Study On Air-conditioned Packaging And Low-temperature Plasma Technology Of Daylily

This paper selects the best combination point of picking maturity and storage temperature of daylilies from Ningxia as the research object.On this basis,the effect of MAP on the quality and physiological characteristics of daylily was studied,and the optimal initial gas ratio was obtained.The effect of low temperature plasma treatment on the germicidal and fresh-keeping of daylily was studied,the technology of low temperature plasma treatment was optimized,and the effect of low temperature plasma co-air-regulated packaging on the fresh-keeping of daylily was explored.In addition,a low temperature plasma processor was designed to further study the application of low temperature plasma technology in the preservation of daylily.The main results are as follows:(1)In the storage period under three temperature gradients(-1?,1?,3?),the 80%ripe daylily could better maintain its original quality,the temperature was too low was not conducive to the 80%ripe daylily storage.From the storage period,the quality of daylilies and other aspects of comprehensive consideration,should pick 80 ripe daylilies storage,storage temperature of 1?.(2)The results of air conditioning test showed that the air conditioning package had obvious effect on extending the shelf life of 80 mature daylily.According to the study,the initial gas concentration ratio controlled at 6%CO2+3%O2+91%N2 can better maintain the color,flowering rate and hardness of 80%daylily,delay the decline rate of TSS and Vc content,inhibit the increase of respiration intensity and weight loss rate,and extend the shelf life to 30 days.(3)Using response surface optimization method and taking the comprehensive evaluation value as the response value,the optimal low temperature plasma(DBD)treatment of non-packed daylilies was obtained as follows:treatment time 8s,power supply 34W,electrode spacing 16mm,comprehensive evaluation value 0.913.The treatment process was conducive to the sterilization and preservation of 80%daylilies.Through response surface analysis,it was concluded that the primary and secondary relationships of DBD affecting the comprehensive evaluation value of daylily were:power power>Plate spacing>Processing time.Based on the optimal response surface process,the 80 mature daylilies were first treated and then packed in air-conditioned packaging(6%CO2+3%O2+91%N2)to compare the differences between the indexes of low-temperature plasma co-air-conditioned packaging and single air-conditioned packaging during a specific period of storage.The experimental results showed that there was no significant difference between each index and CK except hardness when stored for 18d(P>0.05);When stored for 30 days,the a and b values and weight loss rates of daylilies in the treatment group were significantly different from those of CK(P<0.05);At the end of storage,the color and quality of daylilies in the treatment group were yellow and slightly decreased,indicating that DBD treatment followed by air-regulated packaging was not conducive to long-term storage of daylilies.It was suggested that the experimental study of daylilies treated with DBD should be preferred in the later stage.(4)A continuous low temperature plasma treatment testing machine is designed.The overall layout designwas made for the mechanism parts of the equipment,and the conveying and lifting mechanism were designed and calculated respectively.Among them,the transmission speed of the working conveyor belt was 0.48m/s,and the lifting speed of the ball screw was 5.66mm/s.The control system adopted Mitsubishi PLC design program.the cycle working time was 15 s/time.The size of the electrode plate was 20cm×14cm,and the effective spacing of the electrode plate is 20cm.The used and matching of all electrical components follow the principle of scientific safety and efficiency,and basically met the design requirements of low-temperature plasma treatment.