茶树2种酰基化黄酮苷的分布规律及加工变化特性研究

Distribution and processing characteristics of two acylated flavonol glycosides in Camellia sinensis

本研究从茶叶中分离纯化出2种酰基化黄酮四糖苷{quercetin-3-O-[(E)-p-coumaroyl-(1→2)][α-Larabinopyranosyl-(1→3)]-[β-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside,F_(1);kaempferol-3-O-[(E)-p-coumaroyl-(1→2)]-[α-L-arabinopyranosyl-(1→3)]-[β-D-glucopyranosyl-(1→3)-α-Lrhamnopyranosyl-(1→6)]-β-D-glucopyranoside,F_(2)},通过自主建立的高效液相色谱(high performance liquid chromatography,HPLC)定量检测方法,系统研究了F_(1)与F_(2)在茶树不同组织、叶位、品种中的分布特点,探究光照对F_(1)和F_(2)含量的影响,以及两者在乌龙茶加工过程中的动态变化。结果表明:F_(1)主要在叶和茎中分布,F_(2)仅存在于叶中;根中未检测到F_(1)与F_(2)。随着叶片成熟度的增加,F_(1)与F_(2)的含量呈先升高后降低的趋势。在42个茶树品种中,F_(1)和F_(2)含量范围分别为0~2.31、0~1.56mg/g;F_(1)在‘黄金菊’中含量最高,在‘本山’和‘绿芽佛手’中未检测到;F_(2)在‘黄金菊’中含量最高,在‘绿芽佛手’‘金面奇兰’‘中黄2号’和‘本山’中未检测到。对3个茶树品种进行遮阴实验,发现遮阴处理组F_(1)含量显著降低,说明光照对其形成具有重要作用。选取‘福建水仙’鲜叶进行乌龙茶加工,F_(1)和F_(2)含量在整个加工过程中呈降低趋势,且在杀青工序中降幅最大,做青工序中降幅最小,表明不同加工工序对两者的含量存在不同程度的影响。

In this study,two acylated flavonol tetraglycosides{quercetin-3-O-[(E)-p-coumaroyl-(1→2)][α-L-arabinopyranosyl-(1→3)]-[β-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside,F_(1);kaempferol-3-O-[(E)-p-coumaroyl-(1→2)]-[α-L-arabinopyranosyl-(1→3)]-[β-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside,F_(2)}were isolated and purified from Camellia sinensis,and the distribution characteristics of F_(1) and F_(2) in different tissues,leaf positions,and tea cultivars were systematically studied through the independent established high performance liquid chromatography(HPLC)method.The effect of light on the contents of F1 and F2,and the dynamic changes in the processing stages of oolong tea were also studied.The results showed that F1 was mainly distributed in tea leaves and stems,and F2 was only present in leaves;neither F1 nor F2 was detected in the roots.With the increase of leaf maturity,the contents of F1 and F2 firstly increased and then decreased.Among the 42 tea cultivars,the contents of F1 and F2 ranged from 0-2.31 mg/g and 0-1.56 mg/g,respectively.F1 had the highest content in‘Huangjinju’and was not detected in‘Benshan’and‘Lüyafoshou’tea cultivars.F2 had the highest content in‘Huangjinju’and was not detected in‘Lüyafoshou’,‘Jinmian Qilan’,‘Zhonghuang No.2’and‘Benshan’.Shading experiments were carried out on three tea cultivars,and it was found that the content of F1 in the shading treatment group was significantly reduced,indicating that the light plays a significant role in the formation of F1.The fresh leaves of‘Fujian Shuixian’were selected for the processing of oolong tea.The contents of F1 and F2 showed downward trends during the whole processing stages,and the largest decline was observed in the process of fixation,while the smallest was in the process of rotation,which shows that different processing operations have different degrees of influences on the contents of two substances.