Decrease Of N-nitrosamines By Lactobacillus Pentosus R3 And Its Utilization In Sausage Fermentation

Recently,the safety of meat products has attracted increasing attention worldwide.N-Nitrosamines(NAs)are common carcinogen of meat products.Decrease of NAs by microbial fermentation became a new study field.In this study,the strain with the most effective in decreasing NAs was selected in a model system from the five meat-borne bacteria,elucidated the mechanism of NAs detoxification and then applied in sausage fermentation to evaluate its effects on NAs content,bacterial communities,quality and physi-chemical characteristics of sausage.The results showed that:(1)Lactobacillus pentosus R3 was found to be the most effective in decreasing NAs in MRS broth,with a rate of 22% for N-nitrosodimethylamine(NDMA)and 23% for N-nitrosodiethylamine(NDEA)after cultivatation at 37°C with shaking(145 rpm)for 20 h.(2)The content of NDMA and NDEA was decreased through degradation of L.pentosus R3 cells that was independent of direct absorption.Surface layer protein located on cell debris was responsible for this degradation.Surface layer protein was a hypothetical protein according to the result of mass spectrometry identification.(3)L.pentosus R3 inoculation could promote the colour formation and myofibrillar proteins degradation,accelerate the dehydration process and enhance the storability;both the textural and sensory qualities of sausage were well acceptable.(4)In the later stage of ripening,NAs content,nitrite residue,carbonyl content,total volatile basic nitrogen,thiobarbituric acid value,p H value,and water activity of the sausage inoculated with L.pentosus R3 were significantly lower than the control(P<0.05).(5)L.pentosus R3 inoculation could enhance the competitiveness of dominant bacteria and inhibite the growth of undesirable microbes.The bacteria obtained from L.pentosus R3-inoculated sausage have the ability to degrade NAs.