Multi-index quality evaluation of licorice from six Chinese origins using entropy factor analysis and systematic clustering

This study aimed to establish a comprehensive evaluation system for assessing the quality and classification of licorice from six different origins in China using multiple indicators, including combustion heat, combustion stability, fat, crude fiber, ash, trace element, glycyrrhizic acid (GLA), liquiritin (LI), and amino acid contents. Six types of licorice from Dongsheng District in Ordos, Inner Mongolia, Huimin District in Hohhot, Inner Mongolia, Guyang County in Baotou, Inner Mongolia, Linhe District in Bayanzhuoer City, Xinjiang, Kashgar Prefecture in Xinjiang, and Yining County in Yili, Xinjiang, were selected as research objects to determine the combustion heat, combustion stability, fat, crude fiber, ash, trace element, glycyrrhizic acid (GLA), liquiritin (LI), and amino acid contents. The heat of combustion is a crucial metric for assessing the energy content of substances, thereby reflecting the quality of medicinal materials. The thermal stability of traditional Chinese herbal medicines is associated primarily with their ability to preserve their chemical structure and biological activity when subjected to heating processes, such as boiling, brewing, heating, or storage. Using gray pattern recognition (GPR), entropy factor analysis (EFA), and systematic clustering analysis (SCA), comprehensive evaluation systems were constructed for six licorice samples based on nutritional indicators, including multiple indicators of the heat of combustion, combustibility (licorice combustion stability), fat content, amino acid content, ash content, crude fiber content, glycyrrhizic acid (GLA), liquiritin (LI), and trace element content. Using entropy factor analysis based on 39 variables, the quality ranking of the six licorice samples was as follows: licorice from Dongsheng District, Ordos, Inner Mongolia > licorice from Yining County, Yili, Xinjiang> licorice from Guyang County, Baotou, Inner Mongolia> licorice from Hohhot Huimin District, Inner Mongolia> licorice from Kashgar Prefecture, Xinjiang > licorice from Linhe District, Bayanzhuoer City, Inner Mongolia. The results of the systematic clustering analysis (SCA) indicated that the licorice samples could be classified into three distinct categories and that the 39 variables could be grouped into four groups. This study has significant theoretical and practical implications for the determination and comprehensive evaluation of multiple quality indicators of licorice.