茶李间作对茶树生长及秋季绿茶品质的影响

Effects of tea-plum intercropping on growth of tea trees and the quality of autumn green tea

  • 摘要: 【目的】研究茶李间作对茶树生长和秋季绿茶品质的影响,为茶园间作李树的可行性判定和提高夏秋茶的利用率提供理论依据。【方法】以福选9号为试材,测定单作茶园和间作茶园的百芽重、百克芽数等生长指标,运用分光光度法、高效液相色谱法(HPLC)和气相色谱—质谱法(GC-MS)检测秋季绿茶茶多酚、游离氨基酸、儿茶素、黄酮、氨基酸组分和香气物质等主要品质成分。【结果】间作茶园的相对湿度、百芽重、游离氨基酸、水浸出物、茶氨酸、酪氨酸和组氨酸等指标均显著高于对照茶园(P<0.05,下同),百克芽数、茶多酚、黄酮和酯型儿茶素等指标均显著低于对照茶园。共鉴定出205种香气成分,包括醛类、酯类、醇类、烯烃类、芳烃类、酮类、烷烃类和杂环化合物等,其中酯类和烯烃类的相对含量最高。主成分分析和正交偏最小二乘判别分析(OPLS-DA)表明,对绿茶香气有花香贡献的水杨酸甲酯、芳樟醇、顺式芳樟醇吡喃氧化物、(Z)-3-己烯醇,以及有栗香贡献的(Z)-己酸-3-己烯酯、苯甲醛、己醛和苯乙醛的相对含量,均显著高于对照茶园。相关分析表明,茶多酚、黄酮和酯型儿茶素与涩味和苦味强度呈显著正相关,与鲜醇度和甜味强度呈显著负相关;水浸出物、茶氨酸和酪氨酸与鲜醇度和甜味强度呈显著正相关,与涩味和苦味强度呈显著负相关;水杨酸甲酯、芳樟醇、苯甲醛和己醛等23种香气物质均与栗香和花香呈正相关,与清香、青香呈显著负相关。【结论】茶园间作李树能增强茶树生长势,改善茶园小气候,降低秋季绿茶的苦涩味,提高鲜爽度、栗香和花香,整体感官品质得到明显改善,可为今后继续在川南茶区推广应用茶李间作模式提供参考。

     

    Abstract: 【Objective】The effects of intercropping of tea-plums on the growth of tea trees and the quality of autumn green tea were studied to provide theoretical basis for the feasibility of intercropping of plums in tea gardens and to improve the utilization rate of summer and autumn tea. 【Method】In this study, Fuxuan 9 was the test variety, the growth potential indexes of tea trees(such as weight of 100 buds and the number of bud per 100 g) in monoculture tea garden and intercropping tea garden were measured, and main chemical compositions contents of autumn green tea, such as tea polyphenols, free amino acids, catechins, flavonoids, amino acid components and aroma components were analyzed by spectrophotometry, high performance liquid chromatography(HPLC) and gas chromatography-mass spectrometer(GC-MS).【Result】The humidity, weight of 100 buds, and the contents of free amino acid, water extracts, tyrosine, histidine and theanine in tea-plum intercropping garden were significantly higher than that in control tea garden(P<0.05, the same below); while the number of bud number per 100 g, the contents of tea polyphenols, flavone, and ester type catechins in intercropping garden were significantly lower. A total of 205 aroma components were identified from all samples, including aldehydes, esters, alcohols, alkenes, aromatics, ketones, alkanes, and heterocyclic compounds, among them, esters and alkanes had the highest relative content. Principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA) showed that the relative contents of methyl salicylate, linalool and linalool oxide I(pyran),(Z)-3-hexen-1-ol, which contributed to floral aroma, as well as relative contents of(Z)-hexanoic acid 3-hexenyl ester, benz aldehyde, hexanal and benzeneacet aldehyde, which contributed to chestnut aroma of green tea, were significantly higher in intercropping garden. Correlation analysis showed that there was extremely significant positive correlation between polyphenols, flavone, ester type catechins with astringency and bitterness intensity, while had significant negative correlation with umami, mellow and sweetness taste. Water extract, theanine and tyrosine had a significant positive correlation with umami, mellow and sweetness taste, while significant negative correlation with astringency and bitterness intensity. Moreover, 23 aroma compounds, such as methyl salicylate, linalool, benz aldehyde and hexanal had a significant positive correlation with floral aroma and chestnut aroma, while significant negative correlation with fresh and grassy green. 【Conclusion】Intercropping plum in tea gardens enhances the growth potential of tea trees, improves the microclimate of tea gardens, reduces the bitterness taste of autumn green tea, improves freshness, chestnut aroma, and floral aroma, and greatly improves overall sensory quality. This provides a reference for further promoting and applying the tea-plum intercropping model in the southern Sichuan tea region.

     

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