Infrared-forced Air Drying Dynamics And Moisture Loss Mechanism Of Lonicera Japonica And Salvia Miltiorrhiza Bunge

Flos lonicerae and salvia miltiorrhiza are important traditional Chinese medicinal materials in Shandong Province,which are also the genuine medicinal materials with large market capacity.Flos lonicerae is the dried buds or initial flowers of Lonicera japonica(Lonicera Japonica Thunb).The analalysis of chemical composition shows that flos lonicerae is rich in flavonoids,volatile oil,three terpenes and organic acids,which play an important role in bacteriostasis,detoxification and evacuation of wind heat.salvia miltiorrhiza bunge is the most commonly used traditional Chinese medicine for promoting blood circulation and removing blood stasis.In recent years,more attentions have been paid on the comprehensive utilization and development of flos lonicerae and salvia miltiorrhiza bunge.Control of drying conditions tends to be critical to maintainess of quality.Therefore,the study on the drying kinetics and the mechanism of water loss of flos lonicerae and salvia miltiorrhiza bunge is significantly valuable,which can provide theoretical basis for the research on the processing technology of flos lonicerae and salvia miltiorrhiza bunge.In this study,the main results are as follows:1.Drying characteristics,drying kinetics and product quality of flos lonicerae and salvia miltiorrhiza bunge during infrared-forced air drying: The drying time of both flos lonicerae and salvia miltiorrhiza bunge decreased with the increase of the drying temperature,which are fitted best with the Page model,compared to other models.The Fick’s second law of diffusion was employed to calculate the value of moisture effective diffusivity(Deff)of flos lonicerae and salvia miltiorrhiza bunge,which are in the range of 5.06606 × 10-10 ~ 7.59909× 10-9 m2 /s and 3.24228×10-10~1.29691×10-9 m2/s,respectively.Moreover,these Deff values increased with the increasing drying temperature.The activation energy determined from Arrhenius equation were 33.569 kJ/mol and 41.4328 KJ/mol of flos lonicerae and salvia miltiorrhiza bunge,respectively.The value of △E of flos lonicerae is least while the maximum effective constituent was achieved at 35 ℃.Compared to shade drying,the infrared-forced air drying at 35 ℃ was rather efficient.When dried at the temperature range of 50 ~ 70 ℃,salvia miltiorrhiza bunge had a higher amount of salvianolic acid B and tanshinoneⅡA.2.Analysis on moisture changes of the flos lonicerae and salvia miltiorrhiza bunge during infrared-forced air drying process via low-field NMR: Three different flos loniceraes(three green period,large white period and whole flowering period)were subjected to the infrared radiation at 45°C.Three kinds of water states including bound water,immobilized water and free water were detected in flos lonicerae at different flowering stages,with the similar volume order(immobilized water > bound water > free water).Free water and bound water in flos lonicerae at three green period accounted for higher proportion than that in two others’ periods,whereas immobilized water content was relatively low.During the drying process of flos lonicerae,immobilized water content decreased and bond water content decreased first and then increased.This phenomenon may be resulted from change in the internal water distribution and water content of flos lonicerae,and there was a mutual transformation between different conditions of water.During the initial period of drying,the fluidity of the bound water improved and then it lowed when arriving at the drying final stage.However,fluidity of the bound water at the large white period was continued to decrease.During the drying process,the water content of flos lonicerae had a high correlation with the peak area of immobilized water and total peak area(R2 > 0.9).The NMR technique would provide important clues and useful guides to detect water distribution and variation of the flos lonicerae at different flowering stages.For salvia miltiorrhiza bunge,free water and immobilized water accounted for the higher proportion than bound water.In detail,free water decreased gradually in the whole drying process until being completely dried.The content of bound water gradually increased in the early stage,and then decreased in the last stage of drying.The immobilized water was constantly decreased in the whole stage of drying.The vaules of T2 of free water,immobilized water and bound water decreased during the whole drying process.Low field magnetic resonance imaging for salvia miltiorrhiza bunge indicated that higher moisture content was observed at the below epidermis and above the hollow parts when dried at 65 ℃.Signal strength of the hollow parts is relatively weak due to higher cel ulose content.Last heating leaded to the occurance of moisture migration,which further to cause uniform water distribution.However,the total amount was reduced and the basic water evaporated when dried for 4.5 h.