Effects of brewing conditions on composition, antioxidant capacity, and sensory analysis of white tea infusion
學生姓名:
蔡尚文
指導教授:
劉修銘
學期:
110下
摘 要:
White tea is the least processed tea type. It involves only two processes termed withering and drying. The minimal process ensures that white tea retains high concentrations of the main compounds. Thus, white tea has many health benefits, such as anti-oxidative, anti15 inflammatory, and anti-cancer effects. These studies aimed to investigate the effect of different infusion conditions on the compounds, antioxidant capacity, and sensory analysis of white tea. Catechin, caffeine and free amino acids content were analysed by high performance liquid
chromatography (HPLC), ultra-high performance liquid chromatography (UPLC), and spectrophotometry. Results showed that the amount of catechin and caffeine increased with the increase of brewing temperature and time in the infusions. Theanine and free amino acids
varied depending on tea types. Anti-oxidant capacity was determined by ABTS method, FRAP method, and Folin-Ciocalteu method. These methods showed that the antioxidant capacity of white tea gradually increased with infusion time and water temperature. It was found that the
water temperature of 98 ℃ with brewing times of 7 to 15 min could enhance the extraction of compounds and obtain higher antioxidant capacity. Sensory analysis was calculated by dose26 over-threshold value (Dot values), catechin quality index, and bitten-astringent index. Bai Hao
Yin Zhen had the highest catechin quality index and bitten-astringent index. According to the results of composition analysis and sensory evaluation, the optimal infusion conditions for white tea were established at a water temperature of 98 ℃ and a brewing time of 7 min. Under
these conditions, a large amount of compounds with antioxidant capacity can be extracted into the tea brew while obtaining a pleasant mildly bitter-astringent brew with flowers and citrus notes. In conclusion, it is important to combine sensory with chemical data to obtain the best
sensorial quality and the optimal healthy properties in white tea infusions.
chromatography (HPLC), ultra-high performance liquid chromatography (UPLC), and spectrophotometry. Results showed that the amount of catechin and caffeine increased with the increase of brewing temperature and time in the infusions. Theanine and free amino acids
varied depending on tea types. Anti-oxidant capacity was determined by ABTS method, FRAP method, and Folin-Ciocalteu method. These methods showed that the antioxidant capacity of white tea gradually increased with infusion time and water temperature. It was found that the
water temperature of 98 ℃ with brewing times of 7 to 15 min could enhance the extraction of compounds and obtain higher antioxidant capacity. Sensory analysis was calculated by dose26 over-threshold value (Dot values), catechin quality index, and bitten-astringent index. Bai Hao
Yin Zhen had the highest catechin quality index and bitten-astringent index. According to the results of composition analysis and sensory evaluation, the optimal infusion conditions for white tea were established at a water temperature of 98 ℃ and a brewing time of 7 min. Under
these conditions, a large amount of compounds with antioxidant capacity can be extracted into the tea brew while obtaining a pleasant mildly bitter-astringent brew with flowers and citrus notes. In conclusion, it is important to combine sensory with chemical data to obtain the best
sensorial quality and the optimal healthy properties in white tea infusions.
20220323專題討論題目、大綱、摘要-11032063蔡尚文.pdf