Study On The Degradation Of Nitrite By Lactobacillus Plantarum 5-7-3

In recent years,the role of lactic acid bacteria in the degradation of nitrite?Nitrite,NIT?has attracted extensive attention.It is of great practical significance to study its action law.In this experiment,a strain of Lactobacillus plantarum 5-7-3 with high efficiency degradation of NIT preserved by the Key Laboratory of Dairy Biotechnology and Safety Control of Jiangsu Province was studied.The organic acid produced by fermentation was studied for NIT.Degradation law,clarify the effect of probiotics on the nutrient composition of kimchi and verify the action of organic acid degradation NIT.The main research contents and results of the experiment are as follows?1?L.plantarum 5-7-3 growth characteristics and degradation of NIT related characteristics:optimum growth temperature of 37 0 C,faster growth rate,good acid and salt tolerance;L.plantarum 5-7-3 has a good ability to degrade NIT,and the degradation rate is as high as 83.96%at 36 h.The results show that the number of viable bacteria and titration acidity in the culture process are significantly negatively correlated with the NIT degradation rate,and the degradation rate between pH and NIT is significant.Positive correlation.L.plantarum 5-7-3 Degradation NIT optimal culture conditions are:NaNO₂ concentration 50 ?g/mL,culture temperature 37 ?,initial pH 6.5,inoculation age 12 h,inoculum 6%?2?Study on the degradation of NIT by organic acid produced by lactic acid bacteria fermentation:The change of organic acid content in the fermentation process of L.plantarum 5-7-3 was determined and correlated with NIT content.The results showed that:L plantarum 5-7-3 The organic acid content in the fermentation process was significantly negatively correlated with the NIT content.The correlation of each organic acid was:malic acid>lactic acid>succinic acid>oxalic acid>tartaric acid>citric acidThe five strains with good degradation ability were selected as Lactobacillus aeruginosa 106,Lactobacillus plantarum 11,Lactobacillus plantarum F 90-2,Lactobacillus plantarum 97 and Lactobacillus fermentum xd.The degradation rates of NIT were 83.44%and 82.24,82.66%,83.64%,82.11%,the organic acids produced during the fermentation of the five strains were determined and correlated with the NIT content.The results were related to the degradation of NIT by organic acids produced by L.plantarum 5-7-3 fermentation.similar.?3?Effects of L.plantarum 5-7-3 fermentation on the nutrient composition and safety of kimchi:Comparison of natural fermentation and artificial inoculation of L plantarum 5-7-3 fermented kimchi,the results showed that inoculation fermentation The acidity was good.After 9 days of fermentation,the pH and total acid were 3.12 and 0.84%,respectively.The changes of soluble protein content,reducing sugar content and vitamin C content in the two fermentation methods showed a decreasing trend;the solubility produced by inoculation fermentation Protein and reducing sugar are always higher than natural fermentation;the NIT content produced by inoculation fermentation is always lower than that of natural fermentation,and it is only 1.45 mg/kg until 9 days of fermentation.The total number of colonies inoculated with fermented kimchi was always lower than the total number of colonies of naturally fermented kimchi,while the number of lactic acid bacteria was higher than that of natural fermented kimchi.After 9 days of fermentation,it remained at the order of 108;the yeast inoculated with fermented kimchi decreased in the late stage of fermentation,while natural fermentation The number of yeasts in kimchi continued to increase slowly;the number of inoculated fermented molds decreased rapidly,while the number of molds in naturally fermented kimchi changed irregularly.Among the organic acids produced by the two fermentation methods,the content of tartaric acid and lactic acid was the highest,and the content of organic acid inoculated with fermented kimchi was slightly higher than that of natural fermentation.The organic acids produced by the two fermentation methods were negatively correlated with the NIT content,and the action law was basically consistent with the organic acid produced by L.plantarum 5-7-3 fermentation.