常规化学指标结合卡方概率密度函数的烟叶质量评价模型构建与应用

Development and application of tobacco quality evaluation model by combining routine chemical indexes with Chi-square probability density function

为了更加科学、系统、高效地实现烟叶相对精准、快速的分级,以还原糖总氮比(Kovalenko指数)、总氮烟碱比和烟碱质量分数作为烟叶质量的主要评价指标,基于具有非线性、非单调、非对称特点的卡方函数,以及不同外观和感官质量等级的复烤模块化学指标的分布规律,建立了针对云南产区烟叶内在质量的评价模型。基于建立的评价模型和近红外光谱检测数据,对红塔集团不同复烤模块烟叶的内在质量进行评价。结果表明:①质量评价结果与烟叶外观以及感官质量分类的趋势高度相关。②将化学指标优劣互补(例如,烟碱质量分数高的上部烟和烟碱质量分数低的下部烟)且感官评价分数较低的烟叶以一定比例均匀混合之后评价分数均有不同程度的提升,其中,BO与XL等级烟叶配伍可最大程度地提高烟叶的内在质量。③所建立的评价模型能够通过少数关键化学指标实现烟叶内在质量的快速、高效分级。应用工业分级烟叶的内在质量评价结果可为复烤模块配方提供指导。

In order to achieve accurate,fast and efficient grading of tobacco by a more scientific and systematic way,reducing sugar/total nitrogen ratio(Kovalenko index),total nitrogen/nicotine ratio and nicotine mass fraction were used as the main evaluation indexes for tobacco quality.An intrinsic quality evaluation model for Yunnan tobacco leaves was developed based on the Chi-square function,which is non-linear,non-monotonic and asymmetric,and the distribution of chemical indexes of the tobacco leaves in redried modules with different appearance and sensory quality grades.Based on the developed model and the near-infrared spectral data,the intrinsic quality of leaves in different redried modules of Hongta Group was evaluated.The results showed that:1)The results were highly related to the trends of tobacco appearance and sensory quality classification.2)The results were improved to different degrees after blending the leaves of lower quality scores with the leaves of complementary chemical indexes in certain proportions(e.g.the upper leaves with higher nicotine mass fraction and the lower leaves with lower nicotine mass fraction).Among them,the combination of leaves of BO and XL grades could promote the intrinsic quality of the blends to the greatest extent.3)The developed model could achieve rapid and efficient grading of tobacco intrinsic quality by a few key chemical indexes.Furthermore,the application of the intrinsic quality evaluation results of industrially graded tobacco could provide guidance for the formulation of the redried modules