Research Of Electrolytic Water Treatment On Physiological Quality And Shelf Life Of Ready-to-eat Salad

Vegetables are rich in vitamins,minerals,dietary fiber and other nutrients,the salad mixed with lettuce,green pepper,purple cabbage(three kinds of vegetables)met the daily needs of the human body,at the same time because it is healthy and fast without heating to reduce the loss of nutrients to win the majority of consumers love.This research studied the problems of ready-to-eat salad,such as easy to corrupt,difficult to store during transportation and sale.First of all,we studied the physiological quality changes of ready-to-eat salad after different concentrations electrolytic water cleaning methods.The experimental results showed that the slightly acidic electrolytic water had better cleaning effect.On this basis,the shelf life prediction model was established and verified by detecting the quality changes of ready-to-eat salad under different temperature conditions.The error value was less than 10%.Due to the influence of temperature on the growth and reproduction of microorganisms,food spoilage occurred.Therefore,high-throughput sequencing technology was used to analyze the dynamic changes of microorganisms and dominant spoilage bacteria in each component of ready-to-eat salad during storage.The research results are as follows:1.Studied the influence of electrolytic water cleaning treatment with different concentrations(effective concentration of 30 mg/L of slightly acidic electrolytic water and 50 mg/L of acidic electrolytic water)on the effect of ready-to-eat salad during storage.The ready-to-eat salad mixed with fresh cut purple cabbage,green pepper and lettuce was packed,sterilized and stored in an incubator at 4±1℃.The indexes were measured every 2 d.The results showed that the chlorophyll content of slightly acidic electrolytic water and acid electrolytic water lost 50.1%and 52.6%,respectively.Vitamin C content lost 70.12%and 71.58%respectively.The antibacterial effect of acid electrolytic water was better than that of slightly acid electrolytic water,but the difference was not obvious.At the end of storage,ready-to-eat salad treated with slightly acidic electrolytic water was superior to that treated with acidic electrolytic water in sensory quality.The comprehensive analysis of all indicators showed that the effect of slightly acidic electrolytic water was better,which made ready-to-eat salad maintain a good state and extended 2 d shelf life.2.Studied the quality changes of ready-to-eat salad under different temperature conditions and the prediction of shelf life model.The experiment material was three mixed vegetables which washed by 30 mg/L of acidic electrolyzed water for 5 minutes and storaged in 5℃,10℃,15℃,20 ℃ constant temperature box.The changes of the total number of colonies,Vitamin C,chlorophyll and other indicators content at different temperatures were measured.First order kinetics model combined with Arrhenius equation,we got the colony,vitamin C,total chlorophyll content of shelf life prediction model of activation energy(EA)were 4.83,3.54,and 3.55 kJ/mol,A0 refers to the former factors were 1.05,3.34×105,7.322×105.The indexes of 10℃were used to validate the model whose relative error about the predicted and measured values were less than 10%.The results showed that the shelf life model can accurately predict the shelf life of ready-to-use salad under the temperature of 5～20℃3.Study the high-throughput sequencing analysis of the dynamic changes of microorganisms in ready-to-eat salads during storage.The experiment material were fresh-cut purple cabbage,green pepper,lettuce,and mixed vegetables(mixed with purple cabbage,green pepper,and lettuce)which washed by effective chlorine concentration of 30 mg/L of acidic electrolytic water for 5 minutes.All vegetables were divided into four groups,the first group was mixed vegetables,the second group was fresh-cut purple cabbage,the third group was fresh-cut green peppers,and the fourth group was fresh-cut lettuce.High-throughput sequencing technology was used to study microbial diversity among components.The results showed that starting from bacterial diversity,a total of 10 classes and 813 genera were identified.There are 7 genera and 124 genera in mixed vegetables,10 genera and 109 genera in purple cabbage,9 genera and 437 genera in green peppers,and 10 genera and 143 genera in lettuce.During the entire storage period,mainly Pseudomonas was the main species,and a large number of microorganisms grew to accelerate the spoilage of ready-to-eat salad.