Study On Dimethyl Dicarbonate In Litchi Juice

Litchi is a kind fruit of tropical, subtropical and easily rotten, further processing can not only increase the added value of Litchi, but also meet the needs of different people. With Litchi as raw material, we made the sterilization experiment to microorganisms causing lychee juice deterioration, analysed the strength of bactericidal effect DMDC on different types of culture, the influence of different factors on sterilization effect, the change of volatile flavor composition before and after DMDC processing and the total bacterial count during storage period、pH value and vitamin C content. We study the bactericidal mechanism of DMDC, and get the following conclusion:1. With E. coli as tested bacteria, studied DMDC sterilization effect, optimized the best action condition of DMDC on E. coli, and made sterilization model fitting. The study found that the best work conditions for DMDC:pH 4.0, the concentration 250 ppm, the initial bacterium concentration 104 CFU/ml, within the scope of experimental group, the higher the temperature, the betterSterilization effect; model fitting found that the Weibull distribution on DMDC sterilization model has good fitting effect.2. We made the research for microorganisms representatives yeast and gram-negative, gram-positive and found, as for bactericidal effect of DMDC, Saccharomyces cerevisiae was the best, and then E.coli, Staphylococcus aureus was the weakest.3. With natural lychee juice as raw material, made the study on bactericidal effect of DMDC, optimized the best conditions, and did the measurement on pH value、vitamin C and total bacterial count on fruit juice during storage period, analysed and identified superiority strains after DMDC processing under different temperature treatment. Studies found that the best work conditions DMDC in the lychee juice were consistent with foregoing results, isolated and identified 6 strains which had tolerance on DMDC, among them, intestinal membrane type beads bacterium were the typical tolerance, DMDC had no effect on flavor of litchi juice.4. With E. coli, Staphylococcus aureus, Saccharomyces cerevisiae and intestinal membrane bright beads bacterium as subjects, made the study on bactericidal mechanism of DMDC and found that DMDC on litchi structure integrity had no damage, in addition to the increase in cell membrane permeability of Saccharomyces cerevisiae, cell membrane permeability of several other bacteria had no effect. DMDC sterilization is through the decoration on intracellular enzyme, change enzyme activity, thus make the cell inactivation.