The Study Of Control Nitrite Content In Vegetable Fermenting Food

Nitrite is a kind of potential carcinogens，controlling its concentration. It is veryimportant for maintaining a safe vegetable fermenting food supply. The paper reviewsthe harm and origin of nitrite，and studies the controlling methods in vegetablefermenting food.In this paper，the influence factors were studied in determination of nitrite infoods with national standard method－Spectrophotometric hydrochloridenaphthylethylenediamine. With Single factor experiments，three factors－time，temperature and the sample pH value on the influence to measurement results werestudied. And then，four factors of pretreatment--the extract pH，the amount ofprecipitant added，water bath temperature and water bath time on the influence tomeasurement results were studied. The results showed that in the pre-operation extractat pH7should be selected or a bit more alkaline. Precipitating agent to join the natureof the sample according to the amount added, but not free to increase the amount.Optional temperature around65℃water bath. Bath time control in15minutes isappropriate. At room temperature not lower than19℃under the conditions, notemperature control in the process of color nitrite. Batch of samples to be tested withthe number of large, uniform color time can be extended to20minutes or25minutes,less impact on test results.To determine the optimal culture conditions of a LAB strain from picklevegetables. Minimum media (MM) supplemented with different saccharides, differentmedium pH and culture temperatures were tested for the best growth of LAB strain.Glucose is the best substitute for the rapid growth of tested LAB strain, with pH5-6,30oC-35oC as the best fermentation conditions. Adding the pure strains of Lactic acidbefore ferment vegetables，nitrite in the vegetable fermentation process early peak time,peak low, the fermentation time is short.Process conditions for the fermentation of vegetables has been studied. WithSingle factor experiments，five factors－fermentation time，the initial fermentationpH，the amount of salt，sugar and other materials amount (onion, garlic) on theinfluence to measurement results were studied. Add some material change in picklingliquid pH，the result is a lower nitrite under the conditions of low pH(4.0). At highertemperatures (25℃) conditions, the formation of nitrosyl peak earlier and lower peak.In the case of low concentrations of salt，nitrite peak early,and the peak is high. In the case of high concentrations of salt, nitrite peaks late, the peak is low. In the higherlevels of sugar (5%) of cases, the nitrite peak early peak, the peak is low. Add theproper amount in the fermentation process garlic and onion juice, which cansignificantly eliminate nitrite in fermented vegetables and adding larger the better.In this paper,the nitrite scavenging ability of ascorbic acid were studied.Theresults show that the solution pH,the concentration of ascorbic acid,alanine,andglucosamine hydrochloride salt have significantly effect on nitrite scavenging ability ofascorbic acid.Under acidic conditions,ascorbic acid showed a higher nitritescavenging.The higher the concentration of ascorbic acid,which is also higher nitritescavenging ability.Alanine and glucosamine hydrochloride could significantly increasenitrite scavenging ability of ascorbic acid. Nitrite peak earlier, the peak is low, thefermentation time is short. It has to use less, high efficiency, and does not affect flavorcharacteristics.A selection from the yeast and lactic acid fermentation of vegetables composed ofspecial bacteria. The most important feature of bacteria is used to overcome the simplefermentation of lactic acid bacteria strains as well as the shortcomings of traditionalcrafts. After inoculation, the fermentation process in vegetables, nitrite early peak time,peak low, the fermentation time is short.