Studies On The Processing Techniques Of Anhui Oolong Tea

Oolong tea, as one of the six types of tea, produces principally in Fujian, Guangdong and Taiwan. With the quality of natural floral or fruity aroma and thickly-mellow and infusion-enduring taste, Oolong tea is one of the favorite teas to consumers and has a good reputation at home and abroad.Anhui is a major tea producing province in China, in which the Keemun black tea and Tunxi green tea have a worldwide reputation in tea markets, and Huangshan Maofeng tea, Keemun black tea and Lu'an Guapian tea take up three seats in China Top Ten Tea. However, Anhui tea industry develops relative slowly since the opening of the tea market in 1980s. Comparing with other greatly-yield provinces, Anhui tea exhibits three notable limitations as low outputs, low units yields and single tea types. In order to enrich tea types and enhancing tea resource utilization to push Anhui tea development, several tea-producing regions in Anhui have tried to process oolong tea in recent years. However, the tea species for oolong tea manufacturing is special and the processing technique is complicated, the producers have not found out the optimal tea processing techniques to the tea materials produced in Anhui province. Those lead to the final oolong tea product with a relatively low quality. Based on this issue, this paper explore the optimal oolong tea processing techniques with the comprehensive understandings of the physical and chemical properties of the fresh tea leaves produced at Anhui province, with which the final oolong teas have similar quality to the popular oolong tea in tea market.In order to explore the optimal processing techniques for Anhui oolong tea, this paper executed the strategic studies in different seasons(spring, summer, autumn)on the follows:1) Withering degree of fresh tea leaves. In order to investigate the effects of withering degree of fresh tea leaves grown at different tea seasons on oolong tea quality, the same batch of fresh tea leaves was divided into four groups, in which three groups were sunshined to lose 5%, 10% and 15% of moisture content respectively, while one group without sunshing was as control. The results showed that the optimum withering degree was 10% loss of moisture content of fresh tea leaves harvested at both spring and fall tea season which led to the final tea quality is the best. Furthermore, the fresh tea leaves grown in summer with either 5% or 10% loss of moisture content were processed to oolong tea with a higher aroma while the final oolong tea from those with 5% loss of moisture content with a higher taste.2) Shaking degree of withered tea leaves. The effects of shaking (zuoqing) degree divided into light, moderate and heavy group at different tea seasons on oolong tea quality were investigated. The results showed that the oolong teas made from the moderate group in both spring and autumn tea season were the best at the sensory quality, which were further confirmed with chemical analysis on the total content of essential oil, the quantity of aromatic components and the content of water extracts. However, the final oolong tea from the heavy group in summer tea season had a high quality.3) Shaking times of withered tea leaves. The same batch fresh tea leaves at different tea seasons were divided three groups, which were shaken at uniform degree with two times, four times and six times respectively after moderate withering. The results showed that the treatment with six shaking in all three seasons had the best quality. In both spring and autumn tea season, the oolong tea quality was improved with the increase of shaking times. In summer tea season, the tea quality was slightly improved at taste with six shakings compared to those with four shakings.4) Shaping technologies. In the procedure of shaping processing, the two different technologies were investigated. The first one was directly canvas-wrapped rolling to fix shape and the second one was reciprocating parched in hot pan after several times of canvas-wrapped rolling. The results showed that the two technologies resulted in tea products with similar quality in shape, color, aroma, and taste. However, the second one can reduce the labor intensity and improve the production efficiency.5) Compatibility of tea varieties. Three tea varities Camellia sinensis var. jiguanyin, Camellia sinensis var. tieguanyin and Camellia sinensis var. chuyezhong were investigated on the oolong tea manufacturing compatibility. Compared with oolong teas from the first two tea varieties, those processed from the tea leaves of Camellia sinensis var. chuyezhong had a representative sensory quality of oolong tea, but the aroma and the taste was thinner.The investigation results indicated that the fresh tea leaves of Anhui province which adopted properly processing techniques,with the final oolong teas have similar quality to the popular oolong tea in tea market.