Analysis And Research On Main Technological Parameters Of Shanxi Mature Vinegar

In this experiment,using continuous temperature monitoring system,microbial pure culture method and SPME/GC-MS to test the temperature of jiulao and cupei,the number of main microorganisms,physicochemical indices and volatile constituents during different fermentation periods of Shanxi mature vinegar.The specific results were as follows:(1)The variation of temperature in different fermentation periods.At alcoholic fermentation(AF)stage of 0 to 3th,temperature ofyjiulao was maintained at 30?35 ?.From 4th day,the temperature of jiulao was gradually reduced.At acetic acid fermentation(AAF)of 0 to 2th,the temperature of cupei rose slowly.From 3th to 9th,over turned pei once a day,the upper,middle and lower layers of cupei temperature would rise,and the upper layer cupei temperature was significantly higher than the medium and the lower temperature of cupei.cupei temperature was changed greatly before and after the over turned.The temperature of upper cupei was reduced by 10 to 15 ?,The temperature of middle cupei was reduced by 4 to 7 ?,The lower of cupei temperature was increased by 3 to 5 ?.From 9th to the end of fermentation,the upper of cupei temperature,middle of cupei temperature,lower of cupei temperature were reduced significantly.(2)The variation regularity of the main microorganism quantity in different fermentation periods.The number of molds were 3.57×105 CFU/g at the beginning of AF.From 0 to 7th,the number of molds were gradually decreased.To the 7th day,the number of molds were perished completely.The molds couldn't be discoveried during the AAF.It could be seen that mold mainly worked at the alcoholic stage.The molds mainly Generate reducing sugar at the AF.The number of yeasts grew rapidly to the largest 1.99×108 CFU/g after one day alcoholic fermentation.Until the 3th day of the AAF,the molds were all vanished.At 0 to 1 day of the AAF,alcohol precision also grew faster,yeast generated a large amount of ethanol.The number of lactic acid bacteria and the number of acetic acid bacteria decreased after the first increase in the alcoholic fermentation stage,the highest of number were 5.20×108 CFU/g and 5.36×107 CFU/g respectively,generating more lactic acid-based non-volatile acids.The number of lactic acid bacteria and the number of acetic acid bacteria of AAF also increase first and then reduced,the highest of number were 6.43×108 CFU/g and 7.23×106 CFU/g respectively,producing acetic acid mainly.The number of Bacillus spp.remained stable during AF and AAF,between 2.07×103?9.97×104 CFU/g.(3)The change regularity of physicolchemical indices in different fermentation periods.Reducing sugar content was 10.7g/100g at the end of glycosylation reaction.At 0 to 1 day of the AF,decreased significantly,the later maintained at 0 to 0.5 g/100g basically.At the AAF,reducing sugar contentrose increased firstly and then decreased,maintained between 0.70?2.70 g/100g.At 0 to 1 day of the AF,alcohol content increased significantly.At the 7th day,alcohol content of jiulao was the maximum of 9 0.At the AAF,alcohol content decreased gradually to the 8th day alcohol content reduced to 0.At the first day of the AF,pH value decreased significantly from 6.50 to 3.75,and then gradually stabilized(3.55?3.68).PH value decreased gradually at the AAF,and the minimum was 3.55.Especially,the total acid and non-volatile acids were rising at AF and AAF.At 0 to 3 day of the AF,total ester content increased significantly.The 4th day reached the maximum.At the AF and the AAF,the content of amino acid nitrogen showed a rising trend.(4)The variation regularity of volatile constituents in different fermentation periods.The results showed that the acid was decreased firstly and then increased at the AF.At the AAF,which showed a significant increase,and the peak area of 9th day was 2.86×1010 mv*min.The alcohol in the 9th day the peak area reached the maximum value of 2.01 ×1010 mv*min.At the AAF,the alcohol was a downward trend;esters showed a significant rise at the AF.At the AAF,the ester increased significantly during the alcoholic stage,and at the AAF which increased firstly,and then reached the maximum value of 4.18×1010 mv*min at 3rd day.The ester maintained stably.Acids,esters and alcohols were three volatile ingredients in the cupei and jiulao.And ketones,aldehydes,alkane and heterocyclic compounds content were relatively low in the cupei and jiulao.