Study On Sterilization And Preservation Of Fruits And Vegetables Using Acidic Electrolyzed Oxidizing Water

Fruits and vegetables are indispensable nutrition source of human’s dietary, it can provide abundant vitamins, dietary fibers, minerals, inorganic salts and other nutrients for people. Because the characteristics of fresh, convenient, rich nutrition and pollution-free, fresh-cut fruits and vegetables are developing rapidly in recent years in China. However, due to the nutritional juice of tissues outflow, a large number of microorganisms breed on the surface of fresh-cut fruits and vegetables, and finally lead to corruption. Mechanical damage caused by segmentation process, activates the respiration and metabolic responses, makes the quality decreased rapidly and finally cause deterioration and aging, which shorten the shelf life, and caused huge losses. Sterilization. In this paper, changes of active chlorine concentration(ACC), oxidation-reduction potential (ORP), pH value of acidic electrolyzed water under different temperature environment with different reservoir vessel were studied, a dissipation dynamics model of ACC was established. Sterilizing effect of acidic electrolyzed water with different concentration of ACC to pathogenic bacteria on fresh-cut pineapples was investigated, sterilization dynamics model is established, and an optimal process parameters is selected through response surface method. This paper also investigated quality influence of acidic electrolyzed water on fresh-cut fruits and vegetables. The main results are as follows:(1) ACC and ORP reduced, pH value increased during storage, and their change range increased with the temperature increased, pH value and ORP were not much difference between brown bottle and transparent bottle storage, but brown bottle storage can effectively inhibit the dissipation of ACC.(2) ACC dissipation followed first order kinetics y=Co·e-k’t during storage and sterilization, correlation coefficient R2 achieved above 0.9 under different conditions. The effect of delay constant of ACC dissipation with different storage temperature conformed to Arrhenius equation, as follows:According to the model, can obtain the ACC of acidic electrolyzed water at storage temperature after a certain period of time. (3) Establish sterilization dynamics model of acidic electrolyzed water to pathogenic bacteria on fresh-cut pineapples, as follows:correlation coefficient R2 achieved above 0.9 under different conditions. (4) In one-factor-at-a-time experiments, under the condition of 4.5g/L NaCl concentrat-ion,20℃,7 min treatment time and 8:1 (mL/g) solid-liquid ratio can respectively reached the maximum bacteria reduction rate. Using response surface analysis on fresh-cut apples in terms of total bacterial count and reduction rate. The optimal conditions for maximum bacterial reduction rate were:4.5g/L concentration,25℃,6.45 min time and 6:1. Under the optimal conditions, the total bacteria count was reduced from 1.14×105 CFU/g to 9.3×103 CFU/g and the bacteria reduction was up to 91.84%.This processing has little effect on pH value and soluble solids of fresh-cut apples, and can effectively inhibit the degradation of vitamin C and browning.(5) Fresh-cut Hami melons were washed with acidic electrolyzed water (AEW), neutral electrolyzed water (NEW), sodium hypochlorite (NaCIO) and tap water. The fresh-keeping effects of these four cleaning solutions were all better than those of the untreated group, and washing with acidic electrolyzed water was the best, it could effectively maintained content of total soluble solids, vita 分é'ŸC and titratable acid, delayed the increasing of malonaldehyde content, restrain the microbial growth and prolong the shelf life of fresh-cut Hami melons.(6) Fresh-cut Hami melons were washed with acidic electrolyzed water(AEW), neutral electrolyzed water (NEW) and sodium hypochlorite (NaCIO). The fresh-keeping effects of these three cleaning solutions were all better than those of the untreated group, and washing with acidic electrolyzed water was the best, it could effectively maintained content of chlorophyll, vitamin C and pH value, delayed the increasing of respiratory intensity and nitrite content, restrain the microbial growth and prolong the shelf life of fresh-cut vegetables.(7) Comparing effects with different cleaning solutions on quality of fresh-cut vegetables, neutral electrolyzed water (NEW) and sodium hypochlorite (NaClO) were better than those of the tap water, they were less efficient than those of acidic electrolyzed water. Therefore, using acidic electrolyzed water (AEW) for pretreatment of fresh-cut fruits and vegetables, not only can reduce the harm of microbial infection, but also can reduce the loss of nutrients and ensure the quality of fresh-cut vegetables during storage.