Abstract:

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.

Key words: macadamia leaf tea, aroma components, GC-MS, sensory evaluation