应用近红外光谱判别烟叶等级模型的可靠性及化学成分特征分析

Reliability and Chemical Composition Analysis of Tobacco Leaf Grade Model by Near-Infrared Spectroscopy

应用近红外光谱技术实现农产品产地、质量等级等属性特征的快速、准确鉴别,在农产品的收购、加工中可发挥重要作用。目前,应用近红外技术实现上述目标虽有一些文献报道,但已实际应用的事例却很少,其主要原因在于所建模型的可靠性尚存在一定问题。以来自四川省内不同部位(不同等级)的烟叶样品为例,基于主要化学成分,近红外光谱和定性判别结果评价了烟叶等级识别模型的可靠性;并通过探究主要化学成分和光谱特征分析了四川省烟叶的等级特征。研究结果表明:在一定生态产区范围内,可建立可靠性较好的烟叶等级识别模型,物质信息基础和模型识别结果的一致性可验证模型的可靠性。通过探究化学成分和光谱特征,分析了四川省不同等级烟叶具有的化学成分特征:上部烟叶具有低总糖,高烟碱,高总氮,高纤维素,高酰胺的等级特征;中部烟叶具有高总糖,中烟碱,中总氮,中纤维素,中酰胺的等级特征;下部烟叶具有高总糖,低烟碱,低总氮,低纤维素,低酰胺的等级特征。本文得出的依据物质信息基础判定定性模型可靠性的方法,以及基于化学成分和近红外光谱特征分析烟叶等级特征的方法,对其他农产品的建模和化学成分特征分析具有参考价值。

The application of near-infrared spectroscopy technology for the rapid and accurate identification of attributes such as the origin and quality grade of agricultural products can play an important role in the acquisition and processing of agricultural products.However,the practical application of near-infrared technology for qualitative identification is rare because of certain problems related to the reliable of the model.Taking tobacco leaf samples with different parts(grades)in Sichuan Province,China as an example,this paper discusses a method for determining whether it is reliable to a grade identification model according to the main chemical composition,near-infrared spectroscopy and qualitative discrimination results;and a method for analyzing tobacco leaves grade characteristics according to main chemical composition and near-infrared spectroscopy.Within a certain ecological production area,a reliable leaf grade recognition model can be established,and the consistency of the material information base and the model identification results can verify the reliability of the model.By exploring the chemical composition and spectral characteristics,the possible grade characteristics of tobacco leaves in Sichuan Province are analyzed:the upper tobacco leaves have low total sugar,high nicotine,high total nitrogen,high cellulose and high amide content;the middle have high total sugar,middle nicotine,middle total nitrogen,middle cellulose and middle amide content;the lower has a high total sugar,low nicotine,low total nitrogen,low cellulose and low amide content.The methods used herein,such as the method for determining the reliability of qualitative models based on the material information basis and the method for analyzing the characteristics of tobacco grades based on the chemical composition and spectral characteristics,have reference value for modeling the attributes and chemical composition analysis of other agricultural products.