Application Of Ozone And Its Combination Treatments In The Vegetable Processing

In this paper, we used freeze-drying (FD) vegetable soap made by a company and scallion buy from market as materials to study on the application of ozone and its combination treatments for sterilization in order to control the aerobic bacterial count under 1000CFU/ml, and the E.coli is negative. At the same time we should make sure of their quality and flavor. FD vegetable block was made by four or more kinds of vegetable that have been seasoning then acrossed into vacuum freeze-drying processing. During the processing of quick-freezen foods there usually have blanching for sterilization and killing enzyme. But for the quick frezen scallion the special commercial value is just because of no blanching. For no blanching the freezen scallion can preserve most of its flavor and eating quality. This is so named sheng-freezen scallion. This paper is just about the addition of ozone and its combination treatments to the processing of FD vegetable block and sheng freezen scallion to control their microorganisms and make sure their quality and flavor.Because of the low temperature during processing and the less water reserve, freeze-drying vegetable soap, which made up of many kinds of vegetables been seasoned and mixed, is easy to have more microorganism retention. Here we have used ozone-ultraviolet with parallel connection and ozone-microwave in series on the evening of the processing as a means of sterilization to control its microorganisms. After the single experiment of ozone gas and ultraviolet radiation sterilization treatment we have study on the effect of different means of connection between them and finally choose the parallel connection for the next experiment. By the orthogonal design experiment that uses MPN as an evaluation index, the optimization conduitions we obtained: the concentration of ozone gas, 0.48 mg/L, the press of ultraviolet radiation, 200 V and keep working 60 min. As a result of sterilization, we can control the aerobic bacterial count under 1000 CFU/ml, and the E.coli is negative and the quality has been protected.Meanwhiles we have used ozone gas–microwave in series as a sterilization treatment. For the low water percentage of FD vegetable block the time that microwave can working is so short. By the uncontinual working of microwave oven we can prolong the working time of it, which can raise some effect of sterilization. After a series of single experimentals we get the optimization conditions: the concentration of ozone gas, 3.36 mg/L, keep working 60 min, the power of microwave, 261.9 W, keep working 45 s. As a result of sterilization, we can control the aerobic bacterial count under 1000 CFU/ml, and the E.coli is negative. After the sensory evaluation and meansure of water percentage and rehydration ratio we find the quality of product has been preserved very well.For the processing of quick freezing scallion we could not use hot bleaching in order to protect its special value in the commercial and food quality. At the same time it will have more microorganism retention. In some company, they would add NaClO treatment to the processing for sterilization that needs to dip in and wash for minutes during the treatment, which will take almost the entire flavors scallion has. Here we study the addition of ozone water and ultrasonic treatment to the sheng-freezen scallion processing on the base of no hot bleaching and NaClO treatment in order to control its aerobic bacterial count under 1000 CFU/ml, and the E.coli is negative. After orthogonal design experiment that uses MPN as an evaluation index the optimization conditions we obtained about ozone-ultrasonic to quick freezing scallion: the concentration of ozone water, 9 mg/L, the power of ultrasonic, 1200 W, and keep working 60 s. Meanwhile preserve its quality and flavors.