Research On The Barley Vinegar Brewing Technology And Properties Comparison

Highland barley as the largest food crop in Tibet region of China is not only high in yield,but also rich in nutrition.Using highland barley as raw material to make vinegar can not only expand the raw material source of vinegar,but also solve the problem of local highland barley surplus.The study of optimization of liquefaction,saccharification,barley alcohol fermentation and acetic acid fermentation(by semi solid and liquid fermentation)process,and the analysis of changes of main components,aroma components and antioxidant ingredients,different fermentation modes in vinegar,in order to provide basis for the study on health function of barley vinegar.The results are as follows(1)Based on single factor test,orthogonal test and verification test of barley liquefaction,saccharification and alcohol fermentation,the optimum conditions for the liquefaction of barley: alpha amylase concentration 1%,hydrolysis time 12 h,PH was 6,the enzymolysis temperature is 60?,and reducing sugar content is 4.38g/100 m L in barley liquefaction.The optimum conditions for saccharification of barley: amylase concentration 0.3%,temperature 65?,hydrolysis time 4.0h,pH 4.5,the content of reducing sugar in barley saccharification liquidis 15.36g/100 mL.The optimum conditions of barley alcohol fermentation: the amount of yeast was 0.1%,initial PH 4.5,fermentation temperature is 30?,fermentation time 6d,barley alcohol content is 7.68g/100 mL.(2)On the basis of single factor experiment,the response surface test of semi solid condition of highland barley vinegar is carried out:Y=-58.98545+0.56460A+9.98897B+ 1.54728C-0.73702D+0.10050AB+0.23863AC-3.37885AD+0.20313BC-1.65385BD+5.19423CD-0.36035A2-1.15713B2-0.11088C2-218.75937D2.According to the influence of various factors on the fermentation vinegar,the optimal fermentation conditions are determined: acetic acid bacteria inoculation amount 10.64%,initial alcohol 7%(V/V),rice bran ratio 0.26,temperature 29.9 ?.Under these conditions,the content of acetic acid in highland barley vinegar is 5.50g/100 m L.(3)On the basis of single factor experiment,the response surface test of highland barley vinegar liquid fermentation is carried out: Y=-84.03292+11.57833A+2.51233B+ 3.40333C-0.086667D-0.0175AB-0.018750AC+0.11875AD-0.00425BC-0.00775BD-0.020625CD-1.00875A2-0.04375B2-0.12594C2-0.0034375D2.Accordingtothe influence of various factors on the fermentation vinegar,the optimal fermentation conditions of highland barley vinegar are determined as follows: initial alcohol 7.20%(V/V),liquid loading 24.30%,acetic acid bacteria inoculation amount 10%,temperature 32.50?.Under these conditions,the content of acetic acid in highland barley vinegar is 6.74g/100 m L.(4)The comparative study on antioxidation of semi solid fermentation barley vinegar and liquid fermention barley vinegar:The DPPH· clearance rate,ABTS+·clearance rate,·OH clearance rate and total reduction ability of semi-solid fermentation barley vinegar are significantly higher than those of liquid fermentation barley vinegar(P < 0.05);At the same time,the DPPH· clearance rate,the ABTS+· clearance rate and the ·OH clearance rate of the highland barley vinegar show an significantly increasing trend at normal temperature and low temperature aging(P < 0.05);the total reducing capacity of the highland barley vinegar show an extremely significant increasing trend(P < 0.01).The increase of aging at room temperature is higher than that in low temperature.(5)The comparative study on main components in semi solid fermentation of highland barley vinegar and liquid fermention barley vinegar:The content of residual sugar,reducing sugar,total flavonoids,VC content and total phenol in semi solid fermentation of highland barley vinegar is significantly higher than that of liquid fermentation of highland barley vinegar(P < 0.05).The content of acetic acid in semi solid fermentation of highland barley vinegar is significantly lower than that of liquid fermented highland barley vinegar(P < 0.05).The content of total polyphenol and total flavonoids show an significantly increasing trend(P < 0.05).The content of VC,reducing sugar and total acid show a significantly decreasing trend at normal temperature and low temperature aging(P < 0.05).The increase of aging at room temperature is higher than that in low temperature.(6)The comparative study on antioxidation and relative components of highland barley vinegar and vinegar:The results showed that the semi solid fermentation of highland barley vinegar is better than commercially available super vinegar,first grade vinegar,two grade vinegar in antioxidant activity(DPPH· clearance rate,ABTS+· clearance rate,·OH clearance rate,total reducing capacity),the content of VC,total phenolic and total flavonoid.(7)Comparison of aroma components in semi solid fermentation of highland barley vinegar and liquid fermention of highland barley vinegar:The aroma components of semi solid fermentation of highland barley vinegar and liquid fermentation of highland barley vinegar were detected: 50 and 32 aroma components,which accounte for 95.35% and 91.14% of the total aroma components,respectively.Ageing 6 months the aroma type of semi solid fermentation and liquid fermentation of highland barley barley vinegar vinegar is significantly increased.The aroma type of semi solid state fermentation of vinegar increase 34.The aroma type of liquid fermentation of barley vinegar increase 21.The content of esters and aldehyde-ketones are increaseing by 7.36%,17.85% and 18.72%,and 10.33%.The content of acids and alcohols are reduceing by 19.84%,9.03% and 5.32%,25.43%.The content of furan substance is increaseing by 1.16% in semi solid fermentation of highland barley vinegar.The contents of pyrazine and furan are increaseing by 1.67 %.Two kinds of fermentation methods of highland barley vinegar in the aging process,types of aroma substances are increasing.The aroma substance of semi solid fermentation of highland barley vinegar is more abundant than that of liquid fermentation highland barley vinegar.The flavor of semi solid fermentation of highland barley vinegar more rich than that of liquid fermentation highland barley vinegar.