Abstract: To explore the changes in chemical composition and physical properties of the upper leaves of flue-cured tobacco at different maturity stages and their impact on tobacco quality, Yunyan 87 upper leaves were used as the material. Through different maturity treatments (70%, 80%, 90%), chemical analysis and physical testing methods were employed to evaluate the patterns and correlations of changes in chemical composition and physical properties. The results showed that with the increase in maturity of the upper leaves, total sugars, reducing sugars, and other indicators initially increased and then decreased, while starch and total nitrogen gradually decreased. The potassium-chlorine ratio and nicotine gradually increased. Significant correlations were found between the chemical composition and physical properties, especially between total sugars, reducing sugars, and tensile strength, filling value, which showed positive correlations with correlation coefficients of 0.95, 0.90, 0.98, and 0.96, respectively. These were negatively correlated with softness and leaf thickness, with correlation coefficients of –0.91, –0.86, –0.90, and –0.80. In addition, the experiment revealed that under the treatment of 80% yellowing in the upper leaves of flue-cured tobacco, the chemical composition showed better coordination, and the physical properties were moderate.

Key words: flue-cured tobacco; maturity; chemical composition; physical properties; correlation

摘要： 为探究烤烟不同成熟度上部叶的化学成分和物理特性变化及其对烟叶质量的影响，以‘云烟87’成熟度70%、80%、90%上部叶为材料，通过化学分析和物理检测评估化学成分和物理特性的变化规律及其相关性。结果表明，随着上部烟叶成熟度提高，其总糖、还原糖含量等指标先增后降，而淀粉、总氮含量等逐渐降低，钾氯比、烟碱含量逐渐升高。化学成分及与物理特性间存在显著相关性，尤其是总糖、还原糖含量与拉力、填充值呈正相关，相关性系数分别达0.95、0.90，0.98、0.96；与柔软度值、叶厚呈负相关，相关系数分别为–0.91、–0.86、–0.90、–0.80。此外，烤烟上部叶片在综合变黄80%处理下，具有较好的化学成分协调性和适中的物理特性。

关键词: 烤烟；成熟度；化学成分；物理特性；相关性