Riddet Institute, Massey University, Palmerston North 4442, New Zealand.
Riddet Institute, Massey University, Palmerston North 4442, New Zealand.
Food Chem. 2014;152:546-51. doi: 10.1016/j.foodchem.2013.12.005. Epub 2013 Dec 8.
The effects of season and plantation on the polyphenol content of Camellia sinensis (tea) leaves were determined. Aqueous and organic extracts of freeze-dried fresh (unfermented) and black (fully-fermented) tea leaves were prepared for a structured set of samples (fermented and unfermented teas from six high-, mid- and low-grown plantations; fermented and unfermented teas from two harvesting seasons from four highland plantations), collected from the main tea-growing regions in Sri Lanka. Total catechin content and amounts of individual catechins, flavonols and theaflavins were determined by HPLC. Mean values for the phenolic constituents were generally significantly higher (p<0.05) with solvent extraction. The mean values for total catechins, total flavonols and caffeine in the aqueous extracts from unfermented teas were 10.6%, 1.5% and 2.9%, respectively. For both unfermented and fermented tea leaves, a significant (p<0.05) interaction between plantation and season was observed for phenolic constituents. Ferric reducing antioxidant power was positively (p<0.05) correlated with (-)-epicatechin gallate and total phenolic contents.
研究了季节和种植园对茶树（茶）叶中多酚含量的影响。为一组结构样品（来自 6 个高、中、低种植园的发酵和未发酵茶；来自 4 个高地种植园的两个收获季节的发酵和未发酵茶）制备了冻干新鲜（未发酵）和黑茶（完全发酵）茶叶的水提物和有机溶剂提取物。从斯里兰卡主要茶叶种植区收集。用 HPLC 测定总儿茶素含量和儿茶素、黄酮醇和茶黄素的含量。用溶剂提取时，酚类成分的平均值通常明显较高（p<0.05）。未发酵茶的水提取物中的总儿茶素、总黄酮醇和咖啡因的平均值分别为 10.6%、1.5%和 2.9%。对于未发酵和发酵的茶树叶，酚类成分的种植园和季节之间存在显著（p<0.05）的相互作用。铁还原抗氧化能力与（-）-表儿茶素没食子酸酯和总酚含量呈正相关（p<0.05）。
