Optimization On The The Packing Process And Evaluation On Quality Of Prepared Salads

This paper studies the effects of three packagings(mixed,semi-mixed and split packaging)on the quality of Prepared chicken salad and draws a conclusion that split packaging is the best choice.It further researches the effects of modified atmosphere packaging(MAP)on the quality of Prepared vegetable salad and shows that the best volume fraction proportion of O2: CO2:N2 for MA fresh-keeping is 5%:5%:90%.The Prepared vegetable salad is a mixture of lettuce,chrysanthemum,carrots,sweet pepper,purple cabbage.This paper also analyses the effect of 1-methylcyclopropene(1-MCP)and controlled atmosphere(CA)packaging on the quality of Prepared salads.The research contents and conclusions are as follows:(1)The ingredients of Prepared chicken salad are vegetables,chicken and salad sauce.Three different packagings are used for Prepared chicken salad.They are mixed,semi-mixed and split packaging.Among them,semi-mixed packaging includes vegetable & chicken mixed packaging,salad sauce separate packaging.The chicken salad is preserved at 4 ℃ and its total bacterial count,colibacillus,color,flavor,texture,gas concentration and sensory evaluation are studied at this temperature.The study shows that its flavor changes on the first day,the colibacillus exceeds a threshold value on the third day and that the total bacterial count exceeds the threshold value on the fourth day when applied mixed packaging.When applied semi-mixed packaging,the chicken salad’s flavor changes on the third day;its colibacillus exceeds a threshold value on the second day and the total bacterial count exceeds the threshold value on the third day.The study indicates that the chicken salad’s flavor changes on the fifth day,its colibacillus and the total bacterial count are both under the threshold value when applied split packging.The correlation of color and fresh sample is still more than 0.8;the sensory evaluation is still acceptable.Therefore,the split packaging could be the one which maintain the quality of chicken salad best.(2)Prepared vegetable salad adopts MAP.Three groups of gas volume fraction of O2: CO2:N2 are5%:92%、5%:5%:90%、5%:3%:92%.This vegetable salad is also preserved at 4℃.Its color,total bacterial count,colibacillus,flavor,weight loss rate,hardness and crispness,sensuality are evaluated every other day.The results shows that,Compared with the air control group,the three MA groups could reduce the change of color,the hardness and crispness of sweet pepper to a certain degree;the three MA groups keeps the salad’s flavor,reduces the weight loss rate and inhibits the growth of total bacterial count and colibacillus.The group of gas volume fraction of O2: CO2:N2 5%:5%:90% is selected as the best one to preserve salad’s quality.Compared with the air control group,the color correlation of the fresh sample is significantly increased by 65% and the weight loss rate is decreased by 33%.The total bacterial count and colibacillus are within the safety threshold;the sensory score is the highest.(3)The vegetable salad is packaged with MAP(O2: CO2:N2 5%: 5%:90%),partial 1-MCP treatment combined atmosphere,all 1-MCP treatment combined atmosphere.Preserve the salad at 4 °C.Measure its color,flavor,texture,weight loss rate,sensuality and other indicators every other day.Compared with non-1-MCP treatment combined atmosphere group,the three groups are able to reduce the change of color,the hardness of sweet pepper,and preserve the flavor of salad.The salad colors of red,green and blue are the nearest to the original ones in partial 1-MCP treatment combined atmosphere group on the fifth day.The color correlations are 0.85、0.91、0.84 respectively.The best color and flavor difference were found in 5 d storage period,the hardness of tomato and pepper was the best,and the weight loss rate was significantly decreased by 90% compared with single atmosphere.Its sensory score(7.26)is the highest.Compared with all 1-MCP treatment combined atmosphere group,the potato hardness is increased by 27% and the weight loss rate is significantly decrea sed by 90%.Adopting partial 1-MCP treatment combined atmosphere can preserve salad best.(4)Five common salad ingredients were identified and analyzed for their color and nutrient composition to suit different populations.