Study On Using Lactobacillus Plantarum To Reduce The Content Of Biogenic Amines In The Fermented Sausage

Fermented sausages are popular in consumers because of their special flavor and easy to preserve.However,many studies have found high contents of biogenic amine in fermented sausages.Biogenic amines are nitrogenous basic compounds which are mainly formed by decarboxylases formed by microorganism.Intaking too much biogenic amines may cause a lot of anaphylactic reactions on consumers such as headache and hypertension,and even cause death in severe cases.Using appropriate starter cultures has been widely considered as one of the most effective methods to minimize the accumulation of biogenic amines.In a previous study,a strain of Lactobacillus plantarum with excellent ability to minimize the content of biogenic amines which was named Fqr has been isolated from Chinese fermented sausages.At first,this strain was used as starter culture to determine its ability to reduce biogenic amines in manufacture of fermented sausage.Then,though in vitro experiments,effect of its supernatant on the growth of enterobacteria and activity of decarboxylases was studied.At last,the effect of this strain on reducing content of biogenic amines with plant extract in fermented sausage was investigated.The detailed process and results are shown as follows:1.Effect of different starter cultures on physicochemical properties and contents of biogenic amines of fermented sausage.This section studied effects of selected starter cultures on reducing accumulation of biogenic amines and physicochemical properties during the ripening of fermented sausages.Starter cultures used were:group of inoculating L.plantarum;group of inoculating Staphylococcus xylosus;group of L.plantarum together with S.xylosus and control group without added starter cultures.Compared with control group,inoculating S.xylosus only had reduced 20%of the content of tyramine,histamine,cadaverine.Inoculating L.plantarum effectively reduced tryptamine,phenylethylamine,putrescine,cadaverine,histamine,tyramine by nearly 100%,100%,86%,63%,82%and 43%,respectively.Compared with only Inoculating L.plantarum,Inoculating of S.xylosus plus L.plantarum had no significant difference on the content of biogenic amines but had a higher score of sensory evaluation.2.Effect of supernatant of L.plantarum on growth and aminegenesis of four EnterobacteriaThis section investigated the inhibition of cells-free supernatant(CFS)and water bathed cells-free supernatant(WCFS)from L.plantarum on cells growth,amine production and related enzymes activity of four amine-positive bacteria,namely,Enterobacter aerogenes,Enterobacter cloacae,Enterococcus faecium and Enterococcus faecalis,respectively.The results showed that compared to MRS broth,which was used as control,both CFS and WCFS caused significant reduction of the cells growth but only caused limited inhibition on related enzymes activities.Meanwhile,when the initial pH value decreased from 6.5 to 4.5,cells growth and decarboxylases activities of four bacteria were significant decreased.These results indicated that the reduction of accumulation of biogenic amines by L.plantarum was mainly resulted from the inhibition on cells growth induced by acidification and extracellular metabolites,but not from the inhibition on relevant enzymes.3.Using starter cultures and plant extract to reduce the content of biogenic amines in fermented sausage.The aim of this section is to select plant extracts can inhibit activities of decarboxylases,and to study the effect of plant extract and starter cultures on reducing content of biogenic amines.At first,inhibition of four kinds of plant extracts on activities of decarboxylases was studied,and the result showed that the rosemary had the strongest inhibitory effect.Then,seven groups of sausage with different treatment were made to study the reduction of L.plantarum plus rosemary extract on accumulation of biogenic amines.The results indicated that to significantly reduce the content of biogenic amines,the amount of rosemary extract must up to 0.2g/kg.When added with L.plantarum,0.2g/kg rosemary extract had no significant inhibition on growth of enterobacteria but had a significant inhibition on contents of cadaverine,putrescine and tyramine.