| Chromatographic separation of biogenic amines was carried out. The HPLC unit(Agilent 1260,USA), pre-column derivatization of the amines with dansyl chloride. Quantitative methods using Agilent C18, mobile phase of methanol and ultrapure water, using gradient elution procedure, flow rate of 1.0 ml/min, column temperature 30 ℃, UV detection wavelength of 254 nm. The results showed that the correlation coefficients were greater than 0.99(R2> 0.99), the linear range of 0.05 ~ 50 mg/L. The limit of detection was from 0.02 mg/L to 0.11 mg/L, the recovery were 87.67%~101.00%, relative standard deviation were below 3.72%. The detection limits were approximately 0.02mg/L for all standard amine solutions analyzed.There is a huge risk in view of biogenic amines in food safety, excessive intake of biogenic amines is harmful to human body, therefore 6 kinds of beer and 8 kinds of imported beer have been detected the content of biogenic amines with the optimization method. Results showed that the tryptamine and putrescine in all beer can be checked out. The biogenic amine content of beer were varieties, the total biogenic amine averaged 17.92 mg/L, range from 13.64 to 22.78 mg/L. The raw materials include malt and hops in the brewing water were also tested. It showed that the malt and hops were the main source of biogenic amines in beer, the highest content of biogenic amines in malt is putrescine 45.92 mg/K g, tryptamine was 14.8 mg/K g. Tryptamine in hop is 25.5 mg/Kg more than the putrescine is 11.52 mg/Kg and several other kinds of biogenic amines. We have not detected biogenic amine in the brewing water. The biogenic amine content in beer fermentation process has been tracked, further understanding biogenic amines in the process of change.According to the mechanism of biogenic amine formation, the relation among the substrate amino acids, microbial species, and biomass has been carried out. Finding that, Biogenic amine type has the substrate specificity; Specific amino acid decarboxylase can only work on the specific amino acid substrates. The content of biogenic amines was related to biomass and substrate and the content of amino acids respectively. Compared the ability of produce amine between lactic acid bacteria strains stored In laboratory isolated from beer and a standard strain which was isolated from fodder,Two strains can decarboxylate tyrosine specifically. The optimal pH of lactic acid bacteria strains and standard strains were 5.0 and 5.5 respectively. The tyrosine decarboxylase will work under the condition of coenzyme VB6. The experimental results show that laboratory preservation strains have stronger tyrosine decarboxylase activity. |
