Oolong tea made from tea plants from different locations in Yunnan and Fujian, China showed similar aroma but different taste characteristics

Abstract

Consistent aroma characteristics are important for tea products. However, understanding the formation of tea aroma flavor and correspondingly proposing applicable protocols to control tea quality and consistency remain major challenges. Oolong tea is one of the most popular teas with a distinct flavor. Generally, oolong tea is processed with the leaves of tea trees belonging to different subspecies and grown in significantly different regions. In this study, Yunnan and Fujian oolong teas, green tea, black tea, and Pu-erh tea were collected from major tea estates across China. Their sensory evaluation, main water-soluble and volatile compounds were identified and measured. The sensory evaluation, total polysaccharide, caffeine, and catechin content of Yunnan oolong tea was found to be different from that of Fujian oolong tea, a result suggesting that the kinds of tea leaves used in Yunnan and Fujian oolong teas were naturally different. However, according to their aroma compounds, principal component analysis (PCA) and cluster analysis (CA) of the volatile compounds showed that the two types of oolong teas were similar and cannot be clearly distinguished from each other; they are also different from green, black, and Pu-erh teas, a result indicating that the same oolong tea processing technology applied to different tea leaves results in consistent aroma characteristics. The PCA analysis results also indicated that benzylalcohol, indole, safranal, linalool oxides, β-ionone, and hexadecanoic acid methyl ester highly contributed to the distinct aroma of oolong tea compared with the other three types of teas. This study proved that the use of the same processing technology on two kinds of tea leaves resulted in a highly consistent tea aroma.

Effects of roasting treatment on non‐volatile compounds and taste of green tea

“…Moreover, soluble sugar also increases due to macromolecular substances, such as starch and others hydrolysis to glucose, fructose, sucrose. (Wang et al, 2016). Note that the decrease in catechins and bitter amino acids could effectively reduce the astringency and bitterness of green tea, while the increase in total soluble sugars and sweet amino acids could balance the flavour of tea infusion.…”

“…A great number of studies reported that the tea polyphenols, amino acids, soluble sugars and chlorophyll contents decreased in roasting process. Meanwhile, amino acids and soluble sugars involved in Maillard reaction, which formed many roasted flavour compounds and effectively improved the sensory quality of tea (Wan et al, 2000;Wang et al, 2016). Recently, there has been an increase on the study of oolong tea, and most researches focused on the effects of roasting on the aroma of tea.…”

Characterization of Volatile Components of Eight FengHuang Dancong Manufactured Teas and Fresh Leaves by HS-SPME Coupled with GC-MS

“…Saturated hydrocarbons usually make a minor contribution to the tea aroma, whereas unsaturated hydrocarbons are important contributors to the tea aroma [23]. D-limonene is considered an important volatile and is described as having a "lemon-like" aroma.…”

Correlation analysis between filamentous fungi and chemical compositions in a pu‐erh type tea after a long‐term storage

“…Water‐soluble sugar (WSS) content was determined by visible spectrophotometer method with anthraquinone on 620 nm (Liang et al, 2005). Contents of GA and catechins, including C, EC, EGC, ECG, and EGCG, were determined by HPLC using an Agilent 1200 Series system with Agilent C 18 Chromatogram column (250 mm × 4.6 mm, 5 μm) (Wang et al, 2016). Caffeine content was determined by Agilent 1200 HPLC equipment using Agilent C 18 Chromatogram column (250 mm × 4.6 mm, 5 μm) with solvent A (100% acetonitrile) and solvent B (0.2% v/v acetic acid–water solution) as mobile phase (Tan et al, 2012).…”