The Study Of The Characteristic Flavor Compounds And Physical And Chemical Properties Of Different Rounds Maotai-flavor Base Baijiu

Baijiu is made from grains through cooking,saccharification,fermentation,and distillation,using daqu,xaoqu or bran koji and distiller’s yeast as eavening agents,which is one of the world’s six major distilled liquors.Maotai-flavour Baijiu is one of the four major flavor Baijiu.The process of traditional Maotaiflavour Baijiu is split into join the raw material twice,nine times fermentations,eight times distillations,and extractions baijiu seven times,the basic baijiu includes soy sauce aroma,sweet,base fragrance baijiu and different rounds baijiu,throughing storage,blending produce Maotai-flavour Baijiu.The quality of the round base Baijiu directly affects the quality of the finished Baijiu.Through the analysis of the physical and chemical properties,sensory characteristics,and key flavor compounds of the different round base Baijiu,it can guide the production of fermented grains,distillation and blending.This experiment discusses the physical and chemical quality changes of Maotai-flavor round base Baijiu,the composition and change of flavor compounds of Maotaiflavor round base Baijiu,the key flavor compounds of Maotai-flavor round base Baijiu and the correlation analysis with sensory characteristics,and the specific research content And the result is as follows:(1)Through the analysis of the physical and chemical properties of the different rounds Maotai-flavor round base Baijiu,it is found that the p H value of the base Baijiu in each round is between 3.607 ～ 3.767,the conductivity is between 53.2 ～75.9 us/cm,and the total acid content is between 1.69 ～4.595 g/L and the total ester content between 3.325 ～ 6.485 g/L in each round,it first decreased,then increased and then decreased;the total content of heavy metal elements was 18.557～91.078 ug/L,Among them,the elements with higher content are manganese and chromium,and the content in each round are8.295～32.561 ug/L,5.116～49.849 ug/L.(2)Two different pre-treatment methods combined with GC-Q/TOFMS methods for quantitative analysis of flavor compounds in Maotai-flavor Baijiu were investigated.Both methods can quantitatively analyze 60 flavor substances in Maotai-flavor Baijiu,including 12 alcohols,7 aldehydes,9 acids,22 esters,5pyrazinefurans,and 4 phenols.The direct injection method is superior to LLE(0.9866 ≥ R2 ≤ 0.9979,recovery rate is 76.25%～136.25%)in method linearity(0.99 ≥ R2 ≤ 0.9996)and recovery rate(84.36%～116.35%).And the direct injection method is simpler,the amount of experimental samples is less,and the operation process is safer.And through the verification of the direct sampling method,it is found that it can effectively detect the flavor of Maotaiflavor Baijiu.(3)Using direct sampling method combined with GC-Q/TOFMS,60 flavor compounds were quantified in Maotai-flavor rounds base Baijiu.In the base rounds Baijiu,the content of various flavor substances in order is esters(38.62%～55.21%),alcohols(15.79%～36.25%),acids(8.06%～23.36%),aldehydes(5.46%～21.14)%),and compared the changes of 24 flavor skeleton substances in different rounds Maotai-flavor base Baijiu.(4)Through PCA and HCA,it is possible to better cluster and distinguish different rounds of Maotai-flavor base Baijiu.PCA found that the first round of base Baijiu had a greater impact on n-propanol,ethyl stearate,ethyl palmitate,Acetic acid,propionic acid,ethyl acetate and other compounds.The compounds that have a greater impact on the second round of base Baijiu are npropanol,ethyl acetate,ethyl butyrate,propionic acid,acetic acid and other compounds.Ethyl pentadecanoate,ethyl palmitate,and ethyl oleate are the major contribution to the third round base Baijiu.The major contribution to the fourth round of base wine is ethyl lactate.sobutyraldehyde,ethyl 2-furoate,and diethyl succinate have a greater impact on the fifth round base Baijiu.The major contributions to the sixth round of secondary base Baijiu are ethyl caproate,2,3-butanediol,caproic acid,palmitoleic acid and other compounds.The seventh round base Baijiu is greatly affected by compounds such as acetaldehyde,ethyl valerate,ethyl heptanoate,n-pentanol,acetal,and 2,5-dimethylpyrazine.(5)The sensory evaluation results of the Maotai-flavored base Baijiu found that the first and second rounds had more outstanding grain aroma.In the third round,except the aroma of cellar,the other aroma scores are balanced,the sauce is slightly stronger.The fourth round base Baijiu sauce is outstanding.For the fifth round base Baijiu,caramel,daqu aroma and baking aromas are more obvious.In the sixth round base Baijiu,the scorched aroma and caramel aroma were outstanding.In the seventh round,the wine was fragrant with sauce,burntflavored,mellow,and smell of distiller’s grains.Through PLSR,it was found that compounds such as ethyl caprylate,hexanol,isoamyl alcohol,isobutanol,etc,contributed to the fragrance of daqu aroma.Grain aroma is mainly affected by sec-butanol.The floral and fruity aroma and mellow aroma are greatly affected by isobutanol.The major contributions to sauce are butanediol,ethyl caprylate ethyl 2-furoate,isovaleric acid,2,3-butanediol and other compounds.Compounds such as isovaleric acid,furfuryl alcohol,acetal,ethyl valerate,and furfural have a common effect on caramel and burnt odor.Benzyl alcohol and ethyl succinate have caused the difference between caramel and burnt scents.Benzyl alcohol and ethyl succinate have caused the difference between caramel and burnt scents.The smell of distiller’s grains is also affected by 2-methylbutanol and propionic acid.