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投稿时间：2021-10-21
投稿时间：2021-10-21
中文摘要: 鲜叶是制茶的基本原料，为探究大叶种鲜叶原料的物化特性，以春季和秋季的勐库大叶种、勐海大叶种、凤庆大叶种等茶树的单芽、一芽一叶、一芽二叶、一芽三叶共4个不同嫩度的新梢为研究对象，通过物理和化学指标的测定，分析嫩度、品种、季节间鲜叶品质的差异，并运用偏最小二乘判别分析（partial least squares discriminant analysis，PLS-DA）研究不同等级鲜叶的关键差异性指标。结果表明，鲜叶成熟度越高，叶长、节间长、百芽重、含水率、粗纤维等值越高，咖啡碱、全氮量、质量系数越低；秋季的叶长、百芽重、含水率、氨基酸等值大于春季；不同品种相同嫩度鲜叶的叶长、叶宽、叶面积差异不显著（P＞0.05）；勐海大叶种鲜叶春季的百叶重、秋季的质量系数值均高于相同季节的其他品种；春季单芽、秋季一芽一叶的茶多酚质量分数较高，均值分别为21.36%、22.73%；一芽二叶的氨基酸质量分数较高，春季和秋季的均值分别为3.51%、4.44%；春季和秋季的4个嫩度可分别分为2类和3类，氨基酸、茶多酚、叶长等为对差异贡献度较大的指标。该研究为云南大叶种新稍的分级及标准化加工提供理论参考。
Abstract:Fresh leaves are the raw material for tea processing.This paper aims to compare the physicochemical properties of fresh leaves of large-leaf tea cultivars in Yunnan.The samples with four different tenderness grades，including single bud，one bud with one leaf，one bud with two leaves，and one bud with three leaves，were plucked from Mengku large-leaf cultivar，Menghai large-leaf cultivar，and Fengqing large-leaf cultivar in spring and autumn.The tea quality was compared among different tenderness grade，among different cultivars，and between seasons.Partial least squares discriminant analysis（PLS-DA）was performed to explore the key indicators distinguishing different grades of fresh leaves.The results showed that the samples with higher maturity had longer leaf，longer internode，higher hundred-fresh leaf weight，higher water content，higher crude fiber，lower caffeine，lower total nitrogen，and lower quality index.The leaf length，hundred-fresh leaf weight，water content，and amino acid content in autumn were higher than those in spring.For the samples with the same tenderness grade，the leaf length，leaf width，and leaf area showed no significant difference among different cultivars（P＞0.05）.Menghai large-leaf cultivar had higher hundred-fresh leaf weight in spring and higher quality index in autumn than other cultivars.The content of tea polyphenols was higher in the single bud samples collected in spring and one bud with one leaf samples collected in autumn，with the average values of 21.36%and 22.73%，respectively.The amino acid content was higher in the samples of one bud with two leaves，with the average values of 3.51%and 4.44%in spring and autumn，respectively.PLS-DA results showed that the four tenderness grades of the tea samples collected in spring and autumn could be distinguished into two and three classes，respectively.Amino acids，tea polyphenols，and leaf length were the key indicators contributing to the difference，which can serve as the characteristic components distinguishing the different grades of large-leaf tea cultivars in Yunnan.This study provides a theoretical reference for the classification and standardized processing of large-leaf tea cultivars in Yunnan.
文章编号：202222009 中图分类号： 文献标志码：
基金项目:中国农业科学院科技创新工程专项（CAAS-ASTIP-TRICAAS）；国家重点研发计划项目（2017YFD0400802）；国家茶叶产业技术体系红茶加工岗位（CARS-19）
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