Correlation of Volume Fractal Dimension Inside Matrix of Plant Materials and Rehydration Behavior

Abstract

Based on the measured results of pore size distribution using an automatic mercury injection apparatus (at scale ≥100 nm), the volume fractal dimensions (Dv) were estimated to characterize the pore size distribution inside the matrix of two plant materials (Astragalus and Chinese Angelica root slices) dried by microwave (200 W) and conventional hot air (60°C). The relationship between the matrix microstructure of dried plant materials and rehydration behavior was discussed by combining scanning electron microscopy (SEM) images and rehydration ratio as well as the physical meaning of Dv and its values. The results demonstrate that Dv is an important parameter in the matrix microstructure of plant materials and could provide a better understanding of the rehydration behavior inside the matrix of porous plant materials.

Keywords:

• Fractal dimension
• Plant materials
• Pore size distribution
• Porous media
• Rehydration

ACKNOWLEDGMENTS

Financial support from the Natural Science Foundation of China (grant 50876073) is gratefully acknowledged. We also thank Tiejun Zhang and Suxiao Gong of Tianjin Institute of Pharmaceutical Research for the identification of Astragalus slices, Hui Wang of the Analyzing and Testing Centre of Tianjin University for scanning electronic microscope tests, Shengping Wang of the School of Chemical Engineering and Technology of Tianjin University for pore distribution testing with the automatic mercury injection apparatus, and Lijuan Zhao of the School of Mechanical Engineering of Tianjin University of Science and Technology for useful comments and suggestions regarding help with the English language in this article.