Effect Of Cold Sterilization Technologies On The Quality Of Heat-sensitive Leafy Vegetables During Storage And Technological Study

Microbial in leafy vegetables is the key factor leading to the spoilage of these foods.Studying the technology of cold sterilization is of great significance to the sterilization of heat-sensitive leafy vegetables.Cold sterilization technology as an emerging technology,not only can kill microorganisms in vegetables,but also to maximize the maintenance of vegetables and their products,color,flavor and nutrients.This article explored the different cold sterilization means of heat-sensitive leafy vegetables storage effect.In accordance with the national provisions and methods,comprehensive biological preservatives,acid oxidation potential water,ultra-high pressure technology,ozone sterilization and other means of sterilization effect,the main results and conclusions are as follows:(1)The leafy vegetables were blanched to achieve the effect of preserving the green.When the blanching temperature was 70? and the time was 30s,the best preservative effect was obtained by Zn2+ of 400mg/L and Cu2+ of 500mg/L.(2)Ozonated water saturation and ozone contact area,resulting in different water quality of saturated ozone time and concentration are different.The half-lives of ozone at different temperatures were different.The ozone solution was aerated for 30s and the ozone content was 27.56 mg/L.The XXkilling rate of each concentration of bacteria solution was over 89.5%.Vegetables were processed at different aeration times and the total number of colonies increased during storage.The longer the aeration time and the lower the number of colonies,the logarithm value of control group had increased from 4.31 to 5.02 of three days earlier than other treatment groups.At day 10,the logarithm value of 40 min treatment and control groups increased to nine.(3)The available chlorine content in undiluted acidic water is 30.57mg/L,pH value is 2.63.With its stock solution for 20 min,the killing logarithm value of leafy vegetables can reach above 3.5.pH and effective chlorine concentration have a serious impact on the bactericidal effect of acidic oxidizing potential water,and the germicidal effect tends to increase with the increase of time and finally tends to be gentle.(4)UV of 254nm treatment of leafy vegetables,with the distance decreases and the increase of time,the total number of colonies decreased.When dealing with leafy leaf 40min,10cm when the spoilage bacteria kill the best,the logarithm value reaching 3.81.(5)Different biological preservatives have different antibacterial effects,Nisin,lysozyme,natamycin and tea polyphenols best antibacterial effect.In the compound proportioning experiment,the response surface method was used to test the results.The results showed that the best compound bactericidal effect was nisin:lysozyme:polyphenols:natamycin = 4:4:9:2,the shelf life was about 10 days.(6)As the pressure increases,the lethality of microorganisms is gradually increasing.The total number of bacteria in Toona sinensis seedlings treated with no extra-high pressure was significantly higher than that of the Toona sinensis seedlings treated with ultra-high pressure.The extra-high pressure of 400Mpa-500Mpa could reduce the logarithm value of bacteria in Toona sinensis seedlings by 2.42.