Effect of Chlorine and Ozone Solutions on the Microbial Count and Browning Enzymes Activity

• Main Authors: HSU, FANG-JU, 許芳如
• Other Authors: WANG, CHIUN-CHUANG
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/u37gdj

碩士 === 靜宜大學 === 食品營養學系 === 106 === The crispy and nutrient lettuce is the favor of comsumers as they purchase the vegetable salads. In order to extend the shelf life of vegetable salads, some manufacturers may applied pesticides or preservatives into the processing procedure. However, the pesticide and preservative residues are the critical issue of food safety for consumers. The purposes of this study were to investigate the effect of sodium hypochlorite, chlorine dioxide, and ozone treatments on growth of microbial and enzymatic browning of fresh-cut vegetables.In this experiment, washed fresh-cut vegetables were immersed into three solutions of sodium hypochlorite, chlorine dioxide and ozone, respectively, for 0-5 min and detected the total plate count of microbial, coliform and Escherichia coli. Residual chlorine content after treatment of sodium hypochlorite and chlorine dioxide were also measured in this experiment.As well as, the change of activity of polyphenol oxidase and peroxidase of fresh-cut vegetables influencing by ascorbic acid, citric acid, sodium hypochlorite, chlorine dioxide and ozone were also identified, respectively.The results showed that 20 ppm sodium hypochlorite and chlorine dioxide are more lethal than 50 ppm solution. To increase the immersed time increased bactericidal effect in both chlorine solutions. In the treatment of ozone, the total plate count of bacteria significntly decreased as the fresh-cut vegetables were soaked in the ozone solution. However, the total plate count of bacteria did not significantly affect as the soaking time were extended.The residual chlorine of all fresh-cut vegetables after treatment of chlorine solutions were much lower than the regulation (1.0 ppm) of Taiwan Food and Drug Administration. The activity of polyphenol oxidase of fresh-cut vegetables significantly decreasedas treated by ascorbic acid, ozone solution, sodium hypochlorite and chlorine dioxide solution, but no significant effect was found in the ozone treatment. The activity of peroxidase of fresh-cut vegetables significantly decreasedas treated by ascorbic acid, ozone solution, sodium hypochlorite, chlorine dioxide and ozone solution, particularly in the treatment of ascorbic acid solution.