Research On The Compositions And Influencing Factors Of Main Organic Acids In Wheat Beer

Wheat beer is populared by the public because of its unique aroma and rich nutrients,however,The taste of wheat beer is slightly sour or sour in storage period,which will reduce the taste of wheat beer.The change of acid is mainly formed by organic acid.This study mainly studies the composition and influencing factors of the main organic acids of wheat beer acidity.Firstly,a method for the determination of organic acids in wheat beer was established.The separation effect,linear correlation and recovery rate of organic acids were obtained by HPLC,and the determination method of organic acids in wheat beer was determined by comparing with the conventional method:SPE solid phase extraction column pretreatment,Tiank C₁₈column separation,mobile phase in 0.02 mo L·L^-1 H₃PO₄(pH=2.7),flow rate is 0.425 mL·min^-1,UV detection wavelength is 210 nm.The recovery rate of this method is 83%,RSD<0.04%,and the linear correlation coefficient R² of organic acid is more than 0.9994,which can realize the separation and accurate quantification of 7 organic acids.Secondly,taking the conventional index and sensory evaluation of wheat beer as the evaluation standard,through the determination of 20 kinds of common indexes such as organic acid,total acid and Alcohol content of wheat beer sold at home and abroad and the sensory evaluation results of 50 reviewers,the wheat beer No.11 and No.2 with the best flavor and soft acid taste were selected,and the organic acid was analyzed.Through the composition and content analysis of organic acids,the main organic acids of wheat beer acidity were determined to be succinic acid and citric acid,with the content range of 2.85-28.71 ug·mL^-1 and 8.57-12.85ug·mL^-1 respectively.Among them,the best range of organic acid flavor and acidity of wheat beer is:malic acid content range is 0.24-0.66 ug·mL^-1,oxalic acid content range is 0.50-0.65ug·mL^-1,succinic acid content range is 2.85-13.19 ug·mL^-1,tartaric acid content range is10.25-10.84 ug·mL^-1,lactic acid content range is 0-7.00 ug·mL^-1,acetic acid content range is0.07-1.96 ug·mL^-1,citric acid content range is 8.13-13.47 ug·mL^-1.In this range,the acid sensitivity of wheat beer was negatively correlated with the content of succinic acid,and negatively correlated with the total content of seven main organic acids.Finally,according to the content,composition and evaluation methods of organic acids in wheat beer,the production range of organic acids in wheat beer was regulated by yeast screening and fermentation technology.20 kinds of wheat beer yeast were selected to ferment under the same conditions,and yeast No.3 was optimized.The fermentation technology of yeast No.3 was studied as follows:the ratio of small malt and large malt was 4:6;when the wort concentration was 12°P,the fermentation temperature was 20?,and the fermentation tank pressure was 0.02 MPa,the content of 7 kinds of organic acids was higher than that of 4 kinds of organic acids in the content range of better flavor and acid sense of wheat beer,and 7kinds of organic acids The content of total acid is the lowest,and the content of total acid is in the best range of flavor acidity.