Abstract: The moistening process is an important step of processing Chinese medicinal materials.It should be less soaking and more moistening,and when the Chinese medicinal materials is soaked,the water should just run out.The water permeability and the changes of texture of medicinal materials during the moistening process will be reflected in the changes of multiple indicators such as water absorption,water phase,hardness,compression cycle work,and index component content.In this paper,modern analytical techniques are used to intuitively and quantitatively characterize the changes of moisture and texture characteristics in the moistening process of Magnoliae Officinalis Cortex,in order to reveal the scientific connotation of traditional experience of moistening process of Magnoliae Officinalis Cortex.The water absorption kinetics curve was used to evaluate the dynamic change of water absorption.The phase and distribution of water were analyzed by using low field nuclear magnetic resonance and imaging technology.The texture characteristics were measured with texture analyzer.The content of index components was determined by HPLC method.The results showed that the water absorption rate increased with the increase of moistening temperature and decreased with the increase of the weight and length of Magnoliae Officinalis Cortex.During the moistening process of Magnoliae officinalis Cortex,water gradually infiltrated from outside to inside,and the proportion of bound water and free water changed continuously.Within 8 h,the proportion of bound water decreased from 92.82% to56.00%,and the proportion of free water increased from 7.180% to 44.00%.The low-field nuclear magnetic resonance imaging showed that the water had been evenly distributed throughout the medicinal material after 8 hours of moistening,and there was no internal dryness.The analysis of texture characteristics showed that the hardness and compression power decreased with the increase of moistening time.From 0 h to 8 h,the hardness decreased from 2 859 g to 569 g,and the compression cycle power decreased from 130 300 kJ to 31 900 kJ.The hardness of medicinal materials was moderate when the moistening time was 8 h.With the extension of moistening time,the content of magnolol and honokiol decreased gradually,indicating that the longer the moistening time was,the more effective components would be lost.This study could provide data support for explaining the scientific connotation of the traditional experience of the moistening process of Magnoliae Officinalis Cortex,and provide reference for the moistening of other bark medicinal materials.

Key words: Magnoliae Officinalis Cortex, moistening process, multiple indicators quantification, water absorption curve, low-field nuclear magnetic resonance, texture characteristics