| As a special commodity for disease prevention,treatment and health care,traditional Chinese medicine(TCM)are mainly from natural plants,animals and minerals.The composition is extremely complicated,TCM are susceptible to natural conditions during storage,especially the TCM contain anthraquinone,oils,volatile oils and other components,which will cause spoilage,mildew,discoloration,oily and other deterioration phenomena which will affect the safety of clinical medications and effectiveness.Among them,discoloration as a kind of deterioration phenomenon that occur repeatedly and easily in the process of storage of TCM,and involves many kinds of TCM,such as Angelica Dahurica Benth,Phellodendri Chinensis Cortex,Rhei Radix Et Rhizom Aa,Polygoni Cuspidati Rhizoma Et Radix,Chrysanthemi Flos,Lycii Fructus.Therefore,studying the material basis and influence factors of discoloration during storage has universal significance for solving the problem of discoloration of TCM.The "color" of TCM is closely related to the internal material basis,and it is easily occur changing after the influence of external conditions such as temperature,humidity,air,light,and packaging.Different TCM have different material bases,their impact factors and impact weights also different.Targeted research is necessary.And find out the common law,laying a solid foundation for fundamentally solving the problem of discoloration of TCM.At present,the research on the storage and maintenance of Rhei Radix Et Rhizoma mainly focuses on the storage conditions,packaging methods and storage time on the quality of Rhei Radix Et Rhizoma,but there is no relevant research report on the basis and influence factors of Rhei Radix Et Rhizoma color-changing substances during storage.1.Objective evaluation of the color and change of Rhei Radix Et RhizomaThe source of Rhei Radix Et Rhizoma is from the root and rhizome of Rheum palmatum L.,Rheum tanguticum Maxim.ex Balf.Or Rheum officinale Baill.,family Polygonaceae."Quality evaluation through morphological identification" is the essence of aempirical identification.In traditional,Rhei Radix Et Rhizoma,yellowishbrown,weight,solid,star point,gas scent,is batter than others.Color is an important indicator of its trait evaluation.This study introduced the colorimeter to objectively quantify the change of color value during the storage of rhubarb for the first time,and express the color with L*,a*,b* and E*ab values.The results showed that the L*,a*,b* and E*ab values of Rhei Radix Et Rhizoma showed a fluctuating downward trend during the simulated accelerated test and long-term storage.The results showed that the brightness,redness and yellowness of Rhei Radix Et Rhizoma were reduced to varying degrees during storage.This is consistent with the results of sensory evaluation,that is,the color of Rhei Radix Et Rhizoma is obviously deeper and darker during storage,and gradually darkens.This study laid a foundation for the objective quantification of appearance traits in the Rhei Radix Et Rhizoma quality evaluation system.2.Study on water activity of Rhei Radix Et RhizomaAccording to the basic theory of food preservation and modern research,water activity indicates the true state of water in the material,which expresses the effective degree of water energy can be utilized by chemical reactions and physical processes.This study introduced the stability evaluation index for the first time to explore the correlation between color change and water activity of Rhei Radix Et Rhizoma.The results showed that during the simulated accelerated experiment,the b* and E*ab values were significantly negatively correlated with water activity,indicating that the water activity is closely related to its color change to some extent,but all color values are uncorrelated with moisture content.The results showed that the discoloration of Rhei Radix Et Rhizoma is closely related to its internal moisture,and its evaluation index should select water activity.In order to further study the critical water activity value of discoloration during Rhei Radix Et Rhizoma storage,this experiment provides a new research idea and method for finding the safe water content of Rhei Radix Et Rhizoma,which laids a foundation for the exploration of the effective period of Rhei Radix Et Rhizoma storage.3.Research on the method of simulated accelerated storage experimentalcombine with the method long-term storage experimentalAt present,the field of storage and conservation research of TCM,long-term retention observation method combined with accelerated experimental method is used to predict the stability of TCM.Based on a large number of pre-experiments and preliminary studies,this study design firstly a simulated accelerated storage experiment to study the correlation between color change and material basis during Rhei Radix Et Rhizoma storage process.The consistency of the sample is ensured by“predetermined place of origin,fixed variety,and same batch”,and the storage study period is shortened by controlling the temperature,humidity and illumination of the environment.At the same time,combined with long-term storage experiment results,which show that the color change trend of each group of Rhei Radix Et Rhizoma samples in the simulated accelerated experiment and the long-term storage experiment was consistent in the view of naked eye,they both showed a trend of darkening and darkening.Meanwhile,in terms of chromaticity value measurement,each Long-term storage group samples showed a downward trend in L* value(brightness)and b*value(yellow-blue degree).The a* value(red-green level)and total color difference E*ab expressed downtrend in most groups except for the individual groups.This result is basically consistent with the results of the simulation acceleration experiment,which verifies the reliability of the simulation accelerated experiment.This study provides a demonstration of the research methods of metamorphism phenomenon in the storage of TCM.4.The material basis of discoloration of Rhei Radix Et Rhizoma during storage processTCMs have inherent color that is important quality indicators.According to "Quality evaluation through morphological identification",the science of storage and prevention and modern research,finding that the variation of color reflects the change of endogenous substances of medicinal materials to some extent.On the basis of previous research,this study focuses on the variation of the content of unstable medicinal components before and after discoloration of Rhei Radix Et Rhizoma by simulated accelerated storage experiment,and analyzes the correlation with the chromaticity value of Rhei Radix Et Rhizoma.The results show that: there were asignificant negative correlation between the color change with free anthraquinones and gallic acid content,significantly positively correlated between color change with the content of catechin,which indicated that free anthraquinones,catechin and gallic acid were the material basis for the discoloration of Rhei Radix Et Rhizoma.The main material basis for the discoloration of Rhei Radix Et Rhizoma was found,which pointed out the direction and key points forstudy of the next color change mechanism,and laid a solid foundation for scientifically elucidating the discoloration mechanism of Rhei Radix Et Rhizoma.5.The main Factors affecting the discoloration of Rhei Radix Et Rhizoma during storageIn order to explore the key factors that affect the discoloration of Rhei Radix Et Rhizoma,this study refers to the "Guidelines for the Study of Stability of Traditional Chinese Medicines and Natural Medicines" according to the previous research results of the research group,and by single factor experimental design method sets different water activities,temperatures,humidity,light,and oxygen storage conditions to oobserving and analysis the observations statistical.The results showed that the dominant factors that affect the color change were water activity and humidity compared with temperature,light and oxygen.This will provide a scientific basis for further research on the suitable storage conditions of Rhei Radix Et Rhizoma,and the introduction of a new entry point for the stability index of dry material preservation-"water activity",also provides a new study for the storage and prevention of TCM.The idea has certain demonstration significance.In summary,this paper focuses on the discoloration of Rhei Radix Et Rhizoma,under the guidance of the basic theory of storage and maintenance of TCM,introduces the theory of water preservation in food preservation and modern research results,combined with modern color measurement technology,to find out the material basis of the discoloration problem of Rhei Radix Et Rhizoma.Which can clarify the mechanism and laid a solid foundation for fundamentally studying the prevention and control techniques and strategies of Rhei Radix Et Rhizoma discoloration.It is great significance for the quality evaluation and quality stability control of logisticsand storage links in Rhei Radix Et Rhizoma traceability system. |
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