Font Size: a A A

Study On The Effect Of Environment Factors On The Formation Of Biogenic Amines In Salted Fish

Posted on:2021-04-04Degree:MasterType:Thesis
Country:ChinaCandidate:N QiaoFull Text:PDF
GTID:2381330611967700Subject:Chemical engineering
Abstract/Summary:PDF Full Text Request
Incidents of food poisoning caused by biogenic amines are frequent at home and abroad,most of which are due to the consumption of seafood.The distribution ratio of biogenic amines in food is very high,and it is abundant in seafood,preserved products,and fermented products.Bioamines are produced by bacterial decarboxylation of the corresponding amino acids in food.Ingesting a small amount of biogenic amines usually does not have a harmful effect on human health.When their content in food is too high and the detoxification ability is inhibited or interfered with,biogenic amines can cause healthy problems.If the human body ingests excessively high levels of biogenic amine,it will cause dizziness,blurring,burning sensation in the mouth within 1 to 3 hours,and cannot swallow,itchy,and migraine.Studies have reported that histamine and tyramine are two major biogenic toxins that affect human health.Therefore,this research selects the characteristic salted seafood in Guangdong area to investigate its biogenic amine content,and isolates and screens the strains with high content of histamine and tyramine from the salted fish samples.Study the changes of histamine and tyramine content under different environmental factors(p H,Na Cl).The details are asfollows:(1)The way of pre-column derivatization high performance liquid chromatography was used to investigate the content of biogenic amines in commercially-sold salted fish and chilled fish.Take appropriate amount of fish meat in 5%trichloroacetic acid solution,shake and extract biogenic amine for 2 h.After derivatization with dansyl chloride,the amine content was measured on the machine to obtain the data results.The detected rates of?-phenethylamine,putrescine,cadaverine,histamine,tyramine,and spermidine in salted fish were 20%,100%,83.3%,83.3%,50%,and 23.3%,respectively.The proportion of marinated fish exceeding the international safety limit of histamine(50 mg/kg)is 66.7%,and 44.4%for chilled fish.(2)Amine-producing bacteria were isolated and identified from salted fish in Yangjiang,Guangdong.Take an appropriate amount of fish sample in broth medium containing amino acids.After 24 hours of culture,take a small amount of bacterial solution to confirm the generation of amine by paper electrophoresis,and then inoculate it into Niven medium for purification.Quantitative and qualitative analysis was performed by liquid chromatography,and the total DNA of the obtained suspected strain was extracted,and 16S r DNA fragments were amplified and sequenced to identify strains.A total of 6 strains of amine-producing bacteria,Enterobacter cloacae,Morganella morganii,Bacillus subtilis,Vibrio alginolyticus,and Proteus penneri,Providencia vermicola.(3)To study the changes in amine synthesis of histamine-producing bacteria(Proteus pengii)and tyramine-producing bacteria(Providencia vermicola)under different p H and salt concentrations.The p H gradient is set to 4,5,6,7,and 8,and the salt concentration gradient is set to(0%,2%,4%,6%,8%,10%).The broth containing 0.5%histidine and 0.5%tyrosine was adjusted to the corresponding p H and salt concentration,cultured at 30 ~0C for72 h,and the OD value and amine accumulation of the bacterial solution were measured at intervals of 12 h.As a result,it was found that too high acidity would inhibit bacterial growth and amine synthesis.With the increase of salt concentration,the growth of the bacteria will be inhibited,and the content of histamine produced by Proteus pengantii will decrease,but for Providencia vermicola,the tyramine content will increase significantly after the pickling culture time is higher than 60 h,higher than that of low salt tyramine accumulation at concentration.This shows that the expression of the tyrosine decarboxylase gene of Providencia vermicola under high salt environment is not suppressed.
Keywords/Search Tags:Biogenic amine, salted fish, HPLC, microorganism
PDF Full Text Request
Related items