普洱生茶贮藏过程中品质指标的规律变化分析

该研究选用贮藏时间在3～20年的18个普洱生茶茶样，通过感官审评和理化成分分析，探究贮藏过程中普洱生茶品质指标的规律变化。结果表明，随着贮藏时间增加，普洱生茶的汤色色泽逐渐加深，香气由清香转为陈香，滋味由醇厚转为醇和，叶底颜色变深变暗，贮藏10年及以上感官品质有所提升，但贮藏18年后，感官品质开始下降；水浸出物、咖啡碱、GC、C、CG的含量呈不规则变化，没食子酸含量逐渐增加，游离氨基酸、EGC、EC、EGCG、GCG、ECG的含量随着贮藏时间的增加呈下降趋势。对17个品质指标标准化后进行相关性分析、主成分分析和聚类分析，发现品质指标间存在显著相关性，通过系统聚类可将茶样分为5类，每间隔3～4年聚为一类，其中，A类综合得分最高，D类次之，E类最低，说明品质指标随着贮藏年份的增加呈现下降趋势，且在3～4年贮藏时间内保持稳定。该结果为深入研究普洱生茶贮藏过程中的品质变化提供依据。

Analysis of Changes in Quality Indicators during Storage of Raw Pu-Erh Tea

In this study, 18 raw Pu-erh tea samples with storage times of 3 to 20 years were selected to investigate the changes in quality indicators of raw Pu-erh tea during storage through sensory evaluation and physicochemical composition analysis. The results showed that with increasing storage time, the color of raw Pu-erh tea gradually deepened, while the fresh aroma transformed into an aged fragrance. Simultaneously, the flavor changed from mellow and rich to mellow and neutral, and the color of the leaf bottom turned darker. The sensory quality was seen to improve after storage for 10 years and above, but began to decline after 18 years of storage. The water extract components, caffeine, GC, C, and CG showed irregular changes, while the concentration of gallic acid gradually increased. The contents of free amino acids, EGC, EC, EGCG, GCG, and ECG showed a decreasing trend with increasing storage time. Seventeen quality indicators were standardized and the samples were subjected to correlation analysis, principal component analysis, and cluster analysis that revealed significant correlations among the quality indicators. The tea samples could be divided into five categories by systematic clustering and could be clustered into one category every 3~4 years. In particular, category A had the highest composite score, followed by category D, while category E had the lowest score. Although the quality indicators show a decreasing trend with the increase in number of storage years, they remained stable during 3~4 years of storage. The results provide a basis for an in-depth study on the quality changes of raw Pu-erh tea during storage.