Changes And Control Of Nitrite In Fresh-cut Vegetables And Pickle

Nitrite can make the body abnormal, causing methemoglobinemia, or combining with amines in the body in the formation of carcinogenic nitrosamines, then cause digestive system cancer. About 16-43% of nitrite people intake were derived from vegetables and their products. Fresh-cut vegetables and Pickle were main processing, consumption variety. Research showed that content of nitrite increases during storage. To study the source and control technology was one effective way to ensure the safety of vegetables. This paper was to clear source of nitrite and control its content as the target. The law of nitrite, its relevant factors and technology of L-cysteine hydrochloride to clear nitrite of pickle were studied.The main results and conclusions are as follows:Control and origin of nitrite in fresh-cut vegetables during storage: nitrite content of spinach, the total microorganism count and Nitrite Reductase (short for NR) activity generated by microorganism during storage increased with time accumulation, while the in vivo NR of spinach decreased gradually; namely, changes of the in vitro NR activity produced by microbial had coherence with nitrite content; the in vivo NR activity of spinach was high comparatively in early days (1-2 days), and with obvious effect to the cumulation of nitrite; the NR activity was almost lost entirely after 5 days preservation; accumulation of nitrite in spinach during storage rooted from co-transformation of in vivo and in vitro NR, with the in vivo NR playing an important role in early days, and the reason of microbial growth in the latter period.Changes and Control of nitrite of Pickle during storage: the pickle was made by cucumber, cabbage, Chinese cabbage; of these three kinds of vegetables, the nitrite content of pickling cucumber was the lowest. Vacuum package combined with low temperature storage was the optimum process of pickled vegetables. The effect of sterilization management in decreasing the nitrite content was not obvious. When the salt density was 6%, the nitrite content of pickle was obviously lower than that of 4% density. Appropriate increase in L-cysteine hydrochloride dosage and reaction time can boost the clearance rate of nitrite; with hardly any effect with changes of the system pH value, which is similar with clearance rules of Vc. The influencing order of the three factors to the clearance rate of nitrite was: B (L-cysteine hydrochloride concentration)> A (reaction time)> C (system pH); the effect of the factors to scavenge nitrite was significantly with exception of the system pH value. Optimal condition of L-cysteine to clear nitrite was set: L-cysteine hydrochloride salt concentration 0.1%, the reaction time 10min, system pH value 7.5. Adding Vc in the pickling liquid could reduce the nitrite content to a certain degree.