市售普洱熟茶与绿茶、红茶咖啡碱质量分数的测定与比较  

Determination and Comparison of Caffeine Mass Fraction in Post-fermented Pu-erh Tea,Black Tea and Green Tea

作　　者：马燕[1] 张冬莲[1] 李家华[1] 袁文侠[1] 赵明[1] 

机构地区：[1]云南农业大学龙润普洱茶学院,云南昆明650201

出　　处：《云南农业大学学报（自然科学版）》2013年第5期745-749,共5页Journal of Yunnan Agricultural University:Natural Science

基　　金：云南自然科学基金项目(2010ZC084);国家自然科学基金项目(31160174)

摘　　要：咖啡碱是茶叶主要的生物碱，具有兴奋神经中枢作用，普洱熟茶具有茶性温和、兴旮『生低的特点，因此有假说认为普洱熟茶咖啡碱质量分数低于其他茶类。本文应用HPLC方法分别测定了绿茶（n=17）、红茶（n=7）和贮藏时间1～10年的普洱熟茶（n=56）样品的咖啡碱质量分数。结果显示，普洱熟茶咖啡碱质量分数为25．28～36．68mg／g，平均质量分数（31．76±2．85）mg／g；绿茶咖啡碱质量分数为23．95～38．33mg／g，平均质量分数（31．48±4．40）mg／g；红茶咖啡碱质量分数为30．43—36．93H影g，平均质量分数（33．89±2．54）mg／g。红茶咖啡碱质量分数显著高于绿茶和普洱茶（P〈0．05），普洱熟茶与绿茶咖啡碱质量分数差异不显著（P〉O05）。不同贮藏时间（1～10年）的普洱熟茶咖啡碱质量分数差异不显著（P〉0．05），提示贮藏过程普洱熟茶咖啡碱变化不大。以上结果表明普洱熟茶的咖啡碱质量分数不低，提示其兴旮陛低可能存在其他机制，需要进一步研究。Caffeine acts as a central nervous system stimulant and is the major alkaloid in tea plant. It plays key role for the alertness of tea. It was reported that post-fermented pu-erh tea has less alerted effects and possible contain lower caffeine. In this work, levels of caffeine in 80 samples including post fermented pu-erh teas storing 1 -10 years （n =56）, green teas （n = 17）, and black tea （n =7） were measured using HPLC. The mass fractions of caffeine in post-fermented pu-erh, green tea, and black tea were 24. 5 -38. 1 rag/g, 23.9 -39. 5 mg/g, and 30. 2 -37.5 rag/g, respectively. The mean of caffeine mass fraction was （31.76 ±2. 85） rag/g, （31.48± 4. 40） mg/g, and （33.89 ± 2. 54） mg/g, respec- tively. Statistical analysis showed that the caffeine mass fraction in black tea was higher than that in green and post-fermented pu-erh tea （P 〈 0. 05 ） ; and there were no significantly difference between caf- feine mass fractions in green and post-fermented pu-erh tea, and among pu-erh tea with different storing years. This work demonstrated that the level of caffeine in post-fermented pu-erh tea was not low, and suggested that the mechanism of decrease of alertness in post-fermented pu-erh tea need further research.

关 键 词：咖啡碱 测定 红茶 绿茶 普洱熟茶 

分 类 号：R151.3[医药卫生—营养与食品卫生学]