节点文献
代谢组学解析遮阴对茶叶主要品质成分的影响
Effects of Shading on Main Quality Components in Tea(Camellia Sinensis(L) O. Kuntze) Leaves Based on Metabolomics Analysis
【摘要】 【目的】茶叶生产上常采用遮阴处理来提高其品质,然而,黑暗遮阴对茶叶品质的影响尚未清楚。本文重点研究黑暗遮阴对茶叶中主要品质成分的影响,以期更加详细了解遮阴与茶叶品质的关系。【方法】利用遮阳网对茶树进行中度(65.0%)、黑暗(99.7%)两个遮阴处理,不遮阴作为对照;采用紫外分光光度法检测总多酚、总氨基酸、总黄酮的含量,同时采用超高效液相色谱-四级杆-飞行时间质谱(UHPLC-Q-TOF/MS)对茶叶中的主要品质成分进行详细调查。【结果】与对照相比,中度遮阴显著降低了茶叶的总氨基酸、总黄酮含量(P<0.05),轻微降低了总多酚含量,增加了酚氨比;黑暗遮阴显著降低了总氨基酸和总黄酮含量,显著增加了总多酚含量和酚氨比(P<0.05)。主成分分析(PCA)表明,两个遮阴处理明显改变了茶树叶片的代谢组。进一步鉴定得到了87个化合物,包括2个生物碱、18个氨基酸、12个儿茶素类、8个儿茶素二聚体类、19个黄酮(醇)糖苷、5个香气糖苷、6个核苷(酸)、9个酚酸、8个其他化合物;与对照相比,82个化合物在遮阴处理后出现显著差异(P<0.05)。遮阴后,生物碱含量显著增加;氨基酸呈现多样性变化,半数以上氨基酸含量显著下降;部分儿茶素类及二聚儿茶素类物质的含量在中度遮阴后显著降低,然而大部分儿茶素类和儿茶二聚体素类物质的含量却在黑暗遮阴后显著上升;绝大部分黄酮(醇)糖苷的含量在遮阴后出现显著下降,且遮阴程度越高,下降越多;大部分香气糖苷含量在遮阴后显著上升;大部分核苷(酸)含量在遮阴后显著降低;多数酚酸的含量在遮阴后显著上升。【结论】黑暗遮阴后,生物碱、儿茶素类及儿茶素二聚体类等物质含量显著上升,氨基酸含量显著下降,酚氨比显著上升,预示黑暗遮阴处理可能不利于提高茶叶的品质。
【Abstract】 【Objective】Shading treatment is widely used to improve the quality of teas in tea yielding. However, the effects of dark shading on the quality of teas remain unclear. This study focused on the effects of dark shading on the main quality components in teas to understand the relationship between shading and tea quality in detail.【Method】Moderate(65.0%) and dark(99.7%) shading treatments were applied to tea plants by using black shading net, with non-shading as control. Ultraviolet spectrophotometry was employed to determine the contents of total polyphenols, total amino acids and total flavonoids, and ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UHPLC-Q-TOF/MS) was employed to investigate the quality components in tea leaves.【Result】Compared with the control group, moderate shading treatment significantly reduced the contents of total amino acids and total flavonoids(P<0.05), and slightly reduced the content of total polyphenols, and therefore increased the ratio of polyphenols to amino acids. Dark shading treatment significantly reduced the contents of total amino acids and total flavonoids, while significantly increased the contents of total polyphenols and the ratio of phenol to ammonia(P<0.05). Principal component analysis showed that the two shading treatments significantly changed the metabolite pattern in tea leaves. A total of 87 compounds were identified, including 2 alkaloids, 18 amino acids, 12 catechins, 8 dimeric catechins, 19 flavone glycosides and flavonol glycosides, 5 glycosidically bound volatiles(GBVs), 6 nucleosides and nucleotides, 9 phenolic acids, and 8 other compounds. The contents of 82 compounds in two shading groups showed significant differences comparing with the control(P<0.05). After shading, the contents of alkaloids significantly increased; amino acids showed various change trends, with the contents of more than half of amino acids significantly decreased. The contents of several catechins and dimeric catechins significantly decreased in moderate shading group, while the contents of most catechins and their dimers significantly increased in dark shading group. The content of most flavone glycosides and flavonol glycosides showed decreased trend along with the increase of shading degree. The contents of most GBVs significantly increased. The contents of most of nucleosides and nucleotides significantly decreased; the content of most phenolic acids significantly increased.【Conclusion】After dark shading treatment, the contents of alkaloids, catechins and dimeric catechins significantly increased, while the contents of amino acids significantly decreased, and therefore the ratio of phenol to ammonia significantly increased, which indicated that dark shading might not contribute to improve the tea quality.
【Key words】 tea; shading; metabolomics; LC-MS; secondary metabolism;
- 【文献出处】 中国农业科学 ,Scientia Agricultura Sinica , 编辑部邮箱 ,2019年06期
- 【分类号】S571.1
- 【被引频次】17
- 【下载频次】822