澳洲坚果叶茶的品质特征及挥发性成分分析

为了解澳洲坚果叶茶的品质特征及香气成分,以春季澳洲坚果一芽三叶为原料,依据炒青茶的制作方法加工成澳洲坚果叶茶,采用同时蒸馏萃取法结合GC-MS分析澳洲坚果叶茶的香气组成,同时结合感官审评和化学分析测定其品质。结果表明：澳洲坚果叶茶外形匀整饱满、滋味浓、口感厚重、香气浓醇、有特殊香气;化学成分分析表明其总灰分为(5.00±0.09)%、水浸出物为(39.00±0.27)%、多酚为(5.90±0.14)%,游离氨基酸(2.80±0.01)%,且不含咖啡碱,饮用品质良好。澳洲坚果叶茶的挥发性成分共鉴定出38种,根据化学结构差异可分为醛类13种,醇类6种,酮类6种,吡嗪类5种,酚类3种,脂肪酸类2种,烃类、吡咯类和呋喃类各1种,并以酚类、醇类、醛类、吡嗪类为主,相对含量分别为36.86%、20.98%、18.35%和14.46%;2°,4,4°,-三甲氧基查耳酮（20.25%）、2,4-二叔丁基苯酚（11.88%）、顺-2-戊烯-1-醇（10.52%）、1-戊烯-3-醇（6.71%）、壬醛（6.64%）是澳洲坚果叶茶中含量最高的5种挥发性成分。特征香气成分分析表明,醇类、醛类、酮类、吡嗪类等可能对澳洲坚果叶茶香气品质构成产生重要影响,而无特殊香气的酚类等对澳洲坚果叶茶香气品质的贡献程度也有一定的研究价值。

Analysis of Quality Features and the Characteristic Volatile Compound of Macadamia Leaf Tea

In order to understand the quality and aroma components, the macadamia leaf tea was developed with one bud and three leaves using the method of roasted technology in spring. The tea quality and chemical constituents were detected by the sensory evaluation method and chemical detection respectively. The aroma components of the macadamia leaf tea were extracted by simultaneous distillation extraction (SDE) technique and analyzed by gas chromatography-mass spectrometry (GC-MS). After brewing, the ideotype was uniform and neat, the aroma was heavy and mellow with special aroma, the soup was deep yellow, bright, and tasty. According to the chemical analysis, the biochemical compounds of the macadamia leaf tea contained (5.00±0.09)% total ash, (39.00±0.27)% water extract, (5.90±0.14)% tea polyphonie and (2.80±0.01)% amino acid. In particular it had no caffeine in the tea which could cause nervous excitement. A total of 38 common volatile components were identified including 13 aldehydes, 6 alcohols, 6 ketones, 5 pyrazines, 3 phenols, 2 fatty acids, 1 hydrocarbons, 1 pyrrole and 1 furan. The content of phenols, alcohols, aldehydes and pyrazines was 36.86%, 20.98%, 18.35%, 14.46%, respectively. The main chemical components of the tea were 2°,4,4°-trimethoxychalcone (20.25%), 2, 4-di-tert-butylphenol (11.88%), cis-2-penten-1-ol (10.52%), 1-penten-3-ol (6.71%), nonanal (6.64%). The analysis of characteristic aroma components indicated that alcohols, aldehydes, ketones, pyrazines would be responsible for the aroma quality of the tea. The effects of phenols with no special smell contribution to aroma quality of the tea were also worth future research.