Study On The Effect Of Acidic Electrolytic Water On The Physiological Characteristics Of Browning And Shelf Life Of Fresh-cut Potatoes

Potatoes(Solanum tuberosum,L),one of the important types of fresh-cut vegetables,are prone to browning during processing,resulting in reduced quality and a shorter shelf life.Therefore,it is of great significance to inhibit the browning of fresh-cut potatoes and maintain the appearance quality and edible value.Acidic electrolytic water(AEW)is commonly used as a preservation method to slow down fruit ripening and senescence and prolong fruit shelf life.In this paper,the effects of different pH AEW treatments(strongly acidic electrolytic water(AcEW,pH=2.0-3.0)and slightly acidic electrolytic water(SAEW,pH=5.0-6.5))on the browning physiological characteristics of fresh-cut potatoes were investigated using "Qingshu 9" potatoes as raw materials.At the same time,the effects of AEW on ROS metabolism and antioxidant enzyme activity of fresh-cut potatoes were studied,and the effects of AEW treatment at the optimal pH value on the physiological and biochemical changes of browning of fresh-cut potatoes at different storage temperatures were further explored.Based on the above experimental data,a prediction model for the shelf life of fresh-cut potatoes was established by combining the kinetic model with the Arrhenius equation,providing a theoretical basis for the study of browning inhibition and quality preservation technology for fresh-cut potatoes.The main findings are as follows:(1)Effects of different pH AEW on the physiological characteristics of browning in fresh-cut potatoesFresh-cut potatoes were treated with AEW at different pH values,and distilled water was used as a control and stored at(4±1℃)for 8 d.The changes in the physiological characteristics of browning in the three different treatment groups were analysed.The results showed that the quality of fresh-cut potatoes after AEW treatment was better than control group.The SAEW and AcEW treatment groups were more effective in delaying the decrease in L*,TSS and hardness,significantly inhibiting the rise in a*,browning and total phenols(P<0.05),and reducing PPO,PAL and POD enzyme activities.In particular,the SAEW treatment group showed the most significant effect,which indicated that the appropriate pH AEW treatment could effectively delay the browning of fresh-cut potatoes and maintain better appearance quality and colour by inhibiting the activities of browning-related enzymes PPO and PAL.(2)Effects of different pH AEW on ROS metabolism and antioxidant enzymes in fresh-cut potatoesFresh-cut potatoes were treated with AEW at different pH values,and distilled water treatment was used as control and stored at(4±1℃)for 8 d.The changes in ROS metabolism and antioxidant enzyme activities of fresh-cut potatoes in the three different treatment groups were analysed.The results showed that AEW treatment significantly inhibited the accumulation of ROS and increased the activity of antioxidant enzymes(P<0.05).Compared with the control group,SAEW and AcEW treatment groups inhibited the accumulation of O2-and H2O2,reduced cell membrane permeability and MDA content,and induced the activity of antioxidant enzymes SOD,CAT and APX,thereby reducing the oxidative damage to cell tissues by ROS.In summary,AEW treatment significantly reduced browning of fresh-cut potatoes during storage,which may be related to the metabolism of ROS.Among them,the inhibition effect of SAEW treatment group on browning was better than AcEW treatment group and control group.(3)Effects of different storage temperatures on physiological and biochemical changes of browning in fresh-cut potatoesFresh-cut potatoes were treated with the best treatment group SAEW and stored at 3℃,7℃ and 10℃,respectively.The effects of different storage temperatures on the physiological and biochemical changes of browning in fresh-cut potatoes during storage were studied.The results showed that compared with 7℃ and 10℃,storage at 3℃ was more conducive to maintaining hardness and TSS content,reducing browning and cell membrane permeability,and inhibiting PPO and PAL enzyme activities.At the same time,the activity of antioxidant enzyme CAT was increased.In summary,storage at 3℃ could significantly reduce the browning rate of fresh-cut potatoes and maintain a good appearance color and shelf life.(4)Establishment of shelf-life prediction model for fresh-cut potatoesAccording to the changes of browning,hardness and TSS content of fresh-cut potatoes at different storage temperatures(3℃,7℃ and 10℃)with storage time,the zero-order and first-order kinetic equations were used for linear fitting,and the Arrhenius equation was used to establish the shelf life prediction model of fresh-cut potatoes,and the validity of the model was verified.The results showed that the browning and TSS content conformed to the zero-order reaction kinetic model,and the hardness conformed to the first-order reaction kinetic model.The determination coefficient R2 of the kinetic model established under the three indicators was greater than 0.9,indicating a good fit of the kinetic models.The relative error of the model of the three indicators was within 15%,indicating that the accuracy of the model prediction was high.Therefore,the shelf life prediction model could better reflect the quality changes of fresh-cut potatoes at different storage temperatures.