Effects Of Various Treatments On Chilling Injury Of Potato

Storage of potatoes in unsuitable low temperature environments can cause cold damage and affect their edible quality.So in this thesis,potato was used as the research object.In a low temperature,this study focus on the effects of heat,cold shock,UV-C and oxalic acid treatment on the chilling injury of potato,evaluated through physiological and biochemical indexes,include browning degree,weight loss rate,Vc,reducing sugar content,relative conductivity,malondialdehyde,respiration intensity and enzymatic activity of potato during the period of storage.The results show as following:(1)When potatoes were treated at 35?,45?and 55?by heat treatment,it indicates that thermal treatment at 45? could effectively alleviate the chilling injury symptoms of potatoes,reduce the browning degree and weight loss rate of potatoes,inhibit the decrease of Vc content and the increase of reducing sugar content,inhibit the increase of relative conductivity and MDA,maintain the lower respiratory intensity of potatoes,and maintain the higher activity of POD,CAT and SOD.Heat treatment at 55 ?aggravated the occurrence of chilling injury and deteriorated sensory quality of potatoes.Therefore,the effect of 45? treatment was more remarkable.(2)Potatoes were treated at 0? for 1 h,3 h and 5 h.The cold shock treatment for 3 h significantly reduced the chilling injury symptoms of potatoes,inhibited the browning degree and the increase of weight loss rate of potato,delayed the loss of Vc content,inhibited the increase of reducing sugar and MDA content,and decreased the relative conductivity and maintained the respiratory intensity at a lower level and better sensory quality.The activity of POD,CAT,SOD was higher.Therefore,the effect of 3 h cold stress treatment on the inhibition of potato chilling injury was the most significant.(3)Potatoes were conducted by UV-C for 2 KJ/m~2,4 KJ/m~2 and 6 KJ/m~2.It shows that 6 KJ/m~2 UV-C treatment could significantly reduce the chilling injury symptoms of potatoes,inhibit browning of potato,maintain Vc content a higher level,delay the increase of relative conductivity,MDA content and respiratory intensity.The activity of POD,CAT,SOD and storage quality in potato tubers were higher than these in the control group.The effects of 2 KJ/m~2 and 4 KJ/m~2 treatments on inhibiting browning,reducing sugar content and increasing MDA content in potato were not significantly different from each other during the whole storage period.Therefore,the treatment effect of 6 KJ/m~2 UV-C was more effective.(4)potatoes were treated with oxalic acid at 5 mmol/L,10 mmol/L and 15 mmol/L.5 mmol/L oxalic acid treatment could significantly reduce the chilling symptoms of potatoes,the degree of browning and the weight loss rate were significantly reduced.The decrease of Vc content and the increase of reducing sugar content were inhibited,and the integrity of cell membrane was protected.The respiration rate of potato was inhibited,the activity of POD,CAT,SOD in potato was maintained,and the adverse effect caused by chilling injury of potato was alleviated.On the contrary,15 mmol/L treatment accelerated the occurrence of chilling injury and aggravated the deterioration of sensory quality.Therefore,5 mmol/L oxalic acid treatment was more effective in inhibiting the occurrence of potato chilling injury.