Prediction of suitable brewing cuppages of Dahongpao tea based on chemical composition, liquor colour and sensory quality in different brewing

Abstract

oolong tea is famous for its characteristic of durably brewing. to explore suitable brewing cuppages and the scientific methods to brew Oolong tea in multiple steeping process. Dahongpao tea (Zhengyan, Banyan and Zhouyan tea) is well known Oolong tea variety, brewed at 14 times and assessed its chemical composition, infusion colour and sensory quality in different brewing intervals. The results showed that Zhengyan tea (A3) had the best quality of steeping among the chosen tea. It could be brewed up to 10 cuppages with 80% sensory score. The chemical composition and tea infusion colour strength were higher in Zhengyan tea. Though, 70% caffeine leached within first three steeping. The Forest regression model revealed that the suitable brewing time ranges between 4 and 10 in the chosen Dahongpao tea variety. This study provides a scientific method and suitable steeping times for the drinking of different Dahongpao tea through dynamic analysis of quantity of chemical composition, infusion colour strength and sensory quality. Oolong tea is well-known traditional Chinese tea. Dahongpao dated more than 350 years, is a representative of Oolong tea planted in Wuyishan, Fujian Province, China 1. Oolong tea attracts both domestic and foreign consumers due to its quality and characteristic of durably brewing. Generally, Dahongpao tea are classified as Zhengyan (A1, A2, A3) Banyan (B1, B2, B3) and Zhouyan tea (C1, C2, C3) based on different growing environments. Zhengyan tea grows in Wuyishan Scenic Area along the Jiuqu river at high altitude, with lots of gravel in soil, which create good ventilation and moderate acidity of soil for its growing, resulting in excellent quality. Banyan tea is planted around Zhengyan tea region, on red soil with high acidity; moreover, the soil is mostly clay. Therefore, the quality of Banyan tea is not that good as Zhengyan tea. Zhouyan tea is distributed on hilly area with alluvial soil full of calcium, causing its quality not that good as Zhengyan and Banyan tea. Besides, the quality of tea infusion depends on the types and tea/water ration of tea, temperature of water, brewing duration and times 2-4. To realize the best consumption quality experience of tea, scientific brewing methods are the key after cultivation and processing, especially for Chinese famous tea. Consumers are generally told that Oolong tea is suitable for continuous brewing up to more than 7 cuppages. This assertion is highly subjected to consumers' discretion and has not been validated by any scientific research. Sensory evaluation technique helps to determine the brewing cuppages and quality of tea infusion by its flavor strength. The flavor of tea infusion is determined by its chemical composition such as amino acids, caffeine, polyphenols and catechins. Several groups of compounds including phenolic compounds, purine alkaloids, amino acids, carbohydrates, nucleotides, organic acids and ions potentially contribute to the taste of tea. Sweetness of tea is mainly attributed to amino acids, as well as simple sugars such ...

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