Research On The Regulation Of Storage Physiology And Quality Of Chestnut By Low Power Microwave Combined With Preservatives

Chestnut is rich in nutrition and has high nutritional value and medicinal value.It is widely distributed in China and has large output and high economic value.However,chestnut has high moisture content,respiratory intensity,postharvest physiology and metabolism.And it is easy weight loss,rot,moth and germination.Improper storage methods can cause serious loss of Chestnut.So far,we use cold storage method commonly to storage chestnut,but cold storage method still did not solve the problems of weight loss and rot.So exploring new storage methods is very necessary.In this experiment,we use Anhui Dabie Mountain"Dahongpao"chestnut as the experimental materials,and adopt a low power microwave,1-MCP?1-methylcyclopropene?,chlorine dioxide,natamycin compounded fruit wax to treat chestnut,then screened the effective range of microwave power,1-MCP concentration and ClO₂ concentration,carry out three factors and three levels orthogonal test.In order to further study the effects of low power microwave treatment on storage effect of chestnut,we also carried out two times of microwave treatment.All the treatment groups were stored at the temperature of 2⁴?,the relative humidity of 85⁹2%in cold storage,each 30d sample and determina respiration rate,index and physiological and biochemical indexes of quality of chestnut.The study aimed to explore the regulation of low power microwave combined with different preservative treatments on the storage physiology and quality of chestnut,and hope to provide the basis for the preservation of microwave technology,to find a new method of chestnut storage.The results are as follows:1.The test results of screening the microwave treatment conditions showed that the temperature of the pulp was controlled below 35?,and the effect of heat treatment was avoided,then determine finally that the treatment time was 3min,and the output power was 65,130,195,260,325W.2.Low power microwave treating chestnut test results show that respiratory intensity of 65 and 195 W treatment groups is 27.53,34.47 CO₂ mg/kg·h,they are lower than the control group 45.29 CO₂ mg/kg·h.195W treatment could inhibit the decrease of Vc and increase the reducing sugar,reducing sugar content is 3.84%,the smallest increase,Vc content decreased at least 11.41 mg/100g.65W group of amylase activity 1.96 mg/?min·g?lower than in the control group 2.23 mg/?min·g?.The catalase activity of 195W with the smallest decline,from a peak of 1430 U/g to 510 U/g,Peroxidase activity peak 130 W appeared at latest and had the smallest decline in 6.18 OD470/min·g.And it can effectively reduce the content of MDA.The weight loss rate and rotting rate of the 260W group are lowest,at 180 d were 0.89%,2.01%,195W treatment group take the second place.The borer rate of 325W group was the lowest 1.50%,195W treatment group take the second place.To sum up,195W treatment group had the best effect.3.1-MCP treating chestnut test results show that the 0.4?g/L group was the best inhibitory effect on respiration,at 180 d 41.87 CO₂ mg/kg·h lower than the control group48.33 CO₂ mg/kg·h;the reducing sugar content of 0.2,0.4?g/L treatment group was 4.99%,5.33%lower than the control group in 5.70%at 180d.The VC content of 0.3?g/L treatment group decreased at least.The amylase activity of 0.4?g/L treatment group is a minimum of 2.18 mg/?min·g?,significantly lower than the control group's 2.57 mg/?min·g?.0.3,0.4?g/L treatment group keep catalase activity stability,reduce the formation of MDA,0.5?g/L treatment group peroxidase activity decreased only 5.55 OD470/min·g;1-MCP will accelerate the weightlessness of chestnut,and the higher the concentration,the higher the weight loss rate;0.2?g/Ltreatment group had significant inhibition on chestnut rot,other treatments had no inhibitory effect;0.4?g/L treatment group at 30 d of the moth was the lowest,1.21%.In summary,0.4?g/L treatment group had the best effect.4.Screening preservative.The chlorine dioxide treatment had a significant inhibitory effect on the decay rate and the moth rate.Among them,the 150 mg/mL treatment group was the most effective,and the final decay rate and moth rate were only 1.95%,2.13%.There was no obvious effect on the decay rate and the moth rate of Chinese chestnut treated with the natamycin compound fruit wax,but the inhibition of weight loss was significant,The weight loss rate of the treatment group were 1.82%,1.90%,1.93%,2.01%,compared with 2.35%in the control group,and the fruit wax plays a major role.5.Orthogonal composite treatment can better inhibit the physiological and biochemical changes of chestnut,keep the fresh chestnut,delay the quality change,prolong the storage period.The combination of the microwave power of 195W?3min?,1-MCP concentration of 0.3 g/L,ClO₂ concentration of 150mg/L has the best storage effect.6.Two times of microwave treatment can effectively reduce the respiration of chestnut,maintain the quality of chestnut,inhibition of physiological and biochemical changes,so as to achieve the preservation effect.The effect of 195W two treatment group was remarkable,the respiration intensity was low to 25 CO₂ mg/kg·h,reducing sugar was only 3.46%,and the decay rate was 4.07%,significantly lower than that of control group6.61%.The effect of almost all the low power microwave two times is better than that of primary treatment,which 195W two treatment effect is remarkable.