| The consumption demand of fresh-cut potatoes has become stronger in recent years.However,after the fresh-cut potatoes are mechanically cut,the internal tissue cells are directly exposed to the air,and they are susceptible to direct microbial invasion and spoilage.In addition,potatoes contain a large amount of phenolic substances.Obvious browning occurs,which in turn causes the shelf quality to decrease.Therefore,in recent years,the preservation of fresh-cut potatoes and the improvement of shelf quality have attracted much attention.In this project,the "Jizhang 12" potato was used as the material to study the effect and mechanism of salicylic acid(SA)and its derivative methyl salicylate(Me SA)on the quality of fresh-cut potatoes,And developed a new fresh-cut potato preservative based on this.The main results are as follows:1.In order to study the improvement of the quality of fresh-cut potatoes by SA and Me SA and clarify their optimal concentration,0.1 mmol/L,0.5 mmol/L,1.0mmol/L,1.5 mmol/L,2.0 mmol/L were used respectively.SA,Me SA,and distilled water were immersed in the control group for 10 minutes and drained,and the sensory score,texture hardness,color,ascorbic acid content,starch content,and total number of colonies were measured.The results showed that the total number of colonies of fresh-cut potatoes treated with exogenous 1.0mmol/L SA and 0.5mmol/L Me SA were significantly lower(P<0.05)than the control group,sensory score,texture hardness,color,ascorbic acid content,starch content The index was significantly higher(P<0.05)than the control group,indicating that the appropriate concentration of SA and its derivatives delayed the spoilage process of fresh-cut potatoes,maintained better sensory quality,and significantly improved the antioxidant capacity and maintained nutrition Quality,maintaining good membrane permeability,extending the storage period of fresh-cut potatoes,the most suitable form of action is Me SA,and the optimum concentration of action is 0.5 mmol/L.2.In order to study the mechanism of SA and its derivatives to improve the quality of fresh-cut potatoes,fresh-cut potatoes were soaked in 1.0 mmol/L SA and0.5 mmol/L Me SA for 10 minutes,drained,and distilled water was used as a control group.The relative conductivity,Malondialdehyde content,peroxidase activity,polyphenol oxidase activity,catalase activity,superoxide dismutase activity,total phenol content,phenylalanine ammonia lyase activity,β-1,3-glucose Sugar activity,relative expression of St NPR1 gene.The results showed that the electrical conductivity,malondialdehyde content,peroxide activity and polyphenol oxidase activity indexes of fresh-cut potatoes treated with 1.0mmol/L SA and 0.5mmol/L Me SA were significantly lower than those of the control group(P<0.05).The index of superoxide dismutase activity,total phenol content,phenylalanine ammonia lyase activity,β-1,3-glucan activity,and relative expression of St NPR1 gene was significantly higher than that of the control group(P<0.05),indicating that SA,Me SA treatment of fresh-cut potatoes can improve the ability to remove active oxygen,maintain the balance of active oxygen metabolism,improve disease resistance of fresh-cut potatoes,reduce potato browning and deterioration,slow down membrane lipid peroxidation,and increase the content of SA in plants.It can promote the expression of St NPR1 in plant defense pathways.SA and its derivatives may mainly activate fresh-cut potato disease resistance signaling pathways to improve the quality of fresh-cut potatoes through plant system acquired resistance(SAR).3.In order to develop a fresh-cut potato preservative based on SAR,Me SA,citric acid,magnesium chloride,and EDTA-2Na are used as raw materials to optimize the color protection,bacteriostasis and crispness process using orthogonal experiments.The results show that 0.5mmol/L Me SA combined with 0.3% citric acid,0.8% magnesium chloride and 0.3% EDTA-2Na can maintain good product characteristics during storage of fresh-cut potatoes,and this ratio can maintain the storage of fresh-cut potatoes During the process,the sensory quality,hardness and color difference of fresh-cut potatoes were relatively good,and the SA content was significantly(P<0.05)lower than the maximum allowable intake,which was in line with food safety standards. |
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