Department of Chemistry, Tufts University, Medford, MA 02155, USA; Tufts University Sensory and Science Center, Medford, MA 02155, USA.
Department of Chemistry, Tufts University, Medford, MA 02155, USA.
Food Chem. 2018 Oct 30;264:334-341. doi: 10.1016/j.foodchem.2018.05.040. Epub 2018 May 7.
Climate effects on crop quality at the molecular level are not well-understood. Gas and liquid chromatography-mass spectrometry were used to measure changes of hundreds of compounds in tea at different elevations in Yunnan Province, China. Some increased in concentration while others decreased by 100's of percent. Orthogonal projection to latent structures-discriminant analysis revealed compounds exhibiting analgesic, antianxiety, antibacterial, anticancer, antidepressant, antifungal, anti-inflammatory, antioxidant, anti-stress, and cardioprotective properties statistically (p = 0.003) differentiated high from low elevation tea. Also, sweet, floral, honey-like notes were higher in concentration in the former while the latter displayed grassy, hay-like aroma. In addition, multivariate analysis of variance showed low elevation tea had statistically (p = 0.0062) higher concentrations of caffeine, epicatechin gallate, gallocatechin, and catechin; all bitter compounds. Although volatiles represent a small fraction of the total mass, this is the first comprehensive report illustrating how normal variations in temperature, 5 °C, due to elevational effects impact tea quality.
目前人们对气候如何在分子水平上影响作物品质还知之甚少。本研究采用气相色谱-质谱联用仪和液相色谱-质谱联用仪分析了中国云南省不同海拔高度茶叶中数百种化合物的变化。一些化合物的浓度增加了，而另一些则减少了百分之一百多。正交投影判别分析显示，具有镇痛、抗焦虑、抗菌、抗癌、抗抑郁、抗真菌、抗炎、抗氧化、抗应激和心脏保护作用的化合物在统计学上（p=0.003）可以区分高海拔和低海拔茶叶。此外，前者的甜、花香、蜂蜜味浓度更高，而后者则具有草味、干草味。此外，方差分析表明，低海拔茶叶中咖啡因、表儿茶素没食子酸酯、没食子儿茶素和儿茶素的浓度在统计学上（p=0.0062）更高；所有这些都是苦的化合物。尽管挥发物仅占总质量的一小部分，但这是首次全面报告表明，由于海拔高度的影响，温度正常变化 5°C 如何影响茶叶品质。
