| In recent years,researchers have been paying more and more attention to the safety of wine.Ethyl carbamate(EC)and biogenic amines(BAs)are toxic substances in wine.Studies have shown that the causes of the production of ethyl carbamate and biogenic amines in wine are mainly from some arginine and citrulline in the raw materials and the fermentation process and the metabolites of the yeast itself.Therefore,the different production areas,varieties;raw materials and fermentation process made the content of ethyl carbamate and biogenic amines in the brewed wine different.This study focused on the formation of ethyl carbamate and biogenic amines in the brewing process of Cabernet Sauvignon grapes from the east foothill of the Helan Mountains in Ningxia.The main contents are as follows:(1)Fermentation of different Saccharomyces cerevisiae:13 kinds of yeasts were used to make wine under the same fermentation conditions,and anino acid,ethyl carbamate was measured.It was found that the content of ethyl carbamate produced by fermentation of 13 kinds of Saccharomyces cerevisiae was quite different,among which F15 Saccharomyces cerevisiae produces a range of ethyl carbamate in the wine,reaching from 3.92 ?g/L to 3.42 ?g/L.Argine,urea,citrulline varied greatly in the femation.Various saccharomyces cerevisiae have different biological capacity of nitrogen metabolism,which results in different accumulation of intermediate products like urea,as well as different content of ethyl carbamate produced by spontaneous reaction with ethanol.The content of arginine and the yeast to metabolize nitrogen directly affect the content of ethyl carbamate.(2)Different conditions affects the fermentation:The experiment was carried out under different conditions,and the ethyl carbamate and amino acid in the wine brewed under the corresponding conditions was determined to be the highest.The amount of ethyl carbamate produced under the inoculum and at the fermentation temperature significantly increased.The content of biogenic amines mainly comes from the autolysis of yeast.The content is little,which has little effect on the whole.(3)Malic acid-lactic acid fermentation:The OENO 1 Oenococcus oeni lactic acid bacteria were used for secondary fermentation to determine the contents of amino acids,biogenic amines and ethyl carbamate after fermentation under different fermentation conditions.Experiments show that after malic acid-lactic acid fermentation,the contents of biogenic amine and ethyl carbamate in wine significantly increased.The biogenic amines are mainly ?-phenethylamine,cadaverine,histamine,spermine,tyramine and putrescine,of which spermine content is the most.The reason is that the lactic acid bacteria itself carries the gene for producing amino acid decarboxylase,which causes the amino acid in the wine to decarboxylate under the action of the amino acid decarboxylase produced by it to form a biogenic amine,and the amino acid decarboxylase can also deacetylate the arginine through the lactic acid bacteria.The aminotransferase pathway produces citrulline lactic acid bacteria to cause arginine to form citrulline under the action of deaminase,and spontaneously react with ethanol to form ethyl carbamate,released into the grapevine can be,and.Lactic acid bacteria have an amino acid decarboxylase activity.A sufficient amount of amino acids in the matrix results in more biogenic amine production.The higher the inoculation amount,the more amino acid decarboxylase and deaminase produced by lactic acid bacteria,and the further reaction produces biogenic amine and ethyl carbamate containing.The more the amount;the moderate increase of the fermentation temperature accelerates the reaction rate,which is favorable for the formation rate of ethyl carbamate and biogenic amine.The higher the temperature,the more the contents.(4)Brewing methods:It adopts containeis like oak barrels,stainless steel tanks,and bottle to brew wine.The same brewing methods method is used for brewing methods wines under different brewing methods temperatures and time conditions,and ethyl carbamate and biogenic amines are determined.Experiments have shown that the content of ethyl carbamate and biogenic amines after brewing methods is increased in the three brewing methods.Under different brewing methods conditions,the temperature rises and the brewing methods time is prolonged,and the contents of ethyl carbamate and biogenic amines increased.The cause is that the high temperature conditions and long-term brewing methods produce the arginine and ornithine.The ethyl carbamate content in the wine is increased.During the brewing methods process,the amino acid decarboxylase secreted by the residual lactie acid bacteria ean decarboxylate the amino acids in the wine to produce biogenic amines.At the same time,the protein substances in the yeast residues are released and finally degraded into amino acids,providing a substrate for the production of biogenic amines. |
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