang 330031, China 2  
[PERSON]  
1 State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China 14 Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China 4  
[PERSON]  
5 Riante Ltd., Nanchang 330100, China 5  
[PERSON]  
5 Riante Ltd., Nanchang 330100, China 5  
[PERSON]  
5 Riante Ltd., Nanchang 330100, China 5  
[PERSON]  
1 State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China 14 Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China 14 Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China 14 Sino-German Joint Research Institute, Nanchang University,  
through different manufacturing processes [4]. Two types of tea are widely available in the global market: nonfermented (green tea) and completely fermented (black tea) [5; 6]. Tea aroma is the soul of tea and is one of the key factors that attracts consumers. Volatile compounds occur in minute quantities in tea, accounting for only 0.01-0.05% of the total dry mass of tea. More than 600 kinds of these compounds, such as linalool and its oxides, geraniol, and \(\beta\)-ionone have been detected in tea products, contributing greatly to tea quality [7]. At present, the research on tea aroma is mainly focused on spring tea, and relatively little research has been done on summer tea [8]. Previous research shows that the summer tea was suitable to produce black or green tea with good flavor [1; 9]. However, these studies only used summer tea to make one type of tea and used one method to detect its aroma substances, so the utilization and detection results for summer tea are not comprehensive. GC-IMS is a detection technology that combines ion mobility spectroscopy and gas chromatography [10] and can analyze the test results quickly, simply, intuitively, and accurately. It has been widely used in many fields, such as food flavor analysis [11] and quality inspection [12]. GC-MS has also been widely used in the separation and identification of volatiles in food [13]. Head space-solid phase micro-extraction (HS-SPME) is a volatile extraction technology that is superior to traditional extraction methods and is efficient, fast, and solvent-free [14]. This method is commonly used to extract the volatile compounds of various types of foods, such as wine [15], meat products [16], and tea [17]; it shows good repeatability, sensitivity and selectivity. In recent years, GC-MS and GC-IMS are often used in tea flavor analysis [17; 18]. Therefore, GC-MS and GC-IMS can be used in analyzing changes in volatile compounds in tea made from summer fresh tea leaves (_castanopsis. sinensis_, cv. Fuliangzhong). Flavor compounds can be monitored through GC-MS and GC-IMS. The main purpose of the current study is to investigate the aroma profiles of black tea (BT) and green tea (GT) produced with summer tea leaves. By bridging flavor change with substances, we can promote the quality of summer tea towards spring tea. In the present study, the summer fresh tea leaves (_castanopsis. sinensis_, cv. Fuliangzhong) were made into black tea (BT) and green tea (GT).