Research On High-Quality And Precise Infrared Drying Of Ginger Based On Cleaning,Cutting And Pretreatment Technology

Ginger(Zingiber officinale Roscoe)is the dominant specialty vegetable of our country.As a spice,it is an indispensable condiment in daily life.In recent years,due to the advantages of long shelf life,easy storage,and wide range of uses,the market demand for dried ginger has increased day by day.Therefore,drying is still the mainstream processing method to increase the value of ginger products.Because ginger is mostly finger-like branches and grows in the soil,dust and dirt are hidden between the cracks,and it will face the problems such as environmental pollution caused by water discharge after washing and excessive ash content caused by incomplete cleaning.Therefore,minimizing resource consumption and effectively cleaning the sediment and microorganisms on the surface of ginger become an important choice for ginger cleaning.In addition,as a tuber plant,ginger is difficult to dry the whole root,so it needs to be cut first.Because there are more fiber structures in the structure,which affects the water transport to a certain extent,it is found that the cutting direction will cause different degrees of damage to the structure in the process of excavation,which further affects the drying process.On this basis,this research explored the precise drying process of ginger.Before drying ginger,this article first screened a variety of cleaning methods and further evaluated it through storage quality.In order to achieve precise drying of ginger,the influence of cutting direction on the moisture transport during the drying process and the quality of the final product was explored,and the most suitable drying method for ginger was screened out.Subsequently,it was proposed to pre-treat the ginger before drying,in order to shorten the drying time,increase the drying efficiency,and further improve the product quality,and finally establish a "cleaning,cutting and pre-treatment combined infrared drying" technology suitable for ginger.(1)This study first compared the effects of various cleaning methods(oscillating,ultrasonic,oscillating after soaking,ultrasonic after soaking,oscillating after soaking,oscillating after soaking and ultrasonic after soaking)combined with water washing and chemical reagent PAA on the cleaning rate of ginger,and carried out an in-depth study through storage quality.The results showed that compared with traditional water washing,PAA as a cleaning agent helped to disperse sediment and exhibited better microbial inactivation rate,which was the first factor to improve the storage stability of PAA.The soaking process before cleaning helps to disperse the sediment and microorganisms in the sample.There is no significant difference between the cleaning rate of the first soaking,then ultrasonic and final vibration and the 30 min ultrasonic sample,which also shows that the synergistic effect of the three cleaning methods is higher than that of the single method,which can reduce the waste of resources and energy consumption.During storage,PAA will affect the color,hardness and respiratory intensity of the sample,while other nutrients and electrolyte leakage rate are mainly affected by ultrasound.Ultrasonic action time longer,the greater the damage to the quality in the process of storage.Therefore,it was found that the three methods combined with PAA cooperative cleaning can improve the quality of ginger in the later storage process while sterilization and decontamination.(2)This study focused on the dehydration processing technology of ginger.First of all,the water transport mechanism of ginger dehydration was understood.The effects of vertical cut and transverse cut combined with common drying technologies(hot air drying,vacuum drying,freeze drying and catalytic infrared drying)on the drying quality of ginger were selected.The results showed that the drying time of the ginger samples after vertical cutting was significantly shortened by 29.6% compared with that of the cross-cut samples,and the microstructures were well preserved,and the ginger samples had good physical properties(such as hardness,color,rehydration rate and wrinkle degree,etc.).However,the cutting method had no significant effect on the nutrient composition.For drying methods,catalytic infrared drying technology has a shorter drying time,which is 28.3～32.4% shorter than hot air drying.It can not only accelerate the drying rate,but also retain the color and nutrition of the material to a large extent.The retention degree of the appearance and quality of ginger sample is second only to freeze drying.But thermal drying process will cause a loss of nutrients,and on this basis,this study proposed the preprocessing before ginger catalytic infrared drying: ethanol osmotic dehydration,microcapsules infiltration and ultrasonic auxiliary seepage,shorten the drying time and improve product quality,in order to achieve the final set up appropriate ginger green,efficient and high quality "cutting pretreatment combined catalytic infrared drying technology.(3)For the pretreatment technology of ultrasound-assisted ethanol osmotic dehydration,firstly the effects of ethanol osmotic dehydration and ultrasound-assisted osmotic dehydration on the drying rate of ginger were investigated,and then the effects on the drying quality of ginger were explored.The results showed that the alcohol osmotic dehydration could destroy the cell wall structure and promote the intracellular water loss,and the water content decreased by 17.5%.After ultrasonic-assisted ethanol osmotic dehydration,the water in the intercellular space of the sample was discharged,and the water content was reduced by 34.1%.Meanwhile,the drying time was shortened by about 58%,which greatly accelerated the dehydration and drying rate.However,after ethanol treatment,the color of the samples decreased and the microstructure was destroyed,which resulted in the inevitable loss of alcohol-soluble substances and the waste of ethanol reagents.However,the main flavor and nutrients in ginger are alcohol-soluble substances.Therefore,the concept of microencapsulation of nutrients was put forward to reduce the loss of nutrients and recycle ethanol at the same time while improving drying rate.(4)For ultrasonic-assisted microcapsule pretreatment,alcohol-soluble nutrients were first microencapsulated to prepare microcapsules,and then the effects of microcapsules and alcohol extract as osmotic solution on the drying quality of ginger were investigated.The results showed that the alcohol extract and microcapsule processing,dry ginger samples had no significant content of nutrients in ascension,after using ultrasonic assisted sample quality improved significantly,the gingerol retention rate increased by 117%,the antioxidant capacity increased by 26～40%,while preserving the unique smell of ginger improve the nutritional value of dry ginger.Therefore,the microencapsulation of nutrients can not only recover ethanol,but also rationally utilize the alcohol-soluble substances in the sample,which realizes the concept of increasing drying rate and improving product quality.The above research results showed that,faced with the problem that ginger structure was complex and difficult to clean,the post-soaking ultrasonic re-oscillation combined with PAA cleaning process established in this study could effectively inactivated microorganisms,improve cleaning rate,reduce energy consumption and improve product quality during storage.Facing the problems of high water content and short storage period of ginger,a longitudinal cutting combined with catalytic infrared drying technology was established to improve the drying rate and product quality of ginger.In face of the problems of long drying time,high energy consumption,loss of nutrients and structural damage,ultrasonic ethanol pretreatment and ultrasonic microcapsule pretreatment technology were proposed in this study.The latter could significantly improve the drying rate and reduce the loss of nutrients,thus obtaining high quality dried ginger.Based on this,this study has derived the best cleaning process(soaking combined with ultrasonic re-oscillation combined with PAA)and the best drying technology process(after slitting,ultrasonic-assisted microcapsule pretreatment combined with catalytic infrared drying technology),which is ginger The green,high-efficiency,energy-saving,and high-quality industrial production provides a certain theoretical basis.